Beaumont Site Visit: Management of Stalk Borers Attacking Sugarcane, Energycane, Sorghum, and Rice

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1 Beaumont Site Visit: Management of Stalk Borers Attacking Sugarcane, Energycane, Sorghum, and Rice Project Investigators: Graduate Assistants: Gene Reagan, LSU AgCenter, Department of Entomology M.O. Way, Texas A&M AgriLife Beaumont Julien Beuzelin, LSU AgCenter, Dean Lee Research Station Matt VanWeelden Blake Wilson Cooperators: Bill White, USDA ARS Sugarcane Research Scientist Tony Prado, Rio Grande Valley Sugar Growers Inc. Allan Showler, USDA ARS, Kerrville, TX and Rebecca Pearson, Texas AgriLife Beaumont Suhas Vyavhare, Texas AgriLife Beaumont Randy Richard, USDA ARS Sugarcane Research Station 18 September, 2013 This work has been supported by grants from the USDA CSREES Southern Region IPM and Crops at Risk programs, USDA NIFA AFRI Sustainable Bioenergy program, and U.S. EPA Strategic Agricultural Initiative and Agricultural IPM programs. We also thank the Texas Rice Research Foundation, the American Sugar Cane League, Rio Grande Valley Sugar Growers Inc, participating Agricultural Chemical Companies, the Texas Department of Agriculture, and the Louisiana Department of Agriculture and Forestry for their support.

2 COMPARISON OF STALK BORERS ATTACKING SUGARCANE AND RICE (a) Adult female sugarcane borer (b) Sugarcane borer larva (c) Adult female Mexican rice borer (d) Mexican rice borer larva (e) Adult female rice stalk borer (f) Rice stalk borer larva Photos: (a) B. Castro; (b) J. Saichuk; (c) F. Reay-Jones; (d)(e)(f) A. Meszaros

3 Table of Contents Comparison of Stemborers Attacking Graminaceous Crops..1 Field Research Site Visit Announcement...4 Site Visit Agenda....5 Mexican Rice Borer Establishment in Louisiana....6 Sugarcane Research Aerial Insecticidal Control of the Mexican Rice Borer in Sugarcane, Rio Grande Valley, TX Small Plot Evaluation of Insecticidal Control of the Sugarcane Borer in Louisiana Sugarcane, Evaluation of Commercial and Experimental Sugarcane Cultivars for Resistance to the Mexican Rice Borer, Beaumont, TX, 2011 and Bioenergy Crops Research Estimating Yield Loss by the Mexican Rice Borer in Sugarcane, Energycane, and High-Biomass Sorghum Effect of Fertilization Regime on Infestation by the Mexican Rice Borer in Bioenergy Sorghum Sugarcane Borer Injury to Sugarcane, Energycane, and Sorghum Cultivars with Bioenergy Potential in Louisiana Effectiveness of the Red Imported Fire Ant in Reducing Mexican Rice Borer Injury in Conventional and Bioenergy Cropping Systems..19 Rice Research Management of Stalk Borers in Texas Rice. 20 Evaluation of Insecticidal Seed Treatments for Control of Rice Water Weevil and Stalk Borers in Early Planted Rice, Beaumont, TX, Evaluation of Insecticidal Seed Treatments and Foliar Applications for Control of Rice Water Weevil and Stalk Borers in Water Seeded Rice, Beaumont, TX, The Effect of Intertrap Distance on the Performance of Mexican Rice Borer Pheromone Traps in Stubble Rice...29

4 Peer Reviewed Publications Improved Chemical Control of the Mexican Rice Borer (Lepidoptera: Crambidae) In Sugarcane: Larval Exposure, a Novel Scouting Method and Efficacy of a Single Aerial Insecticide Application Oviposition and Larval Development of a Stem Borer, Eoreuma loftini, on Rice and Non-crop Grass Hosts.40 Appendices Appendix A: Insect Nursery Site Map 55 Appendix B: Bioenergy Test Plot Map.. 56 Appendix C: Sorghum Fertilization Test Plot Plan. 57 Appendix D: Host Plant Resistance Tests 2011 and 2012 Plot Plans Appendix E: Energycane/Miscane Map

5 Texas A&M AgriLife Research and Extension Center at Beaumont LSU AgCenter USDA, Houma, LA Gene Reagan, Matt VanWeelden, Blake Wilson, Julien Beuzelin, Jeff Hoy, Bill White, Ted Wilson, Yubin Yang, Mo Way and Becky Pearson The Beaumont Center will host a Site Visit on September 18, 2013 to discuss recent research results regarding stalk borers (particularly Mexican rice borer) attacking energycane, sweet sorghum and rice. The goal of this visit is to educate stakeholders about progress towards managing stalk borers---particularly Mexican rice borer. Attendees will meet in the auditorium before going to the field to observe stalk borer experiments in progress on energycane, sweet sorghum and rice. This will be an informal visit with plenty of time for questions and discussion. Following the field visit, attendees will again meet in the auditorium for sandwiches, snacks and drinks while continuing to exchange information. CEUs will be provided. Below is a summary of the details of the site visit: Where: Beaumont Center, 1509 Aggie Dr., Beaumont, TX When: Wednesday September 18, 2013 Time: Starts at 10am and ends about 1pm (starting later than in the past to allow attendees to avoid overnight stay) Contact: Mo Way, moway@aesrg.tamu.edu, for more information, if needed. Please RSVP Mo by if you plan to attend---this will help determine sandwich, snack and drink orders. Hope to see you September 18---drive safely!

6 AGENDA FOR BEAUMONT CENTER SITE VISIT Management of Stalk Borers Attacking Energycane, Sweet Sorghum and Rice September 18, 2013 from 10:00 to 1:00 10:00-10:15 Sign-in and introduction, Beaumont Center auditorium: Dr. Mo Way 10:15-10:25 Drive to site of energycane/sweet sorghum plots 10:25-11:30 LSU AgCenter staff (Drs. Gene Reagan, Jeff Hoy and Julien Beuzelin, and Graduate Students Matt VanWeelden and Blake Wilson) and USDA/Houma, LA (Dr. Bill White) will discuss distribution, identification, life history, damage and management of Mexican rice borer relative to current experiments; hands-on inspection of plots 11:30-11:40 Drive to energycane/miscane plots 11:40-12:00 Dr. Yubin Yang, Texas A&M AgriLife Research, will discuss current agronomic research on energycane and miscane 12:00-12:05 Drive to rice plots 12:05-12:25 Dr. Mo Way, Texas A&M AgriLife Research, will discuss current research on management of stalk borers in rice; hands-on inspection of plots 12:25-12:30 Drive back to auditorium 12:30-1:00 Light lunch and further discussion of stalk borer Integrated Pest Management (IPM) research and application 1:00 Adjourn

7 MEXICAN RICE BORER ESTABLISHMENT IN LOUISIANA B.E. Wilson 1, M.T. VanWeelden 1, J.M. Beuzelin 1, T.E. Reagan 1, J. Meaux 2, T. Hardy 3, and R. Miller 3 1 LSU AgCenter, Department of Entomology 2 LSU AgCenter, Calcasieu Parish Extension Office 3 Louisiana Department of Agriculture and Forestry Cooperative studies on the Mexican rice borer (MRB), Eoreuma loftini, between the LSU AgCenter, Texas A&M University AgriLIFE research station at Beaumont, the Texas Department of Agriculture, and the Louisiana Department of Agriculture and Forestry have been on-going since 1999 to monitor the movement of this devastating pest of sugarcane into Louisiana. As previously anticipated, MRB spread into Louisiana by the end of 2008, and was collected in two traps near rice fields northwest of Vinton, LA on December 15. Since then, extensive trapping of MRB has been conducted in southwest Louisiana by LDAF and LSU AgCenter personnel. Currently, more than 100 traps are being monitored in ten Parishes in Louisiana. To date, pheromone traps have detected MRB moths in Calcasieu, Cameron, Jefferson Davis, Beauregard, and Allen Parishes. The range extends from the Gulf Coast north to Oberlin, LA and east to Jennings, LA (Fig. 1). The MRB is now present throughout Cameron and Calcasieu Parishes and pheromone trap captures indicate substantial populations are present in these areas (Table 1). Additional surveys are being conducted to monitor MRB infestations in rice, sugarcane, corn and other host crops. A MRB larval infestation was detected for the first time in a Louisiana sugarcane field on March 29, The pest was found south of I-10 approximately 2.5 miles west of Iowa, LA in Calcasieu Parish in a field of variety L plant cane. While this finding was expected as the invasive pest has been slowly approaching commercial sugarcane production areas in Louisiana from the west for years, the detection serves as a reminder that sugar producers across the state will soon have a new pest to consider. Larval infestations in rice in Calcasieu Parish are reaching economically damaging levels. White heads attributable to MRB infestations were recorded in 4% of rice shoots in fields which did not receive insecticide seed treatments in While the pest has been moving eastward at roughly 10 miles/year in Louisiana, recent detection of MRB in Florida demonstrates the species potential for rapid expansion and highlights the need for statewide monitoring. Due to its utilization of alternative host crops and weedy grass hosts, control measures are not expected to be effective in stopping the eastward spread into larger sugarcane production regions in Louisiana. Eradication of MRB is not a viable option because of the pest s use of non-crop hosts. Pest management decisions regarding actions to control MRB infestations should be considered on a field-by-field basis and based on recommended thresholds. In addition, processing sugarcane infested with MRB at the closest mill will reduce the risk of man-assisted movement farther into the heart of the Louisiana sugarcane production area. LSU AgCenter entomologists are continuing to research new management strategies and provide up-to-date information regarding the risk of MRB in your area. The AgCenter has partnered with Pennsylvania State University to develop PestWatch, a real-time web mapping system which will provide online access to the most current MRB

8 distribution data. The PestWatch mapping system for MRB is scheduled to be launched by June 2013 and will be openly accessible to the public. Further information on MRB biology and management, as well as pictures to aide in identification, can be found on the LSU AgCenter Website ( Mexican-Rice-Borer.htm). If you suspect you may have an infestation of MRB or would like to monitor a pheromone trap in your area contact LSU AgCenter Entomologists, Blake Wilson, at bwilson@agcenter.lsu.edu, or Julien Beuzelin, at jbeuzelin@agcenter.lsu.edu. Table 1: Mexican rice borer pheromone trap captures in southwest Louisiana Parishes, Data represent means of multiple traps in each parish. Parish MRB/Trap/Day March April May June July Aug Calcasieu Cameron Jeff. Davis Allen Beauregard

9 Figure 1: Mexican rice borer distribution in SW Louisiana as of August Red pins indicate MRB positive traps, Yellow pins indicate traps sites which have not yet detected MRB. Additional traps present in Vermillion, Rapides, Evangeline, St. Martin, and St. Landry Parishes are not shown and have not detected MRB.

10 AERIAL INSECTICIDAL CONTROL OF MEXICAN RICE BORER IN SUGARCANE RIO GRANDE VALLEY, TX, 2012 M.T. VanWeelden, B.E. Wilson, T.E. Reagan, and J.M. Beuzelin LSU AgCenter, Department of Entomology Evaluation of aerial application control of the Mexican rice borer (MRB), Eoreuma loftini, in sugarcane was conducted in the Rio Grande Valley (Cameron and Hidalgo Counties) of Texas in Insecticide treatments were randomly assigned to plots (8-10 acres/plot) in commercial sugarcane fields of variety CP Pheromone traps were used to monitor MRB populations throughout the growing season. Larval scouting was conducted by examining 100 stalks in each field on 21 Aug 2012 and revealed that infestations exceeded the threshold of 5% of stalks with treatable larvae on plant surfaces. The aerial application was made the morning of 22 Aug by fixed wing aircraft flying at 145 mph. All treatments were applied with 10 gallons of water per acre. MRB injury data were collected on 29 Oct 2012 from 15-stalk samples taken from 2 locations in each test plot. Differences between treatments were detected for both percent bored internodes and adult emergence per stalk (Table 1). Mean percent bored internodes ranged from 3.36% (Belt ) to 12.64% (untreated), and mean emergence ranged from 0.13 (Prevathon ) to 0.46 (untreated) emergence holes/stalk. Percent bored internodes in Belt and Prevathon treated plots was significantly lower than in untreated controls. However, only Prevathon treatments significantly reduced adult emergence per stalk. Yield data were collected by the core sampling method and all plots were harvested completely. Two replications were harvested on 19 Dec 2013, one 8 Feb 2013, and two on March, None of the treatments had significantly higher yield than untreated controls (Table 1). Yield was highest in Belt treated plots and lowest in Confirm treated plots. Further MRB injury received in treated plots after bored internode data was collected in October is a potential explanation for the lack of differences in yield despite having reduced injury in treated plots. The MRB remains active throughout the winter in the Rio Grande Valley. Data indicate that new diamide chemistries, Belt and Prevathon, may provide better control of the MRB than either Confirm or Diamond. Table 1. Mexican rice borer injury and sugarcane yield. Aerial application trial, Cameron and Hidalgo Counties, TX Trade Common Rate (fl Emergence Tons of Tons of % Bored Name Name oz/acre) /stalk Cane/Acre Sugar/Acre Untreated NA NA 12.64a 0.46a 40.36ab 4.64a Confirm Tebufenozide ab 0.32ab 33.57b 3.77b Diamond Novaluron ab 0.21ab 39.07ab 4.54ab Prevathon Rynaxypyr b 0.13b 41.43a 4.54ab Belt Flubendiamide b 0.22ab 43.26a 4.80a df = 4, , , , F = P= *Means which share a letter are not significantly different (Tukey s HSD, α = 0.05)

11 SMALL PLOT EVALUATION OF INSECTICIDAL CONTROL OF THE SUGARCANE BORER IN LOUISIANA SUGARCANE, 2011 B.E. Wilson, J.M. Beuzelin, M.T. VanWeelden, and T.E. Reagan LSU AgCenter, Department of Entomology Seven insecticide treatments in addition to an untreated control were evaluated for season long control of the SCB in a randomized block design with five replications in a sugarcane field of 2 nd ratoon HoCP in Burns Point, LA (St. Mary Parish). Treatment plots consisted of three 24-ft rows (0.01 acre) separated by 5-ft gaps. Two insecticide applications were made the mornings of 5 Aug and 30 Aug when infestations exceeded the treatment threshold of 5% of stalks with borer larvae present in leaf sheaths. Insecticides were mixed in 2 gal of water and applied using a Solo back pack sprayer delivering 40 gallons/acre at 20 psi. Borer injury to sugarcane was assessed at the time of harvest (5 Oct) by counting the total number of internodes (15 stalks/plot), number of bored internodes and moth emergence holes in each stalk. Proportion of bored internodes was analyzed using a generalized linear mixed model (Proc Glimmix, SAS Institute) with a binomial distribution, and means were separated with Tukey s HSD (α = 0.05). Emergence data was analyzed using a generalized linear mixed model (Proc Glimmix, SAS Institute) with a normal distribution. Insecticide treatments provided substantial control and significantly reduced the proportion of bored internodes when compared to untreated checks (F = 70.8, P <0.0001, df = 7, 587). Percentage of bored internodes in the treated plots ranged between % compared to the 20.3% observed in the untreated check. Besiege applied at 9.0 oz/acre showed greatest reduction in internode injury; however, differences were not detected among the insecticide treatments. Adult emergence ranged between emergence holes per stalk, and followed the same trend as percentage bored internodes (F = 26.7, P <0.0001, df = 7, 586). All insecticide treatments were significantly better than the untreated check. Table 1: SCB injury after two insecticide applications, St. Mary Parish, LA, Treatment a Rate (fl oz/acre) % Bored Internodes Emergence/Stalk Control NA 20.3 B 0.72 B Prevathon (low) A 0.03 A Prevathon (high) A 0.04 A Belt A 0.01 A Coragen A 0.01 A Confirm A 0.03 A Diamond A 0.00 A Besiege A 0.00 A a Insecticide treatments were applied with Induce surfactant at 0.5% v/v. Means within column followed by the same letter are not significantly different (P = 0.05, Tukey s HSD).

12 EVALUATION OF COMMERCIAL AND EXPERIMENTAL SUGARCANE CULTIVARS FOR RESISTANCE TO THE MEXICAN RICE BORER, BEAUMONT, TX, 2011 AND 2012 T.E. Reagan 1, B.E. Wilson 1, M.T. VanWeelden 1, and J.M. Beuzelin, W.H. White 2, R. Richard 2, and M.O. Way 3 11 LSU AgCenter, Department of Entomology 2 USDA-ARS, Sugarcane Research Unit at Houma, Louisiana 3 Texas A&M AgriLIFE Research and Extension Center at Beaumont, Texas Because of the limitations of chemical and biological control against the Mexican rice borer (MRB), Eoreuma loftini, host plant resistance is an important part of IPM. As a control tactic, host plant resistance can not only aid in reducing stalkborer injury, but can also reduce area-wide populations and potentially slow the spread of the MRB. The effect of cultivars on reducing area-wide populations is examined by comparing the number of adult emergence holes. In addition, recent research suggests resistant cultivars which impede stalk entry and prolong larval exposure on plant surfaces may enhance the efficacy insecticide applications (See pages 31-40). Continued evaluation of stalkborer resistance is necessary as host plant resistance remains a valuable tool in stalkborer IPM. A 2-year field studies were conducted at the Texas A&M AgriLIFE Research and Extension Center at Beaumont, TX, to assess cultivar resistance to the MRB among commercial and experimental sugarcane cultivars in 2011 and Over both years, 33 cultivars were evaluated. The tests included a wide variety of cultivars developed from breeding programs in St. Gabriel, LA; Houma, LA; and Canal Point, FL. In addition, the 2012 test examined resistance in 4 biomass energy cultivars. In both years, the tests had 1-row, 12-foot plots arranged in a randomized block design with 5 replications (See Appendix D) The 2011 test evaluated resistance in 19 cultivars. HoCP has been a resistant standard for many years. HoCP , which appears to have little resistance to the MRB, has recently been released to commercial growers. Experimental cultivars in the early stages of varietal development which were evaluated include: HoCP , Ho , L , L , Ho , Ho , HoL , L , L , Ho Two energy cane varieties, L and Ho , were also evaluated. Results showed significant differences (F=2.71, P= ) in injury which ranged from % bored internodes (Table 1). The most resistant cultivars examined were HoCP and L Experimental cultivar, L , is potentially highly resistant as it demonstrated >8-fold reductions in MRB injury compared to susceptible cultivars. The most susceptible cultivars were HoCP , L , and HoCP Differences in adult emergence (F= 1.99, P =0.0187) followed the same trend as injury data ranging from emergence hole per stalk (Table 2). Energy cane varieties showed intermediate levels of resistance.

13 Table 1: Borer Injury and Moth Production, Beaumont Variety Test 2011 Variety % Bored Emergence/stalk HoCP L HoCP HoL Ho Ho Ho Ho L L Ho L HoCP Ho L Ho HoCP HoCP L *Means which share a line are not significantly different (LSD α=0.05) Resistance to the MRB was evaluated in cultivars of sugarcane, energycane, and sorghum. Commercial sugarcane varieties included were HoCP (resistant), HoCP (susceptible), and Ho (intermediate). Seven experimental cultivars from the sugarcane variety development programs at LSU and USDA-Houma included were L , L , L , Ho , Ho , Ho , and Ho Five sugarcane cultivars commonly grown in the Rio Grande Valley of Texas (CP , CP , TCP , TCP , TCP ) were also evaluated. Cultivars with potential for bioenergy production include six energycanes (L , Ho , Ho , Ho , Ho , and Ho ), two energy sorghums (ES 5200 and ES 5140), and one sweet sorghum (M81E). Sugarcane and energycane cultivars were planted 26 October 2011; sorghum was planted 19 April On 22 October 2012, twelve randomly selected stalks were collected from each plot and the total no. internodes, the no. bored internodes, and the no. emergence holes were recorded. The sugarcane borer, Diatraea saccharalis, is present in the Beaumont area, however, the stem borer population was >90% MRB in The percentage of bored internodes and no. emergence holes per stalk were analyzed using generalized linear mixed models (Proc Glimmix,

14 SAS Institute) with binomial and Gaussian distributions, respectively. Results show significant differences between cultivars (df = 23, 96; F = 14.46; P <0.0001) in percentage of bored internodes which ranged from 6.01 to 26.47% (Table 2). Differences were also detected in the no. emergence holes pre stalk (df = 23, 96; F = 3.05; P <0.0001) which ranged from 0.11 to 1.43 (Table 3). Consistent with results from previous evaluations, HoCP was the least injured (% bored) of all cultivars tested. Experimental cultivar, L , was the most susceptible in terms of both injury and adult emergence. All of the energycane cultivars demonstrated moderate to high levels of resistance. The three sorghum varieties demonstrated a high degree of susceptibility. Table 2. Mexican Rice Borer Injury Cultivar Crop % Bored Internodes L SC CP SC M81E SS CP SC Ho SC HoCP SC ES 5140 ES Ho SC L SC ES 5200 ES TCP SC L SC Ho SC Ho SC Ho SC Ho EC TCP SC L EC Ho EC TCP SC Ho EC Ho EC 9.55 Ho EC 9.03 Table 3. Mexican Rice Borer Moth Production Cultivar Crop L SC 1.43 L SC 1.01 CP SC 0.98 ES 5200 ES 0.98 HoCP SC 0.95 CP SC 0.87 M81E SS 0.82 ES 5140 ES 0.77 Ho SC 0.72 Ho SC 0.70 TCP SC 0.67 Ho SC 0.63 Ho SC 0.55 Ho SC 0.55 L SC 0.47 TCP SC 0.46 Ho EC 0.32 TCP SC 0.28 Ho EC 0.28 HoCP SC 0.23 Ho EC 0.23 L EC 0.20 Ho EC 0.14 Ho EC 0.11 HoCP SC 6.01 *SC = Sugarcane, EC = Energycane, ES = Energy Sorghum, SS = Sweet Sorghum **Means which share a line are not significantly different (Tukey s HSD, α = 0.05) Emergence Holes/Stalk

15 ESTIMATING YIELD LOSS BY THE MEXICAN RICE BORER IN SUGARCANE, ENERGYCANE AND HIGH-BIOMASS SORGHUM M.T. VanWeelden 1, B.E. Wilson 1, J.M. Beuzelin 1, T.E. Reagan 1, and M.O. Way 2 1 LSU AgCenter, Department of Entomology 2 Texas A&M AgriLIFE Research and Extension Center, Beaumont, TX The Mexican rice borer (MRB), Eoreuma loftini, is an invasive stem-borer, which poses a threat to crops grown for biofuel production in the Gulf Coast Region. An experiment was conducted in 2012 at the Texas A&M AgriLIFE Research and Extension Center in Beaumont to evaluate yield loss by the MRB among varieties of sugarcane, energycane, and energy sorghum. Two sugarcane varieties (HoCP and HoCP ) and two energycane varieties (L and Ho ) were evaluated. Two high-biomass sorghum varieties (ES 5200 and ES 5140) and one sweet sorghum variety (M81E), which have potential for biofuel production, were also evaluated. The experiment was arranged using a split-plot design with four replications (Appendix B). Replications consisted of seven, 3-row plots (72 ft long, 5.25 ft row spacing). Crop varieties were randomized to plot. Plots were further divided into four, 3- row subplots (18 ft long) and subjected to one of four MRB infestation levels: protected (biweekly application of tebufenozide), natural infestation, enhanced infestation, and highlyenhanced infestation. To achieve enhanced infestation levels, MRB egg masses (~30 eggs) were clipped to the basal leaves of each plant. Three 4-stalk samples were collected from each subplot at the end of the season and the no. bored internodes and emergence holes were recorded. Stalks were weighed and crushed to calculate total sugar, dry weight, and theoretical ethanol output. Theoretical ethanol output was calculated using methods described by Vasilakoglou et al. (2011, Field Crops Res. 120: 38-46). Differences were detected in the percentage of bored internodes across variety, infestation level, and variety by infestation level (Table 1). Tebufenozide was successful in suppressing injury to < 1.0% bored internodes in all subplots subjected to protected infestation levels. In subplots with highly-enhanced infestations, the percentage of bored internodes ranged from %, with varieties of energycane (L and Ho ) and sweet sorghum (M81E) expressing higher levels of resistance. In terms of yield, differences in wet weight per stalk were detected across varieties and infestation levels. Higher infestations were associated with a decrease in wet weight for all varieties. A negative impact in yield was also evident in terms of theoretical ethanol production, as decreases in ethanol productivity were observed with enhanced infestations. In highly-enhanced infestations, decreases in ethanol production ranged from 12 42% when compared to suppressed subplots. For both conventional and bioenergy varieties, maximum ethanol productivity was achieved in MRB-protected subplots. Results from this study demonstrate that the MRB has potential to reduce yield in bioenergy crops. Current IPM practices will need to be implemented into bioenergy cropping systems in order to reduce yield-losses under high borer pressure.

16 Table 1: Mexican rice borer injury and yield parameters for sugarcane, energycane, highbiomass sorghum, and sweet sorghum varieties with varying infestation levels (1=control, 2=natural, 3=enhanced, 4=highly-enhanced). Replicated field trial, Beaumont, TX, Variety Energycane L Energycane Ho Sugarcane HoCP Sugarcane HoCP High-biomass Sorghum ES 5200 High-biomass Sorghum ES 5140 Sweet Sorghum M81E Type III Test of Fixed Effects Infestation Level Variety Infestation Level Variety* Infestation Level Percent Bored Internodes F = 3.29 P = F = P < F = 2.71 P = Weight (kg)/stalk F = P < F = P < F = 1.41 P = Theoretical Ethanol Output (L/ha) F = P < F = P < F = 1.49 P = This research work is a portion of the Ph.D. program of study by Matthew VanWeelden in the LSU Department of Entomology.

17 SUGARCANE BORER INJURY TO SUGARCANE, ENERGYCANE, AND SORGHUM CULTIVARS WITH BIOENERGY POTENTIAL IN LOUISIANA B.E. Wilson, M.T. VanWeelden, T.E. Reagan, and J.M. Beuzelin LSU AgCenter, Department of Entomology The U.S. Gulf Coast is among the geographic regions with the highest potential for production of dedicated cellulosic bioenergy crops, especially energycane and high-biomass sorghum. The most destructive pest of sugarcane in Louisiana is the sugarcane borer (SCB), Diatraea saccharalis, which also attack graminaceous bioenergy crops. However, the potential of this pest to cause yield losses in bioenergy crops remains unknown. This study examines the effect of SCB injury under natural pest pressure and associated yield loss in sugarcane, energycane, high-biomass sorghum, and sweet sorghum in two locations in Louisiana. Cultivars which were evaluated include SCB resistant sugarcane (HoCP ), susceptible sugarcane (HoCP ), two energycanes (L and Ho ), sweet sorghum (M81E), and two high-biomass sorghums (ES 5200 and ES 5140). Cultivars were evaluated in replicated field studies in Rapides Parish (2011 and 2012) and St. Mary Parish (2012). Plots of each variety were divided into protected (biweekly applications of tebufenozide) and unprotected (no insecticides) subplots. The crop production area around the Rapides Parish field site (near Cheneyville, LA) consists of a diverse mosaic of multiple row crops including corn, grain sorghum, sugarcane, rice, soybeans, and cotton. The area surrounding the St. Mary Parish location (near Burns Point, LA) is entirely devoted to sugarcane production. Natural populations of SCB in Rapides Parish in 2011 were very low and percentage of bored internodes averaged < 1.0% in all cultivars. SCB infestations in unprotected plots in Rapides Parish in 2012 ( % bored internodes) were slightly higher than in 2011, and significant differences were detected among cultivars (Table 1). Mean borer injury was greater than 5-fold higher at the St. Mary Parish location than in Rapides Parish in SCB injury to unprotected plots in St. Mary Parish in 2012 (Table 2) ranged from 3.4% (HoCP ) to 17.7% bored internodes (HoCP ). Differences were detected (P < 0.001) in both percentage of bored internodes and number of adult emergence holes among cultivars. Tebufenozide applications were effective in reducing SBC injury to <1% bored for all cultivars evaluated, and protected plots were used to calculate yield loss attributable to SCB injury. Yield loss was based on the difference in mean stalk weight between protected and unprotected plots of each cultivar. Yield loss (Table 2) was greatest in sweet sorghum M81E (26.1%) and least in energycane Ho (5.9%). High-biomass sorghums suffered yield losses of 22 24%. Energycane Ho is relatively resistant to SCB. Results from these studies demonstrate that natural levels of SCB infestations have potential to cause substantial yield loss in bioenergy crops. Host plant resistance will continue to be important to SCB management in bioenergy and conventional crops. Levels of resistance are crop- and cultivar-specific. Insecticidal protection including development of cultivar-specific thresholds will be required to achieve maximum yields. Additionally, a landscape approach must be used to assess the interactive role of pest management in conventional and bioenergy crops.

18 Table 1: SCB injury to unprotected plots, Rapides Parish, LA, % Bored internodes No. emergence holes/stalk High-biomass Sorghum ES b 0.08 ES b 0.07 Sweet Sorghum M81E 7.1 a 0.33 Energycane Sugarcane L ab 0.14 Ho b 0.05 HoCP ab 0.12 HoCP b 0.02 F-value; P > F F = 3.2; P = F = 2.4; P = *Means followed by the same a letter are not different (Tukey s HSD, α = 0.05) Table 2: SCB injury to unprotected plots and associated yield loss, St. Mary Parish, LA, % Bored internodes No. emergence holes/stalk % Yield Loss High-biomass Sorghum ES abc 0.34 b 22.4 ab ES a 0.90 b 24.3 a Sweet Sorghum M81E 14.6 ab 0.75 b 26.1 a Energycane Sugarcane L abc 0.79 b 10.5 bc Ho bc 0.39 b 5.8 c HoCP a 1.90 a 18.8 abc HoCP c 0.22 b 9.0 b F-value P > F F = 6.0 P < F = 9.1 P < *Means followed by the same a letter are not different (Tukey s HSD, α = 0.05) F = 7.6 P < 0.001

19 EFFECT OF FERTILIZATION REGIME ON INFESTATION BY THE MEXICAN RICE BORER IN BIOENERGY SORGHUM M.T. VanWeelden 1, B.E. Wilson 1, J.M Beuzelin 1, T.E. Reagan 1, and M.O. Way 2 1 LSU AgCenter, Department of Entomology 2 Texas A&M AgriLIFE Research and Extension Center, Beaumont, TX A study was initiated in 2013 at the Texas A&M AgriLIFE Research and Extension Center in Beaumont, Texas to assess the impact of nitrogen fertility on infestation by the Mexican rice borer (MRB), Eoreuma loftini, in varieties of sorghum used in production of biofuels. Two varieties of high-biomass sorghum (ES 5200 and ES 5140) and one variety of sweet sorghum (M81E) were evaluated in this experiment. The experiment was arranged using split-plot design with four replications. Replications consisted of four, 6-row plots (75 ft long, 3 ft row spacing). Four nitrogen rates (0, 40, 80, or 120 lbs N/acre) were randomized to plots. Plots were further divided into three, 2-row subplots, which were assigned to sorghum varieties. Prior to planting, soil samples were collected in fifteen random locations across the field and sent to the LSU AgCenter Soil Testing and Plant Analysis Lab to determine preexisting nitrogen levels. Urea was applied to the soil by hand immediately after planting. Plants are currently being checked on a regular schedule for MRB-related injury. In addition, minor pests such as aphids and armyworms will be monitored throughout the growing season. Since early June, populations of the sugarcane aphid, Melanaphis sacchari, have been high throughout the entire test, though most damage remains exclusively on M81E and ES An application of Carbine was made in July for control of aphids. This experiment will be conducted in varieties of sugarcane and energycane starting next season. This research work is a portion of the Ph.D. program of study by Matthew VanWeelden in the LSU Department of Entomology.

20 EFFECTINESS OF THE RED IMPORTED FIRE ANT IN REDUCING MEXICAN RICE BORER INJURY IN CONVENTIONAL AND BIOENERGY CROPPING SYSTEMS M.T. VanWeelden 1, B.E. Wilson 1, J.M Beuzelin 1, T.E. Reagan 1, and M.O. Way 3 1 LSU AgCenter, Department of Entomology 2 Texas A&M AgriLIFE Research and Extension Center, Beaumont, TX A study was conducted in 2012 at the Texas A&M AgriLIFE Research and Extension Center in Beaumont, TX to assess the effect of predation by the red imported fire ant, Solenopsis invicta, on field populations of Mexican rice borer (MRB), Eoreuma loftini. The experiment was arranged in a randomized complete block design with four replications. Each replication consisted of seven 3-row plots measuring 72 ft in length. The following seven varieties were randomized to plot: two sugarcanes (HoCP and HoCP ), two energycanes (L and Ho ), two high-biomass sorghums (ES 5200 and ES 5140), and one sweet sorghum (M81E). Pitfall traps were inserted into the center of each plot and contents were collected biweekly in order to estimate fire ant populations. To establish a heterogeneous distribution of ant populations, a granule bait insecticide consisting of hydromethylnon and S-methoprene was applied at random throughout the field. To determine total MRB injury at the end of the season, MRB injury (% bored internodes and no. of emergence holes) was recorded on 12 randomly selected plants (4 per row) from each plot using destructive sampling. The ratio of total emergence over percent bored internodes was calculated for each plot to determine relative survival of the MRB. The relationship between fire ant trap counts and MRB relative survival was analyzed for each variety using multiple linear regression (Proc Reg, SAS Institute). A relationship between fire ant trap counts and MRB relative survival was detected across all varieties (F=8.13; P<0.0001; R 2 =0.6329). Additionally, the impact of ants was found to be statistically significant (t=2.72; P=0.0103), decreasing relative survival of the MRB by a magnitude of 0.16 per 1 unit (fire ants) increase in trap counts. In the absence of fire ants, relative survival of the MRB ranged from %, with varieties of MRB-susceptible sugarcane (HoCP ) and energycane (L and HoCP ) expressing the highest and lowest levels of MRB survival, respectively. This data suggests that red imported fire ants have the potential to suppress MRB infestations in sugarcane, energycane, high-biomass sorghum, and sweet sorghum, however not at the extent as with the sugarcane borer, Diatraea saccharalis. In conjunction with MRB resistant cultivars, natural enemies can be used as an additional tool to mitigate crop losses against stalk boring pests. Additional studies will need to be conducted to determine more specifically the stages of MRB development which are at most risk to predation by fire ants, as well as the combined effects of other predators and parasitoids. This research work is a portion of the Ph.D. program of study by Matthew VanWeelden in the LSU Department of Entomology.

21 MANAGEMENT OF STALK BORERS IN RICE Mo Way, Becky Pearson, Caleb Verret and Suhas Vyavhare Texas A&M AgriLIFE Research and Extension Center, Beaumont, TX ---Mexican rice borer (MRB), sugarcane borer (SCB) and rice stalk borer attack Texas rice ---MRB now appears to be most abundant stalk borer attacking Texas rice First found in Texas Rice Belt in 1988; has since spread throughout the Texas Gulf Coast and now threatens rice and sugarcane industries in Louisiana ---Can capture moths in pheromone traps as soon as rice is planted, but little or no MRB activities in field until about panicle differentiation ---Avoid planting late ---Ratoon crop also vulnerable ---Lower cutting height of main crop can reduce populations and damage on ratoon crop ---Control grass weeds in and around field ---Certain areas of Texas Rice Belt (Jackson and Matagorda Counties) more prone to stalk borer damage, but other areas also vulnerable ---Encourage vigorous stand (thin stands and levee rice are vulnerable) ---Hybrids appear to be more resistant than inbreds (future research need) ---Apply pyrethroids at 1-2 inch panicle followed by another application at heading ---Use Dermacor X-100 seed treatment ---Control of stalk borers on main crop benefits both main and ratoon crops ---Bt rice effective FOR MORE INFORMATION SEE THE TEXAS RICE PRODUCTION GUIDELINES OR CONTACT MO WAY

22 EVALUATION OF INSECTICIDAL SEED STREATMENTS FOR CONTROL OF RICE WATER WEEVIL AND STALK BORERS IN EARLY PLANTED RICE, BEAUMONT, TX, 2012 North Mo Way, Becky Pearson, Caleb Verret and Suhas Vyavhare Texas A&M AgriLIFE Research and Extension Center, Beaumont, TX PLOT PLAN I II III IV Plot size: 7 rows, 7 inch row spacing, 18 ft long, with barriers on reps I and III Variety: CL162 (provided by Horizon Ag) and XP753 (provided by RiceTec) Note: smaller numbers in italics are plot numbers TREATMENT DESCRIPTIONS, RATES AND TIMINGS Treatment no. Variety Description Rate 1 CL162 Dermacor X-100 a 2.5 fl oz/cwt 2 CL162 Dermacor X-100 a 1.75 fl oz/a 3 CL162 CruiserMaxx Rice 7 fl oz/cwt 4 CL162 Untreated XP753 Dermacor X-100 a 4 fl oz/cwt 6 XP753 Dermacor X-100 a 5 fl oz/cwt 7 XP753 Dermacor X-100 a 1.75 fl oz/a 8 XP753 CruiserMaxx Rice 7 fl oz/cwt 9 XP753 Untreated --- a Also contains Maxim 0.30 µg ai/seed, Dynasty 1.50 µg ai/seed and Apron 1.90 µg ai/seed M.O. Way moway@aesrg.tamu.edu (409) ext.2231 Texas A & M AgriLife Research and Extension Center at Beaumont 1509 Aggie Dr. Beaumont, TX

23 Agronomic and Cultural Information Experimental design: Randomized complete block with 9 treatments and 4 replications Planting: Drill-planted 50 lb/a (CL162) and 20 lb/a (XP753) into League soil (ph 5.5, sand 3.2%, silt 32.4%, clay 64.4%, and organic matter %) on Apr 27 Plot size = 7 rows, 7 inch row spacing, 18 ft long with metal barriers on reps I and III Emergence on May 6 Irrigation: Flushed blocks (temporary flood for 48 hours, then drain) on Apr 29 Note: Plots were flushed as needed from emergence to permanent flood Permanent flood (PF) on May 26 (20 days after emergence) Fertilization: All fertilizer (urea) was distributed by hand. 34 lb N/A (20% of 170) on CL162 only on Apr 29 at planting 85.0 lb N/A (50% of 170) on CL162 on May 26 at PF 120 lb N/A on XP753 on May 26 at PF 51.0 lb N/A (30% of 170) on CL162 only on Jun 11 at panicle differentiation 60 lb N/A on XP753 on Jul 16 at late boot/early heading Herbicide: 1 oz/a, Command 1 pt/a and 3 qt/a applied with a 2-person hand-held spray boom ( nozzles, 50 mesh screens, 16 gpa final spray volume) on May 16 for early season weed control Treatments: All seed treatments applied by Entomology project on Apr 24 Sampling: Stand counts (3, 3 ft counts on rows 2, 4 and 6) on May 10 Vigor ratings on May 14; no signs of insect damage other than rice water weevil (RWW) feeding scars Vigor ratings on May 23; some phyto (possibly from herbicide) in all plots, seems worse in XP753 than in CL162 RWW cores (5 cores per plot, each core 4 inches diameter, 4 inches deep, containing at least one rice plant) were collected on Jun 19 and Jun 28. Core samples were stored in a cold room, later washed through 40 mesh screen buckets and immature RWW counted. Whiteheads (WHs) counted in 4 rows per plot on Jul 26; WHs are a measure of stalk borer activity. Harvest: Harvested all plots on Sep 14 Size harvested plot = 7 rows, 7 inch row spacing, 18 ft long Data analysis: RWW and WH counts transformed using x ; yields converted to 12% moisture; all data analyzed by ANOVA and means separated by LSD. M.O. Way moway@aesrg.tamu.edu (409) ext.2231 Texas A & M AgriLife Research and Extension Center at Beaumont 1509 Aggie Dr. Beaumont, TX

24 Rice plant stands were higher in CL162 than XP753 plots, as expected (Table 1). Within a variety, plant stands were not significantly different among treatments; thus, the seed treatments did not affect rice plant stands. Vigor ratings were lowest in the untreated, regardless of variety. So, in general, plants derived from treated seed appeared more robust than plants in untreated plots. Vigor ratings were somewhat subjective and included color, uniformity of stand and general appearance. RWW densities on the 1 st sample date were very high in untreated plots of both varieties (Table 2). However, untreated XP753 produced higher numbers of RWW compared to untreated CL161 which is not surprising because RWWs prefer thin to thick stands of rice. The lower rates of Dermacor X-100 performed as well as the higher rates for both varieties (seeding rates). Results were similar for the 2 nd sample date. CruiserMaxx Rice did not perform as well as Dermacor X-100, regardless of variety/seeding rate. In addition, for CL162, Dermacor X-100 rates significantly reduced WH densities. The majority of stalk borers were Mexican rice borer. No significant populations of other insects were observed during the course of the experiment. XP753 produced higher yields than CL162 across all treatments. For CL162, the average yield increase for the seed treatments compared to the untreated was more than 800 lb/a. For XP753, the average yield increase for the seed treatments compared to the untreated was more than 1,100 lb/a. Table 1: Mean stand and vigor data for Dermacor X-100 seed treatment rate study (early planting). Beaumont, TX, Stand Rate (plants/ft of Vigor rating (1 9) a Variety Treatment (fl oz/cwt) row) May 14 May 23 CL162 Dermacor X-100 b a 5.3 c 6.3 ab CL162 Dermacor X-100 b 1.75 fl oz/a 7.9 a 5.3 c 6.0 ab CL162 CruiserMaxx Rice a 6.8 a 6.8 a CL162 Untreated a 5.0 c 5.0 c XP753 Dermacor X-100 b b 5.3 c 6.0 ab XP753 Dermacor X-100 b b 5.0 c 5.8 bc XP753 Dermacor X-100 b 1.75 fl oz/a 3.8 b 5.3 c 5.5 bc XP753 CruiserMaxx Rice b 6.0 b 5.8 bc XP753 Untreated b 5.0 c 5.0 c a Scale of 1 9: 1 = visually and clearly inferior to untreated; 2 = significantly inferior; 3 = noticeably inferior; 4 = slightly inferior; 5 = equal to; 6 = slightly better; 7 = noticeably better; 8 = significantly better; and 9 = visually and clearly better than untreated. b Also contains Maxim 0.30 µg ai/seed, Dynasty 1.50 µg ai/seed and Apron 1.90 µg ai/seed Means in a column followed by the same letter are not significantly different (P = 0.05, ANOVA and LSD) M.O. Way moway@aesrg.tamu.edu (409) ext.2231 Texas A & M AgriLife Research and Extension Center at Beaumont 1509 Aggie Dr. Beaumont, TX

25 Table 2. Mean rice water weevil (RWW), whitehead and yield data for Dermacor X-100 seed treatment rate study. Beaumont, TX Rate RWW a / 5 cores WHs a /4 Yield Variety Treatment (fl oz/cwt) Jun 19 Jun 28 rows (lb/a) CL162 Dermacor X-100 b cd 2.5 d 0.0 c 6964 cd CL162 Dermacor X-100 b 1.75 fl oz/a 6.5 d 2.3 d 0.3 c 7238 c CL162 CruiserMaxx Rice bc 7.8 bcd 13.5 a 6953 cd CL162 Untreated a 21.8 a 6.5 b 6234 d XP753 Dermacor X-100 b cd 14.3 abc 0.0 c 9894 a XP753 Dermacor X-100 b cd 5.3 cd 0.3 c 9892 a XP753 Dermacor X-100 b 1.75 fl oz/a 5.0 d 3.3 d 0.0 c a XP753 CruiserMaxx Rice b 17.5 ab 0.0 c 9666 ab XP753 Untreated a 26.3 a 0.5 c 8794 b a RWW = rice water weevil; WH = whitehead b Also contains Maxim 0.30 µg ai/seed, Dynasty 1.50 µg ai/seed and Apron 1.90 µg ai/seed Means in a column followed by the same letter are not significantly different (P = 0.05, ANOVA and LSD) M.O. Way moway@aesrg.tamu.edu (409) ext.2231 Texas A & M AgriLife Research and Extension Center at Beaumont 1509 Aggie Dr. Beaumont, TX

26 EVAULUATION OF INSECTICIDAL SEED TREATMENTSA AND FOLIAR APLLICATIONS FOR CONTROL OF THE RICE WATER WEEVIL AND STALK BORERS IN WATER SEEDED RICE, BEAUMONT, TX, 2012 North Mo Way, Becky Pearson, Caleb Verret and Suhas Vyavhare Texas A&M AgriLIFE Research and Extension Center, Beaumont, TX PLOT PLAN I II III IV Plot size: 4 ft x 18 ft long, with barriers Variety: CL162 (provided by Horizon Ag) and Presidio (provided by TRIA) Note: smaller numbers in italics are plot numbers TREATMENT DESCRIPTIONS, RATES AND TIMINGS Rate Treatment no. Variety Description (fl oz/cwt) 1 Presidio Dermacor X Presidio Dermacor X Presidio Karate Z a 0.03 lb ai/a 4 CL162 Dermacor X CL162 Dermacor X CL162 Karate Z a 0.03 lb ai/a 7 CL162 Untreated Presidio Untreated --- a Karate Z foliar treatments applied 3 days after rice emergence through water M.O. Way moway@aesrg.tamu.edu (409) ext.2231 Texas A & M AgriLife Research and Extension Center at Beaumont 1509 Aggie Dr. Beaumont, TX

27 Agronomic and Cultural Information Experimental design: Randomized complete block with 8 treatments and 4 replications Planting: Irrigation: Broadcast 100lb/A, and 70 lb/a) by hand into flooded plots containing League soil (ph 5.5, sand 3.2%, silt 32.4%, clay 64.4%, and organic matter %) on May 31 Plot size = 4 ft x 18 ft long with metal barriers Emergence through water on Jun 9 Permanent flood (PF) on May 29 (continuous flood regime) Fertilization: All fertilizer (urea) was distributed by hand lb N/A (2/3 of 170) on May 29 at planting 56.7 lb N/A (1/3 of 170) on Jul 6 Herbicide: Treatments: 1.5 oz/a applied using a hand-held, CO 2 pressurized, 3 nozzle ( tips with 50 mesh screens, 29 gpa final spray volume) spray rig on Jul 2, for duck salad control Treatments 1, 2, 4 and 5 (Dermacor X-100 seed treatments) applied by the Entomology Project Treatments 3 and 6 (Karate Z foliar spray) applied using a hand-held, CO 2 pressurized, 3 nozzle ( tips with 50 mesh screens, 29 gpa final spray volume) spray rig on Jun 12 (3 days after emergence through water) Sampling: Floating seedlings removed and counted on Jun 11 Vigor ratings; no phyto noted; poor stand on south end of plot 29 on Jun 16 Vigor ratings; no phyto noted; poor stand on south end of plot 29 on Jun 22 5, 0.34ft 2 stand counts per plot on Jul 2 Vigor ratings; no phyto noted; poor stand on south end of plot 29 on Jul 3 Rice water weevil (RWW) cores (5 cores per plot, each core 4 inches diameter, 4 inches deep, containing at least one rice plant) were collected on Jul 2 and Jul 11. Core samples were stored in a cold room, later washed through 40 mesh screen buckets and immature RWW counted. Whiteheads (WHs) counted in each plot on Sep 3; WHs are a measure of stalk borer activity. Harvest: Harvested all plots on Sep 10 Size harvested plot = 4 ft wide, 18 ft long Data analysis: RWW and WH counts transformed using x ; yields converted to 12% moisture; all data analyzed by ANOVA and means separated by LSD M.O. Way moway@aesrg.tamu.edu (409) ext.2231 Texas A & M AgriLife Research and Extension Center at Beaumont 1509 Aggie Dr. Beaumont, TX

28 Dislodged seedlings (floaters) were observed in selected plots about the time of rice emergence through water. Previous research implicated a small aquatic beetle, Tropisternus lateralis, responsible for dislodging seedlings through foraging, feeding and reproductive activities. Other factors, such as wind and tadpole shrimp, also can cause uprooting of seedlings. However, tadpole shrimp do not occur in Texas rice paddies. Very high numbers of floaters were found in untreated and Karate Z-treated plots (Table 1). This suggests Dermacor X-100 seed treatments prevented T. lateralis from uprooting rice. The seed treatment probably killed populations of this aquatic insect. In addition, T. lateralis was observed in plots with an abundance of floaters. Karate Z treatments were probably not effective because applications were made at rice emergence through water. Prior to this time, seedlings were probably uprooted by T. lateralis. Although the number of floaters was significantly different among treatments, rice plant stands were not. Vigor ratings were visual and based on color, height, uniformity and general plant health. The most vigorous appearing plot in a replication was assigned a vigor rating of 9; all other plots in this replication were rated relative to the highest rated plot. Vigor ratings were similar among treatments 7 days after rice emergence through water. However, 13 and 23 days after rice emergence through water, generally, untreated plots of both varieties exhibited the least vigor. Due to the late planting date, RWW populations were relatively low in untreated plots (Table 2). However, WH counts were very high in untreated plots of CL162. Data suggest CL162 is very susceptible to stalk borer damage. The majority of stalk borers were Mexican rice borer. Yields were relatively low throughout the experiment---again, due to the late planting date. In addition, Presidio produced higher yields than CL162 which may be due to lower stalk borer pressure in Presidio versus CL162. Table 1: Mean floater, vigor and stand data for Dermacor X-100 water-seeded study. Beaumont, TX, Rate Floaters/ Stand Vigor ratings (1 9) Variety Treatment (fl oz/cwt) plot (plants/ft 2 ) Jun 16 Jun 22 Jul 2 Presidio Dermacor X c 30.0 a a 9.0 a Presidio Dermacor X c Presidio Karate Z 0.03 lb ai/a a 30.8 a a 8.8 a 31.8 a a 8.5 ab CL162 Dermacor X c 21.6 b ab 8.5 ab CL162 Dermacor X c 21.1b b 8.0 ab CL162 Karate Z 0.03 lb ai/a ab 22.4 b a 8.8 a CL162 Untreated b 21.7 b ab 7.5 bc Presidio Untreated a 32.8 a 9.0 NS 8.5 ab 6.5 c Means in a column followed by the same or no letter are not significantly (NS) different (P = 0.05, ANOVA and LSD). M.O. Way moway@aesrg.tamu.edu (409) ext.2231 Texas A & M AgriLife Research and Extension Center at Beaumont 1509 Aggie Dr. Beaumont, TX

29 Table 2: Mean rice water weevil (RWW), whitehead and yield data for Dermacor X-100 waterseeded study. Beaumont, TX, Rate RWW/5 cores Yield Variety Treatment (fl oz/cwt) Jul 2 Jul 11 WHs/plot (lb/a) Presidio Dermacor X bc 7.5 c 5490 ab Presidio Dermacor X bc 5.3 c 5831 a Presidio Karate Z 0.03 lb ai/a a 10.5 c 5517 ab CL162 Dermacor X c 32.5 b 5316 abc CL162 Dermacor X ab 31.0 b 4983 abc CL162 Karate Z 0.03 lb ai/a bc 38.0 b 4877 abc CL162 Untreated bc 64.0 a 4311 c Presidio Untreated bc 8.5 c 4530 bc NS Means in a column followed by the same or no letter are not significantly (NS) different (P = 0.05, ANOVA and LSD). M.O. Way moway@aesrg.tamu.edu (409) ext.2231 Texas A & M AgriLife Research and Extension Center at Beaumont 1509 Aggie Dr. Beaumont, TX

30 THE EFFECT OF INTERTRAP DISTANCE ON THE PERFORMANCE OF MEXICAN RICE BORER PHEROMONE TRAPS B.E. Wilson 1, J.M. Beuzelin 1, M.T. VanWeelden 1, T.E. Reagan 1, and J. Allison 2 1 LSU AgCenter, Department of Entomology 2 Canadian Forestry Service (formerly LSU AgCenter) The Mexican rice borer (MRB), Eoreuma loftini, is an invasive stalk borer from Mexico which is expected to cause major economic losses to the sugarcane and rice crops in Louisiana. Traps baited with MRB female sex pheromone are effective tools to monitor range expansion and assist scouting for the pest in sugarcane. Traps are currently placed 10 parishes in Western Louisiana to monitor MRB populations. However, the attractive distance, or active space, remains unknown. The active space is the area downwind of a pheromone source over which males are able to detect and respond to the pheromone. A study was conducted in Oct Nov 2011 to assess the active space of pheromone traps by examining the effect of intertrap distance on the number of male MRB captured. The effect of intertrap distance was assessed with hexagonal arrays of pheromone traps with a single trap in the center (Figure 1). Arrays with intertrap distances of 5, 25, 50, 100 and 250 m were deployed in rice fields on two farms in Jefferson and Chambers Counties, TX, and the number of moths caught was recorded for all traps for 5 sampling periods for a total of 10 replications. The number of moths caught per trap/day and the proportion of moths caught by the center trap versus perimeter trap were analyzed using generalized linear mixed models (Proc Glimmix SAS 2008). Differences were detected between treatments (F = 16.9, P < ), with the greatest numbers of MRB caught in traps with an intertrap distance of 250 m (Table 1). The proportion of the total moths caught by center trap was lower than the average proportion caught in perimeter traps at 5, 25, and 50 m (F = 2.79, P = 0.027). Differences were not detected between the center and perimeter traps in the 100 and 250 m arrays (Table 2). Results indicate there is substantial interference between traps placed less than 100m apart. Reduced trap capture in the center trap relative to perimeter trap likely results from overlapping active spaces at low distances. Additionally, data suggest the active distance of E. loftini pheromone traps may be greater than 100 m. Based on these results, pheromone traps should be placed at least 250 m apart from in order to maximize trap performance. This experiment is being repeated in 2013 with revised distances of 50, 100, 150, 225, and 300 m. Figure 1: Hexagonal arrays of MRB pheromone traps. X = pheromone trap x = 5, 25, 50, 100, 250 meters This research work is a portion of the Ph.D. program of study by Blake Wilson in the LSU Department of Entomology..

31 Table 1: Average daily trap capture of MRB pheromone traps as affected by intertrap distance Intertrap Distance (m) MRB caught/trap/day A A A B C LS Means (± 1.1 [SE]). F= 16.9, df = 4,36, P< Means which share a letter are not significantly different (LSD, α=0.05). Table 2: The proportion of total MRB catch caught by center traps versus perimeter traps as affected by intertrap distance Intertrap Distance (m) Proportion of Total Array Catch Central Trap Perimeter Traps * * * LS Means. F= 2.79, df= 4, 293, P< *Central trap is significantly less than mean for perimeter traps (LSD, α=0.05). This research work is a portion of the Ph.D. program of study by Blake Wilson in the LSU Department of Entomology..

32 FIELD AND FORAGE CROPS Improved Chemical Control for the Mexican Rice Borer (Lepidoptera: Crambidae) in Sugarcane: Larval Exposure, a Novel Scouting Method, and Efficacy of a Single Aerial Insecticide Application B. E. WILSON, 1,2 A. T. SHOWLER, 3 T. E. REAGAN, 1 AND J. M. BEUZELIN 1 J. Econ. Entomol. 105(6): 1998Ð2006 (2012); DOI: ABSTRACT A three-treatment aerial application insecticide experiment was conducted in Þve commercial sugarcane, Saccharum spp., Þelds in south Texas to evaluate the use of pheromone traps for improving chemical control of the Mexican rice borer, Eoreuma loftini (Dyar), in 2009 and A threshold of 20 moths/trap/wk was used to initiate monitoring for larval infestations. The percentage of stalks with larvae on plant surfaces was directly related to the number of moths trapped. Reductions in borer injury and adult emergence were detected when a threshold of 5% of stalks with larvae present on plant surfaces was used to trigger insecticide applications. Novaluron provided superior control compared with -cyßuthrin; novaluron treated plots were associated with a 14% increase in sugar production. A greenhouse experiment investigating establishment and behavior of E. loftini larvae on two phenological stages of stalkborer resistant, HoCP , and susceptible, HoCP , sugarcane cultivars determined that more than half of larvae on HoCP and 25% on HoCP tunneled inside leaf mid-ribs within 1dofeclosion, protected therein from biological and chemical control tactics. Exposure time of larvae averaged 1 wk for all treatments and was shortest on immature HoCP and longest on mature HoCP This study shows a short window of vulnerability of E. loftini larvae to insecticide applications, and demonstrates the potential utility of pheromone traps for improving insecticide intervention timing such that a single properly timed application may be all that is required. KEY WORDS Eoreuma loftini, novaluron, chemical control, neonate, sugarcane The Mexican rice borer, Eoreuma loftini (Dyar), is an invasive crambid originating in Mexico, Þrst detected in south Texas in 1980 (Johnson and Van Leerdam 1981). Now the pest comprises 95% of the sugarcane, Saccharum spp., stalkborer population there (Legaspi et al. 1997) and causes $10 million in annual revenue losses (Legaspi et al. 1999). The insect has expanded into the rice (Oryza sativa L.), production area of east Texas (Browning et al. 1989, ReayÐJones et al. 2007a), and, recently, Louisiana (Hummel et al. 2010). By 2035, E. loftini is predicted to infest all of LouisianaÕs sugarcane areas with projected annual losses of $220 million in sugarcane and $48 million in rice (ReayÐ Jones et al. 2008). Insecticidal control of E. loftini has rarely improved sugarcane yield (Johnson 1985, Meagher et al. 1994, ReayÐJones et al. 2005), and south Texas growers have Mention of trade names or commercial products in this publication is solely for the purpose of providing speciþc information and does not imply recommendation or endorsement by the US. Department of Agriculture. 1 Department of Entomology, 404 Life Sciences Building, LSU Campus, Baton Rouge, LA Corresponding author, bwilson@agcenter.lsu.edu. 3 Kika de la Garza Subtropical Agricultural Research Center, USDAÐARS, 2413 E. Highway 83, Weslaco, TX largely abandoned the tactic (Legaspi et al. 1997). However, a recently developed insect growth regulator (IGR), novaluron, suppresses E. loftini infestations in sugarcane (Akbar et al. 2009). Modeled after the sugarcane borer, Diatraea saccharalis (F.), intervention threshold in Louisiana (Hensley 1971, Posey et al. 2006), a threshold of 5% of stalks with E. loftini larvae on plant surfaces indicates the need for an insecticide application (Johnson 1985). Scouting for E. loftini in sugarcane is labor intensive and identiþcation of a relationship between adult population density and larval infestations could improve early detection of population increases (Meagher et al. 1996). Pheromone traps are effective at monitoring adult male E. loftini populations (Shaver et al. 1990, 1991; Reagan et al. 2001) and could be useful for determining insecticide application timing. Chemical control of E. loftini is hindered by the larvae boring into stalks and packing tunnels with protective frass. Hence, insecticide applications target early instars that are exposed on plant surfaces (Johnson 1985, Van Leerdam 1986, Meagher et al. 1994). E. loftini prefers to oviposit in folds that mostly occur on dry leaf material (Showler and Castro 2010b), protected from insecticides and natural enemies. After eclosion, early instars disperse and feed on the green

33 December 2012 WILSON ET AL.: Eoreuma loftini MANAGEMENT IN SUGARCANE 1999 tissue of leaves and leaf sheaths before they enter the stalk (Van Leerdam 1986). Van Leerdam (1986) estimated 10 d between eclosion and stalk entry, the average age of third instars reared at 29 C. Resistant cultivars might be able to extend the intervention window, hence increasing potential efþcacy of insecticides. Because larvae are protected once they bore into the stalk, the period of exposure while feeding on leaves and sheaths is the only time larvae are vulnerable to control tactics. Determination of duration of larval vulnerability will have broad implications to E. loftini integrated pest management (IPM), including re- Þning the economic threshold (based on scouting for exposed larvae), developing cultivar-speciþc intervention thresholds (Posey et al. 2006, White et al. 2008) and identifying resistance mechanisms. The objectives of this study were 1) to assess the efþcacy of an IGR application under commercial conditions, triggered by E. loftini population monitoring with pheromone traps; 2) to determine the pestõs window of larval exposure to insecticides; and 3) to assess effects of sugarcane cultivar and phenological stage on early instar feeding behavior and establishment. Materials and Methods Aerial Insecticidal Control. A Þeld study was conducted in 2009 and 2010 using a randomized complete block design, each of the Þve blocks (replications) being a 14Ð33 ha commercial sugarcane Þeld (variety CP ) in Cameron and Hidalgo counties, TX. Each Þeld had three 4-ha plots for a nontreated control, and threshold-triggered applications of novaluron (Diamond 0.83 EC; Makhteshim Agan of North America Inc., Raleigh, NC) at 80 g (active ingredient [AI])/ha or -cyßuthrin (Baythroid XL; Bayer Crop- Science, Research Triangle Park, NC) at 25 g (AI/ha). Adult E. loftini population densities were monitored using standard universal pheromone traps (Unitrap; Great Lakes IPM, Vestaburg, MI) (one per Þeld in 2009, two per Þeld in 2010) baited with synthetic E. loftini female sex pheromone in a rubber septa lure (Luresept; Hercon Environmental, Emigsville, PA). Traps were attached to metal poles 1 m above the soil surface 2 m inside the sugarcane Þelds, each trap containing an insecticidal strip (Vaportape II; Hercon Environmental, Emigsville, PA) to maximize trap capture (Shaver et al. 1991). Pheromone lures were replaced every 2 wk and insecticidal strips were replaced every 4 wk according to label instructions. Traps were checked weekly from 15 July to 14 October 2009 and from 1 June to 14 August 2010, and numbers of captured male E. loftini were recorded. In 2009, a threshold of 20 moths per trap per week was developed based on preliminary reports (Reagan et al. 2001) and Þeld observations (T. E. Reagan, personal observations). Trap catches exceeding this threshold initiated visual monitoring for larval infestations, by removing all leaf sheaths and recording the presence of larvae on 20 randomly selected stalks per Þeld. Larval monitoring was expanded in 2010 being conducted throughout the growing season by examination of 10 stalks (1 June through 6 July) or 20 stalks (13 July through 14 August) several rows in from trap locations in all Þelds. Larval infestations exceeding the threshold of 5% of stalks with exposed larvae present on plant surfaces triggered insecticide applications by a Þxed wing aircraft ßying at 233 km/h equipped with CP-03 nozzles at 96 L/ha ( 8 km/h wind) on the mornings of 21 August 2009 and 14 August Before harvest, 15-stalk samples were collected on 28 October 2009 and 8 November 2010 from two locations in each plot and the numbers of internodes, bored internodes, and moth emergence holes were recorded. Plots were harvested separately using conventional farm equipment and the sugarcane was weighed. Tons of sugarcane per hectare (TCH) was calculated by dividing the total weight of sugarcane (tons) harvested from each plot by the plot size (hectares). Sugarcane yield and quality parameters were calculated by the Rio Grande Valley Sugar Growers laboratory with the core sampling method (Birkett 1975, 1979) including percentage brix and percentage sucrose determined though direct polarization. The ratio of sucrose to all other dissolved solids, or juice purity, is expressed as a percentage. Commercially recoverable sugar (CRS) was recorded for each core sample and extrapolated to one ton of cane that is expressed as pounds of sugar per ton of sugarcane. TSH was calculated by the following: TSH (Mean CRS*TCH)/2000. Yield data were analyzed using generalized linear mixed models (Proc GLIMMIX; SAS Institute 2008) with Gaussian distributions. Means were converted to metric units after analysis. Yield data were only collected in The unavailability of 2009 yield and quality data resulted from a rush by growers to harvest because of hard freezes and rapid crop deterioration in December 2009 and January The numbers of internodes, bored internodes, and emergence holes from stalks were summed for each 15-stalk sample to reduce effects of inter-stalk variation. Data were analyzed with year, Þeld, Þeld year, and Þeld year treatment as random effects. The proportion of bored internodes was analyzed using a generalized linear mixed model (Proc GLIMMIX; SAS Institute 2008) with a binomial distribution. Numbers of adult emergence holes were analyzed using a generalized linear mixed model (Proc GLIMMIX; SAS Institute 2008) with a Poisson distribution. Generalized linear mixed models with appropriate distributions were used (PROC GLIMMIX; SAS Institute 2008) because proportion data (percentage of bored internodes) and count data (number of emergence holes) are not normally distributed. For all models, the KenwardÐRoger method (Kenward and Roger 1997) was used to compute denominator degrees of freedom for the test of Þxed effects for all variables, and TukeyÕs honestly signiþcant difference (HSD) test (Tukey 1953) was used for mean separation. In addition, a simple linear regression between the numbers of male E. loftini per pheromone trap per week and the percentages of stalks infested with treatable larvae in 2010 was conducted (Proc GLIMMIX; SAS Institute 2008).

34 2000 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 105, no. 6 Early Instar Establishment and Behavior. A greenhouse study was conducted during the summer of 2010 at the U.S. Department of AgricultureÐAgriculture Research Services (USDAÐARS) Kika de la Garza Subtropical Agricultural Research Center, Weslaco, TX, to investigate E. loftini early instar establishment and feeding behavior on two phenological stages of an E. loftini resistant sugarcane cultivar, HoCP , and a susceptible cultivar, HoCP (ReayÐJones et al. 2005). Twenty-four sugarcane nodes of each cultivar were obtained from Certis U.S.A. (Baton Rouge, LA) sugarcane tissue cultures. All nodes were planted in mid May in 7.6-liter pots in Sunshine mix no. 1 nursery potting soil ( 75% sphagnum peat moss, perlite, dolomitic limestone, and gypsum; Sungro Horticulture, Bellevue, WA). Plants were kept well watered throughout their growth and 200 ml of Peters Professional (ScottsÐSierra Horticulture Products Company, Marysville, OH) water-soluble general purpose fertilizer was applied to the soil once plants reached the two-leaf stage. Plants were arranged in a completely randomized design as a 2 2 factorial, cultivar phenological stage, with each of the four treatments replicated using 12 stalks. The experiment was initiated when stalks had produced six nodes (immature sugarcane) from 14 June through 2 July, and from 30 July through 17 August when stalks had 12 nodes (mature sugarcane). Eggs were obtained from a laboratory colony reared from E. loftini larvae collected from commercial sugarcane Þelds in Hidalgo Co., TX, on artiþcial diet (Martinez et al. 1988) at 25 C, 65% relative humidity (RH), and a photoperiod of 14:10 (L:D) h. After mating, E. loftini females deposited egg masses of 10Ð80 eggs on 1-cm wide paper strips. Before attaching strips using 2.5-cm paper clips to the ventral side of leaves 15Ð25 cm from the stalk, eggs on each strip were counted. The paper strips were removed 7 d later after eggs hatched and the numbers of unhatched, presumably nonviable, eggs were counted under a microscope. Over all treatments and replications, development and behavior of 277 early instars was examined by direct observation and stalk dissection. On day 1 after egg hatch, numerous entry holes in the mid-rib of sugarcane leaves were observed indicating neonates had bored into leaves with in 1 d of hatching rather than feeding in leaf sheaths as anticipated. The location of initial establishment was recorded as either sheath feeding or mid-rib entry, and numbers and positions of mid-rib entry holes were recorded. All leaves and leaf sheaths on each plant were examined daily over 14 consecutive days for the presence of early instar E. loftini, and the location of feeding sites (mid-rib or sheath), dispersal distance from oviposition sites, and time to stalk entry were recorded. The percentage of larvae that became established on each stalk was based on the number of larvae observed feeding on or in leaves and leaf sheaths out of the number of hatched eggs. Dispersal of early instars, expressed as number of internodes traversed from oviposition sites, was recorded for all established larvae. Early instars feeding within the leaf sheaths were monitored daily by checking between the stalk and leaf sheath for the presence of larvae. Daily examination of each sheath was conducted until entry holes were observed or larvae were recorded as dead or vanished. Survival to stalk entry and duration of leaf sheath feeding (time from eclosion to mid-rib or stalk entry) were recorded. After allowing 4 wk for development, stalks were dissected and the numbers and locations of entry holes and live larvae and pupae were recorded. The proportion of larvae that became established on the stalk and the proportions entering leaf mid-ribs and surviving to stalk entry were not transformed and were analyzed using generalized linear mixed models (Proc GLIMMIX; SAS Institute 2008) with binomial distributions. A separate analysis that excluded larvae that had entered into the mid-rib compared effects of treatments on duration of leaf sheath feeding. A linear mixed model (Proc GLIMMIX; SAS Institute 2008) was used to analyze data on the duration of exposure, duration of leaf-sheath feeding, and larval dispersal. Results Aerial Insecticidal Control. Pheromone trap captures in both 2009 and 2010 peaked in late August (Fig. 1). Larval infestations ranged from 5 to 32% with a mean of % of stalks with treatable larvae present on plant surfaces on 20 August 2009, a day before insecticide applications. A steady decline in the mean number E. loftini per trap per week occurred in September and October after the 21 August 2009 insecticide application (Fig. 1). On 14 August 2010 larval infestations ranged from 5 to 22.5% with a mean of % of stalks with larvae exposed on plant surfaces. Weekly monitoring of larval infestations in 2010 allowed for determination of the relationship between adult population density and larval infestation (Fig. 2). Linear regression revealed a relationship (F 280.7; df 1, 114; P ; R ) between pheromone trap catches and larval infestation that can be summarized by the equation, y 0.213x Ð 0.038, where x is the number of E. loftini per trap per week and y is the percentage of stalks infested with treatable larvae feeding on plant surfaces. The probability of occurrence of a bored internode was reduced compared with nontreated controls by an average of 40.3 and 60.2% over both years in -cyßuthrin and novaluron treated plots, respectively (F 11.41; df 2, 18.2; P ) (Fig. 3A). The mean numbers of emergence holes per stalk were 37.4 and 58.4% lower than nontreated controls over both years for -cyßuthrin and novaluron treated plots, respectively (F 4.65; df 2, 17.2; P ) (Fig. 3B). Yield data from 2010 indicate that reduced injury in novaluron treated plots was associated with improved juice purity by 1%, percentage sucrose by 3.5%, percentage brix by 3%, sugar per metric ton of sugarcane by 5.3%, metric tons of sugarcane per hectare by 8.8%, and recoverable sugar (metric tons of sugar per hectare) by 14% (Table 1) compared with untreated controls. -cyßuthrin treated plots were only different

35 December 2012 WILSON ET AL.: Eoreuma loftini MANAGEMENT IN SUGARCANE 2001 Fig. 1. Pheromone trap monitoring of E. loftini in Hidalgo and Cameron Counties, TX. (A) Average no. of E. loftini per trap per week ( SE) from 15 July to 14 October 2009; (B) Average no. of E. loftini per trap per week ( SE) from 1 June to 10 August from controls in terms of sugar yield per metric ton of sugarcane (2.6% increase). Early Instar Establishment and Behavior. On the Þrst day after egg hatch, numerous entry holes in the mid-ribs of sugarcane leaves were observed, indicating that 24.1 to 67.5% of early instars had bored into leaves within 1 d of hatching (Table 2). The mean percentage of larvae surviving to stalk entry ranged from 27.4 to 72.4% among treatments, and mean duration of exposure ranged from 3.5 to 6.4 d (Table 2). Over both phenological stages of sugarcane, the percentage of early instars that became established on the plant was 40% greater on susceptible cultivar HoCP than on resistant HoCP (Table 2). The percentage of established larvae that bored into the leaf mid-rib was twice as high on HoCP as on HoCP (Table 2). Average dispersal distance (numbers of internodes from oviposition sites) was 19% greater on HoCP than on HoCP (Table 2). Duration of exposure of all established larvae was 40% longer on HoCP than HoCP Duration of leaf sheath feeding was 14.7% longer in HoCP compared with HoCP when considering only established larvae feeding in leaf sheaths (Table 2). Fig. 2. Relationship between adult population densities (number of E. loftini per trap per week) and larval infestation (percent of stalks infested with treatable larvae feeding in leaf sheaths), 2010.

36 2002 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 105, no. 6 entering the mid-rib within 1 d and a mean duration of exposure of only 3.5 d (Table 2). Duration of larval exposure was longest, 6.4 d, on mature HoCP Fig. 3. E. loftini injury, sugarcane aerial insecticide application experiment in Cameron and Hidalgo Counties, TX, 2009 and (A) LS mean ( SE) percentage of E. loftini bored internodes; (B) LS mean ( SE) no. moth emergence holes per stalk. Bars within each chart followed by the same letter are not signiþcantly different (P 0.05; TukeyÕs HSD). The percentage of larvae to become established feeding in leaves and leaf sheaths was 60% greater on mature than on immature plants, and the percentage of established larvae surviving to stalk entry was 90% greater on immature than on mature sugarcane. Average dispersal distance was 30% greater on immature than on mature sugarcane (Table 2). All dispersal on immature sugarcane was toward the top of the stalk while 21% of larvae moved down from oviposition sites on mature sugarcane. Duration of exposure was 20% greater on mature plants than immature, and an interaction effect was detected between cultivar and phenological stage for the percentage of early instars entering the mid-rib and the percentage of established larvae surviving to stalk entry (Table 2). Immature HoCP had the greatest percentage of larvae Discussion Use of pheromone traps to assist scouting for E. loftini in sugarcane demonstrates potential to reduce scouting effort and improve chemical control. A scouting threshold based on pheromone trap captures could enhance scouting efþciency by focusing larval monitoring at the most appropriate times when adult population densities are high. When a threshold of 20 E. loftini per trap per week was used (Reagan et al. 2001, T. E. Reagan, personal observations) only one instance of larval scouting was necessary in Weekly larval scouting from June to mid-august in 2010 revealed a strong positive relationship between numbers of E. loftini per trap per week and the percentage of stalks infested with treatable larvae on plant surfaces. Linear regression analysis indicated a trap catch of 23.6 E. loftini per trap per week corresponds to the treatment threshold of 5% of stalks infested with treatable larvae. These results indicate an action threshold of 20 E. loftini per trap per week is appropriate to initiate scouting and verify larval infestations. However, further evaluation of the relationship between larval infestations and pheromone trap captures under a variety of environmental conditions may be needed before this approach is extensively used. Therefore, pheromone trap assisted scouting could potentially be further developed for use on a broad commercial scale to increase monitoring efþciency in Texas and Louisiana. LouisianaÕs sugarcane industry is heavily dependent on consultant scouting for D. saccharalis infestations, and the infrastructure is in place to use pheromone trap assisted scouting when E. loftini becomes established as a major economic pest in Louisiana sugarcane (ReayÐJones et al. 2008, Hummel et al. 2010). When timed in accordance with our threshold, a single insecticide application reduced E. loftini injury and adult emergence in both 2009 and The superior control of novaluron in comparison to -cyßuthrin is likely the result of both residual and translaminar activity (Ishaaya et al. 2002, 2003), and conservation of beneþcial arthropods (Beuzelin et al. 2010). Novaluron has substantial residual and translaminar activity remaining effective for up to 5 wk Table 1. Sugar yield and quality (LS means SE) as affected by insecticide treatments, Cameron and Hidalgo Counties, TX, 2010 Purity POL (% sucrose) % brix Sugar (kg/metric ton of sugarcane) Cane (metric ton/ha) Sugar (metric ton/ha) Novaluron a a a a a a Baythroid ab b b b b b Control b b b c ab ab F 4.15 a a 7.47 a a 5.60 b 6.78 b P F Means in same column that share the same letter are not signiþcantly different (P 0.05; TukeyÕs HSD). a df 2, 124. b df 2, 8.

37 December 2012 WILSON ET AL.: Eoreuma loftini MANAGEMENT IN SUGARCANE 2003 Table 2. E. loftini neonate establishment and behavior on two phenological growth stages of sugarcane cultivars HoCP (resistant) and HoCP (susceptible), Weslaco, TX, 2010 Eclosed larvae established (%) Established larvae entering mid-rib within 1d(%) Established larvae surviving to stalk entry (%) Dispersal distance (nodes from oviposition site) Duration of exposure (d) All established larvae Established larvae in leaf sheaths Growth stage Immature Mature F a 0.91 a a 1.81 b 4.23 c d P F Cultivar HoCP HoCP F 5.08 a a 0.06 a 0.99 b 9.13 c 9.73 d P F Growth stage cultivar Immature HoCP HoCP Mature HoCP HoCP F 0.28 a 5.42 a 5.08 a 2.65 b 1.65 c 3.01 d P F a df 1, 44. b df 1, 159; considers all larvae. c df 1, 127; considers all larvae surviving until stalk entry. d df 1, 85; considers leaf sheath-feeding larvae that survived until stalk entry. depending on environmental conditions (Ishaaya et al. 2002, 2003; Cutler et al. 2005). -cyßuthrin has a longer residual activity, relative to other pyrethroids (Athanassiou et al. 2004), but its residual activity is negatively correlated with temperature and toxicity is greatly reduced at temperatures exceeding 25 C (Arthur 1999). The negative relationship between pyrethroid residual activity and temperature (Toth and Sparks 1990) might be an important factor limiting pyrethroid efþcacy in south Texas where summer temperatures regularly exceed 35 C. Novaluron and other IGRs are generally less toxic to nontarget arthropods than pyrethroid insecticides, better preserving natural pest suppression (Reagan and Posey 2001, Beuzelin et al. 2010). Reduced predation in -cyßuthrin treated plots might have contributed to weaker control relative to novaluron treated plots. Previous studies have shown that chemical control of E. loftini is inadequate to improve sugarcane yield even after multiple insecticide applications (Johnson 1985, Meagher et al. 1994, Legaspi et al. 1997, ReayÐ Jones et al. 2005). However, our study indicates that much of the difþculty might have been in part because of relatively poor timing of insecticide applications. The economics of E. loftini management using insecticides could be improved by reduction of multiple applications that are inefþcient, and relying more on a single well-timed insecticide application that increases yield. While yield data were only collected for 1 yr, the reduced yield loss detected in 2010 is consistent with the 2 yr of injury data (proportion of bored internodes) presented. The relationship between borer injury and yield is well established (Metcalfe 1969, White and Hensley 1987, Legaspi et al. 1999, White et al. 2008, ReayÐJones et al. 2008). Yield and quality parameters such as sugar per hectare, juice purity, and sucrose content have been documented as being inversely related to percentage of E. loftini bored internodes (Legaspi et al. 1999). We suggest that past failures to detect improved yields despite chemically induced reductions in percentages of bored internodes (Johnson 1985, Meagher et al. 1994, Legaspi et al. 1999, ReayÐJones et al. 2005) resulted from high variability in sugarcane yield studies, particularly involving small plot tests. Our experiment was the Þrst to adequately replicate larger areas (4 ha per treatment plot with Þve replications) and likely provides a more accurate assessment of insecticide application effects on sugar yield and quality under commercial conditions. A single application of novaluron enhanced subsequent sugar yield by 14% compared with controls in 2010, and based on the current price of raw sugar, $766.77/metric ton (U.S. Dep. Agric.ÐERS 2011), the novaluron treatment is expected to increase revenue by $690.09/ha, representing the Þrst report of insecticidal E. loftini control resulting in increased sugar yield and quality. Based on an aerial application cost with 95 L/ha of $37.50/ha (Salassi and Deliberto 2009) and the retail cost of novaluron of $30.00/ha the net economic beneþt of the application was $622.59/ha. However, because only 1 yr of yield data were collected in this study, insecticide effects on yield will require further evaluation. The importance of application timing and development of management tactics that target early instars is further supported by greenhouse research that suggests the duration of larval exposure on plant surfaces is substantially shorter than previously estimated (Van Leerdam 1986, Ring et al. 1991). Because larvae are protected once they bore into the stalk, the period of

38 2004 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 105, no. 6 exposure while feeding on leaves and sheaths is the only time larvae are vulnerable to control tactics. Determination of duration of larval vulnerability will have broad implications to E. loftini IPM, including reþning the economic threshold (based on scouting for exposed larvae), developing cultivar-speciþc intervention thresholds (Posey et al. 2006, White et al. 2008) and identifying host plant resistance mechanisms. The rapid entry of most E. loftini larvae into susceptible sugarcane (1 d) is substantially shorter than the 10 d reported by Van Leerdam (1986). In our study, early instar entry into the mid-ribs was recorded, and the appearance of entry holes in the stalks suggests these larvae also successfully entered the stalk with limited exposure on plant surfaces. Similar to E. loftini, the unsatisfactory performance of insecticides against Eldana saccharina (Walker) in South Africa (Heathcote 1984) might be because 5% of larvae bore into sugarcane plant surfaces within 1 d (Leslie 1993). Our research shows this behavior is relatively more frequent in E. loftini, and is likely an important factor limiting the success of chemical control. Differences in larval behavior between cultivars suggest that resistant varieties impede larval establishment with the potential to improve efþcacy of other control tactics. A greater percentage of larvae to become established feeding in leaves or leaf sheaths on susceptible HoCP than on the resistant HoCP occurred because more larvae bored into the plant within 1 d. Longer larval exposure on the resistant cultivar might be partly because of greater dispersal on the resistant cultivar than on the susceptible cultivar. The lack of differences in the percentage of established larvae to enter the stalk between cultivars suggests the mechanism of resistance such as leaf sheath appression (Coburn and Hensley 1972) occurred before stalk entry. Less space available on young sugarcane, particularly the lesser amount of folded leaf tissue, might have limited larval establishment (Showler and Castro 2010b). Once established, larval survival to stalk entry on immature sugarcane was nearly twice as great as that on mature sugarcane indicating young internodes are more susceptible to borer entry. Although more larvae became established feeding on the leaves and sheaths of mature sugarcane plants, proportionately fewer successfully entered the stalk relative to immature sugarcane possibly because immature sugarcane plants have greater nutritional value than mature sugarcane plants (ReayÐJones et al. 2007b). Further, the longer exposure on mature sugarcane plants suggests that physiological factors, such as increased rind hardness (Martin et al. 1975), of mature sugarcane impedes stalk boring (Van Leerdam 1986, Ring et al. 1991). Similarly, D. saccharalis establishment on corn plant surfaces infested at later growth stages is greater than on younger corn attributable to decreased leaf sheath appression as plants age, while larval stalk entry was greater on younger corn (Flynn et al. 1984). Host plant characteristics unfavorable to larval establishment are important components of host plant resistance to stalkborers (Mathes and Charpentier 1969), and resistance mechanisms that prolong larval exposure outside the stalk enhance the efþcacy of other control tactics including insecticide applications and biological control. Research has consistently shown that the greatest suppression of sugarcane stalkborer infestations is achieved when insecticide applications are used in conjunction with host plant resistance (Bessin et al. 1990b, ReayÐJones et al. 2005, Posey et al. 2006). Rapid early instar entry into the mid-rib suggests that E. loftini larvae are only brießy exposed to foliar applied contact insecticides. Hence, longer residual activity of insecticides will likely contribute to improved control. The residual and translaminar activity of novaluron (Ishaaya et al. 2002, 2003) is likely responsible for the superior control observed in our Þeld study. Elements of potential control strategies highlighted by this research include the use of pheromone traps to assist scouting and substantially improve application timing, increased residual activity of insecticides, and resistant cultivars that impede larval entry into the stalk. In Louisiana E. loftini is expected to inßict substantial revenue losses (ReayÐJones et al. 2008), and the need to develop management strategies is becoming urgent. In addition to reducing injury and increasing yield, control tactics that reduce adult emergence could aid in managing area-wide populations (Bessin et al. 1990a) and slow the expansion of this invasive pest. Our Þndings on a new monitoring method, an intervention threshold, insecticide efþcacy, and early instar behavior relative to varietal resistance and sugarcane plant phenology all contribute, in addition to providing suitable irrigation and avoidance of soil salinity (ReayÐJones et al. 2005, Showler and Castro 2010a), toward the advancement of increasingly effective E. loftini IPM. Acknowledgments The authors express appreciation to Jaime Cavazos and Veronica Abrigo (USDAÐARS Kika de la Garza, Subtropical Agricultural Research Center, Weslaco, TX), Sebe Brown (LSU AgCenter, Baton Rouge, LA), and Waseem Akbar (formerly LSU AgCenter) for technical assistance. Additional thanks are expressed to Jim Trolinger, Tony Prado, and Rio Grande Valley Sugar Growers Inc. for continuous support and collection of yield and quality data. We also thank commercial sugarcane growers with S.R.S. farms and Har- Vest for their cooperation. Appreciation is expressed to Jeff Flynn of Certis U.S.A. for providing sugarcane cultivars. Gratitude is expressed to David Blouin (LSU AgCenter) for statistical consulting. This work was supported in part by grants from the USDA (National Institute of Food and Agriculture) Crops at Risk Program ( ), the EPA Strategic Agricultural Initiative Program ( ), and the American Sugar Cane League. This paper is approved by the Director of the Louisiana Agricultural Experiment Station as manuscript no References Cited Akbar, W., J. M. Beuzelin, and T. E. Reagan Chemical control of the Mexican rice borer in the Lower Rio Grande Valley of Texas, Arthro. Manag. Tests 34: F70.

39 December 2012 WILSON ET AL.: Eoreuma loftini MANAGEMENT IN SUGARCANE 2005 Arthur, F Effect of temperature on residual activity of Cyßuthrin wettable powder. J. Econ. Entomol. 93: 695Ð699. Athanassiou, C. G., N. G. Kavallieratos, B. J. Vayias, C. B. Dimizas, A. S. Papagregoriou, and C. T. Buchelos Residual toxicity of beta-cyßuthrin, alpha-cypermethrin, and deltamethrin against Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) on stored wheat. Appl. Entomol. Zool. 39: 195Ð202. Bessin, R. T., T. E. Reagan, and F. A. Martin. 1990a. A moth production index for evaluating sugarcane resistance to the sugarcane borer (Lepidoptera: Pyralidae). J. Econ. Entomol. 83: 221Ð225. Bessin, R. T., T. E. Reagan, and E. B. Moser. 1990b. Integration of control tactics for the sugarcane borer (Lepidoptera: Pyralidae) in Louisiana sugarcane. J. Econ. Entomol. 83: 1563Ð1569. Beuzelin, J. M., W. Akbar, A. Mészáros, F.P.F. Reay Jones, and T. E. Reagan Field assessment of novaluron for sugarcane borer, Diatraea saccharalis (F.) (Lepidoptera: Crambidae), management in Louisiana sugarcane. Crop Prot. 29: 1168Ð1176. Birkett, H. S Preliminary report on the 1974 factory scale core studies. Proc. Am. Soc. Sugar Cane Technol. 5: 202Ð207. Birkett, H. S Observations on the Louisiana core samplers. Proc. Am. Soc. Sugar Cane Technol. 9: 93Ð95. Browning, H. W., M. O. Way, and B. M. Drees Managing the Mexican rice borer in Texas. Tex. Agric. Exp. Stn. B Coburn, G. E., and S. D. Hensley Differential survival of Diatraea saccharalis (F.) larvae on 2 varieties of sugarcane. Proc. Int. Soc. Sugar Cane Technol. 14: 440Ð444. Cutler, G. C., J. H. Tolman, C. D. Scott Dupree, and C. R. Harris Resistance potential of the Colorado potato beetle (Coleoptera: Chrysomelidae) to novaluron. J. Econ. Entomol. 98: 1685Ð1693. Flynn, J. L., T. E. Reagan, and E. O. Ogunwolu Establishment and damage of the sugarcane borer (Lepidoptera: Pyralidae) in corn as inßuenced by development. J. Econ. Entomol. 77: 691Ð697. Heathcote, R. J Insecticide testing against Eldana saccharina Walker. Proc. S. Afr. Sug. Technol. Assn. 58: 154Ð158. Hensley, S. D Management of sugarcane borer populations in Louisiana, a decade of change. Entomophaga 16: 133Ð146. Hummel, N. A., T. Hardy, T. E. Reagan, D. K. Pollet, C. E. Carlton, M. J. Stout, J. M. Beuzelin, W. Akbar, and W. H. White Monitoring and Þrst discovery of the Mexican rice borer Eoreuma loftini (Lepidoptera: Crambidae) in Louisiana. Fla. Entomol. 93: 123Ð124. Ishaaya, I., A. R. Horowitz, L. Tirry, and A. Barazani Novaluron (Rimon), a novel IGR: mechanism, selectivity and importance in IPM programs. Proc. Int. Symp. Crop. Protect. Med. Fac. Landbouww Univ. Gent. 67: 617Ð626. Ishaaya, I., S. Kontsedalov, and A. R. Horowitz Novaluron (Rimon), a novel IGR: potency and cross-resistance. Arch. Insect Biochem. Physiol. 54: 157Ð164. Johnson, K.J.R Seasonal occurrence and insecticidal suppression of Eoreuma loftini (Lepidoptera: Pyralidae) in sugarcane. J. Econ. Entomol. 78: 960Ð966. Johnson, K.J.R., and M. B. Van Leerdam Range extension of Acigona loftini into the Lower Rio Grande Valley of Texas. Sugar y Azucar. 76: 34. Kenward, M. H., and J. H. Roger Small sample inference for Þxed effects from restricted maximum likelihood. Biometrics 53: 983Ð997. Legaspi, J. C., B. C. Legaspi, Jr., E. G. King, and R. R. Saldaña Mexican rice borer, Eoreuma loftini (Lepidoptera: Pyralidae) in the Lower Rio Grande Valley of Texas: its history and control. Subtrop. Plant Sci. 49: 53Ð64. Legaspi, J. C., B. C. Legaspi, Jr., J. E. Irvine, J. Johnson, R. L. Meagher, Jr., and N. Rozeff Stalkborer damage on yield and quality of sugarcane in Lower Rio Grande Valley of Texas. J. Econ. Entomol. 92: 228Ð234. Leslie, G. W Dispersal behavior of neonate larvae of the Pyralid sugarcane borer Eldana saccharina. Proc. S. Afr. Sug. Technol. Assn. 67: 122Ð126. Martin, F. A., C. A. Richard, and S. D. Hensley Host resistance to Diatraea saccharalis (F.): relationship of sugarcane internode hardness to larval damage. Environ. Entomol. 4: 687Ð688. Martinez, A. J., J. Baird, and T. Holler Mass rearing sugarcane borer and Mexican rice borer for production of parasites Allorhogus pyralophagus and Rhaconotus roslinensis. USDAÐAPHISÐPPQ, APHIS 83Ð1. Mathes, R., and L. J. Charpentier Varietal resistance in sugarcane to stalk moth borers, pp. 175Ð188. In J. R. Williams, J. R. Metcalfe, R. W. Montgomery, and R. Mathes (eds.), Pests of Sugar Cane. Elsevier, New York, NY. Meagher, R. L., Jr., J. W. Smith, Jr., and K.J.R. Johnson Insecticidal management of Eoreuma loftini (Lepidoptera: Pyralidae) on Texas sugarcane: a critical review. J. Econ. Entomol. 87: 1332Ð1344. Meagher, R. L., Jr., L. T. Wilson, and R. S. Pfannenstiel Sampling Eoreuma loftini (Lepidoptera: Pyralidae) on Texas sugarcane. Environ. Entomol. 25: 7Ð16. Metcalfe, J. R The estimation of loss caused by sugarcane moth borers, pp. 61Ð79. In J. R. Williams, J. R. Metcalfe, R. W. Mungomery, and R. Mathes (eds.), Pests of Sugar Cane. Elsevier, Amsterdam, The Netherlands. Posey, F. R., W. H. White, F.P.F. Reay Jones, K. Gravois, M. E. Salassi, B. R. Leonard, and T. E. Reagan Sugarcane borer (Lepidoptera: Crambidae) management threshold assessment on four sugarcane cultivars. J. Econ. Entomol. 99: 966Ð971. Reagan, T. E., and F. R. Posey Development of an insecticide management program that enhances biological control. Proc. Int. Soc. Sugar Cane Technol. 24: 370Ð 373. Reagan, T. E., F. R. Posey, C. Blanco, R. Miller, and J. W. McGee Small plot assessment of insecticides against the Mexican rice borer in sugarcane, Arthro. Manage. Tests 26: 110F. Reay Jones, F.P.F., A. T. Showler, T. E. Reagan, B. L. Legendre, M. O. Way, and E. B. Moser Integrated tactics for managing the Mexican rice borer (Lepidoptera: Crambidae) in sugarcane. Environ. Entomol. 34: 1558Ð1565. Reay Jones, F.P.F., L. T. Wilson, M. O. Way, T. E. Reagan, and C. E. Carlton. 2007a. Movement of Mexican rice borer (Lepidoptera: Crambidae) through the Texas rice belt. J. Econ. Entomol. 100: 54Ð60. Reay Jones, F.P.F., L. T. Wilson, A. T. Showler, T. E. Reagan, and M. O. Way. 2007b. Role of oviposition preference in an invasive crambid impacting two graminaceous host crops. Environ. Entomol. 36: 938Ð951. Reay Jones, F.P.F., L. T. Wilson, T. E. Reagan, B. L. Legendre, and M. O. Way Predicting economic losses from the continued spread of the Mexican rice borer (Lepidoptera: Crambidae). J. Econ. Entomol. 101: 237Ð 250. Ring, D. R., H. W. Browning, K.J.R. Johnson, J. W. Smith, Jr., and C. E. Gates Age speciþc susceptibility of sug-

40 2006 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 105, no. 6 arcane internodes to attack by the Mexican rice borer (Lepidoptera: Pyralidae). J. Econ. Entomol. 84: 1001Ð Salassi, M. E., and M. A. Deliberto Projected Commodity Costs and Returns: Sugarcane Production in Louisiana. A.E.A. Information Series No LSU Ag- Center, Baton Rouge, LA. SAS Institute UserÕs manual, version 9.2. SAS Institute, Cary, NC. Shaver, T. N., H. E. Brown, and D. E. Hendricks Development of pheromone lure for monitoring Þeld populations of Eoreuma loftini (Lepidoptera: Pyralidae). J. Chem. Ecol. 16: 2393Ð2399. Shaver, T. N., H. E. Brown, J. W. Bard, T. C. Holler, and D. E. Hendricks Field evaluations of pheromonebaited traps for monitoring Mexican rice borer (Lepidoptera: Pyralidae). J. Econ. Entomol. 84: 1216Ð1219. Showler, A. T., and B. A. Castro. 2010a. Inßuence of drought stress on Mexican rice borer (Lepidoptera: Crambidae) oviposition preference in sugarcane. Crop Prot. 29: 415Ð 421. Showler, A. T., and B. A. Castro. 2010b. Mexican rice borer, Eoreuma loftini (Lepidoptera: Crambidae), oviposition site selection stimuli on sugarcane, and potential Þeld applications. J. Econ. Entomol. 103: 1180Ð1186. Toth, S. J., Jr., and T. C. Sparks Effect of temperature on toxicity and knockdown activity of cis-permethrin, esfenvalerate, and -cyhalothrin in the cabbage looper (Lepidoptera: Noctuidae). J. Econ. Entomol. 83: 342Ð 346. Tukey, J. W The problem of multiple comparisons. Department of Statistics, Princeton University, Princeton, NJ. USDA ERS World raw sugar price, monthly, quarterly, and by calendar and Þscal year. USDAÐERS. New York Board of Trade, New York. Van Leerdam, M. B Bionomics of Eoreuma loftini a Pyralid stalk borer of sugarcane. Ph.D. dissertation. Texas A&M University, College Station, TX. White, W. H., and S. D. Hensley Techniques to quantify the effect of Diatraea saccharalis (Lepidoptera: Pyralidae) on sugarcane quality. Field Crops Res. 15: 341Ð 348. White, W. H., R. P. Viator, E. O. Dufrene, C. D. Dalley, E. P. Richard, Jr., and T. L. Tew Re-evaluation of sugarcane borer (Lepidoptera: Crambidae) bioeconoics in Louisiana. Crop Prot. 27: 1256Ð1261. Received 12 August 2011; accepted 15 August 2012.

41 Oviposition and larval development of a stem borer, Eoreuma loftini, on rice and non-crop grass hosts J.M. Beuzelin 1 *, L.T. Wilson 2,A.T.Showler 3,A.Meszaros 1,B.E.Wilson 1,M.O.Way 2 & T.E. Reagan 1 1 Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA, 2 Texas A&M AgriLife Research and Extension Center, Texas A&M University, Beaumont, TX 77713, USA, and 3 Kika de la Garza Subtropical Agricultural Research Center, USDA-ARS, Weslaco, TX 78596, USA Accepted: 7 November 2012 DOI: /eea Key words: oviposition preference, larval developmental performance, free amino acids, Lepidoptera, Crambidae, Oryza sativa, Poaceae Abstract A greenhouse study compared oviposition preference and larval development duration of a stem borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), on rice, Oryza sativa L. cv Cocodrie (Poaceae), and four primary non-crop hosts of Texas Gulf Coast rice agroecosystems. Rice and two perennials, johnsongrass, Sorghum halepense (L.) Pers., and vaseygrass, Paspalum urvillei Steud. (both Poaceae), were assessed at three phenological stages. Two spring annuals, brome, Bromus spec., and ryegrass, Lolium spec. (both Poaceae), were assessed at two phenological stages. Phenological stages represented the diversity of plant development stages E. loftini may encounter. Plant fresh biomass, dry biomass, and sum of tiller heights were used as measures of plant availability. Accounting for plant availability, rice was preferred over non-crop hosts, and intermediate and older plants were preferred over young plants. Johnsongrass and vaseygrass were 32 60% as preferred as rice when considering the most preferred phenological stages of each host. Brome and ryegrass received few or no eggs, respectively. Eoreuma loftini larval development (in degree days above developmental threshold temperatures) was fastest on rice and slowest on johnsongrass and vaseygrass. Development duration was only retarded by plant stage on young rice plants. Foliar and stem free amino acid concentrations were determined to help provide insights on the mechanisms of E. loftini oviposition preference and developmental performance. Introduction Eoreuma loftini (Dyar) (Lepidoptera: Crambidae) is a stem borer indigenous to Mexico that has become an invasive pest of grass crops in the Gulf Coast regions of Texas and Louisiana (Hummel et al., 2010). In addition to sugarcane, Saccharum spp., and rice, Oryza sativa L., E. loftini infests a wide range of non-crop graminoids (Van Zwaluwenburg, 1926; Beuzelin et al., 2011a,b; Showler et al., 2011). Periodic sampling over 2 years showed that non-crop grasses in southeast Texas rice production areas host E. loftini at densities between 0.2 and 5.7 immatures per m 2 (Beuzelin et al., 2011a). Primary hosts were the perennials johnsongrass, Sorghum halepense (L.) Pers., and *Correspondence and current address: Julien Beuzelin, Dean Lee Research Station, 8105 Tom Bowman Dr., Alexandria, LA 71302, USA. jbeuzelin@agcenter.lsu.edu vaseygrass, Paspalum urvillei Steud., as well as the annuals ryegrass, Lolium spp., and brome, Bromus spp. (all Poaceae) (Beuzelin et al., 2011a). Because non-crop grasses increase host availability in the ecosystem, they play a role in E. loftini population dynamics and may contribute to economically damaging populations in host crops. However, the extent to which non-crop hosts increase E. loftini populations remains poorly understood. Host-specific development, survival, fecundity, and preference are key factors influencing the relative contribution of multiple host plants to herbivore populations. Meagher et al. (1996) observed variations in E. loftini immature development time and pupal weight among sugarcane genotypes, but differences in oviposition were not detected. Reay-Jones et al. (2003, 2005) did not find differences in E. loftini larval survival among sugarcane cultivars grown in Louisiana and Texas. Subsequent studies involving sugarcane showed that cultivar HoCP is 17 37% less preferred for oviposition than LCP The Netherlands Entomological Society Entomologia Experimentalis et Applicata 146: , Entomologia Experimentalis et Applicata 2013 The Netherlands Entomological Society

42 Oviposition and larval development of Eoreuma loftini 333 based on numbers of egg clusters and eggs per plant, and eggs per egg cluster (Reay-Jones et al., 2007a). Reay-Jones et al. (2007a) and Showler & Castro (2010a) showed that E. loftini also prefers drought-stressed sugarcane for oviposition. Increased preference was associated with a greater abundance of oviposition substrate (folded dry leaf material) and increased levels of free amino acids (FAAs). Showler et al. (2011) studied oviposition and injury on five weedy grasses, including johnsongrass and vaseygrass. Johnsongrass received more E. loftini eggs than vaseygrass on a per plant basis. Johnsongrass also exhibited more adult exit holes than vaseygrass, indicating differences in E. loftini immature performance (Showler et al., 2011). Previous studies show that E. loftini oviposition preference and immature performance are affected by host plant species and genotype, stress, and phenology (Meagher et al., 1996; Reay-Jones et al., 2007a; Showler et al., 2011). To better understand the role of non-crop hosts in rice agroecosystems of the Gulf Coast, a study was conducted to determine E. loftini oviposition preference and larval development duration on rice and four primary non-crop hosts. Materials and methods Greenhouse experiment A greenhouse experiment was conducted at the Texas A&M AgriLife Research and Extension Center at Beaumont (Beaumont, TX, USA; N, W) during the summer of Rice (cv. Cocodrie), johnsongrass and vaseygrass (perennial grasses), and brome and ryegrass (annual grasses) were studied. Rice and johnsongrass seeds were obtained from the Louisiana State University Agricultural Center Rice Research Station (Rayne, LA, USA) and Azlin Seed Service (Leland, MS, USA), respectively. Other seeds were obtained from on-farm collections in Chambers and Jefferson Counties, TX, USA, during 2007 (brome, ryegrass) and 2008 (vaseygrass). Thirteen plant 9 stage combinations, hereafter referred to as host treatments, were studied. Rice and the perennials were evaluated at three phenological stages. The annuals were evaluated at two phenological stages. Phenological stages were selected to represent the diversity of plant development stages encountered by E. loftini in Gulf Coast rice agroecosystems. At the time of E. loftini oviposition assessment, young rice was between the late tillering and panicle differentiation stages, and the young non-crop grasses were in vegetative growth (Table 1). Intermediate rice was early in the panicle exertion stage, while the oldest tillers of intermediate johnsongrass and vaseygrass exhibited emerging inflorescences and mature seed heads, respectively. Intermediate brome and ryegrass were in a vegetative stage (Table 1). Older rice plants exhibited maturing panicles in the hard dough stage, whereas older johnsongrass and vaseygrass had mature seed heads. Plantings were scheduled to produce the various phenological stages simultaneously, with the earliest planting initiated on 14 April 2009 for vaseygrass. Planting occurred in 3.8-l pots filled with sterilized soil provided by the Louisiana State University Central Research Station greenhouse services (2:1:1 soil:sand:peat moss mixture). For each host treatment, pots were used. Final plant density was reduced to one plant per pot, with the exception of two young annual grasses per pot. For rice, three seeds were planted directly in each pot, and 2 3 weeks after seedling emergence, all but one plant were removed. For non-crop grasses, seeds were soaked in a gibberellic acid solution (300 p.p.m., N-Large; Stoller Enterprises, Houston, TX, USA) for h at 20 C, and then planted in cmplasticflats.On7 14 days after emergence, four seedlings were transplanted into each pot. Three weeks after transplant, all but one plant were removed. Plants were fertilized 7 14 days after seedling emergence (rice) or at transplanting (non-crop grasses) with 300 mg of urea and 250 ml of Miracle-Gro Water Soluble All Purpose Plant Food ( N-P-K; Scotts Company, Marysville, OH, USA) solution at 3.7 g l 1 per pot. The first plantings of rice, johnsongrass, and vaseygrass were fertilized a second time on 16 June with 300 mg of urea and 80 ml of Miracle-Gro solution per pot. On 21 July, the first and second plantings of rice, johnsongrass, and vaseygrass, as well as the first plantings of brome and ryegrass, were fertilized with 300 mg of urea and 80 ml of Miracle-Gro solution per pot. Plants were provided with 0.5 l of water per pot every other day. Thirteen m cages were constructed from PVC pipes (2.13 cm outside diameter) and covered with white polyester, 0.25-mm mesh netting. Cages were arranged in two adjacent rows of six and seven cages each, perpendicular to the cooling panel of the greenhouse. Temperatures were recorded every 15 min using two HOBO U10 data loggers (Onset Computer Corporation, Pocasset, MA, USA). The cages closest and farthest from the greenhouse cooling panel each had one data logger located 1.2 m above the floor. Temperatures in each of the 13 cages were estimated using equation (1): T i ¼ 6 i T 0 þ i 6 6 T 6; ð1þ where T i = the temperature in a cage at the i-th position, with i {0,1,2,3,4,5,6} and i = 0 for the cages closest to the cooling panel (two cages per position at positions 0 5,

43 334 Beuzelin et al. one cage at position 6), T 0 = the temperature recorded in the cage closest to the cooling panel, and T 6 = the temperature recorded in the cage farthest from the cooling panel. One pot of each host treatment was placed into each cage at a random location 1 week before oviposition was assessed. Insects used in the experiments were obtained from a colony maintained at the USDA-ARS Kika de la Garza Subtropical Agricultural Research Center in Weslaco, TX, USA ( N, W). The E. loftini colony was established from larvae collected in commercial sugarcane fields near Weslaco, during the spring of Insects were reared on artificial diet (Martinez et al., 1988) at 25 C, 65% r.h., and L14:D10 photoperiod. Pupae were separated by sex, and shipped overnight to the Texas A&M AgriLife Research and Extension Center at Beaumont. Pupae were kept in the greenhouse, and upon adult eclosion (<24 h), 10 females and 5 10 males were confined together in 473-ml paper containers (Neptune Paper Products, Newark, NJ, USA) for 24 h to allow for mating. Adults were released between 17:00 and 19:00 hours from one paper container placed at the center of each cage. Eoreuma loftini releases occurred between 14 and 26 August. After allowing for three full nights of egg laying, each plant was visually inspected for eggs. The number of oviposition events (i.e., egg clusters and single eggs laid 5mmfrom one another) and eggs per oviposition event were determined using a magnifying lens. With the exception of two cages where a small proportion of the eggs were recovered on the mesh cloth, E. loftini oviposition exclusively occurred on plant material. Eggs laid on the mesh cloth were destroyed and not included in data analyses. After oviposition data collection, plants were maintained in cages for 5 6 weeks and then dissected for collection of E. loftini larvae and pupae (18 September 4 October). Recovered pupae were kept in the greenhouse in 30-ml plastic cups until adult eclosion. Recovered larvae were reared on artificial diet (Martinez et al., 1988) in plastic cups maintained in the greenhouse until pupation and adult eclosion. Adult eclosion was recorded daily until the experiment was ended on 24 November. Plant measurements The numbers of tillers, numbers of green and dry leaves, and tiller heights from the soil surface to the tip of the tallest leaf were recorded for each plant in each cage immediately prior to moth release. From five representative plants not used for oviposition assessment, numbers of tillers, tiller heights, and plant fresh biomasses were recorded for each host treatment. Dry biomass was recorded after 5daysinanovenat75 C. For each host treatment, simple linear regressions (Proc REG; SAS Institute, 2008) were conducted using the sum of tiller heights by plant as the explanatory variable, and plant fresh and dry biomasses as response variables. Parameters from these regressions were used to estimate biomasses for each plant in each cage. During plant dissection, numbers of tillers, tiller heights, and tiller diameters (as measured ca. 1 cm below the first visible node, or ca. 3 cm above the cut if the nodal position was not determined) were recorded for each plant in each cage. One-way ANOVAs were used to compare plant characteristics as affected by host treatment and least squares means (LS means) were separated using the Tukey adjustment (a = 0.05) (Proc MIXED; SAS Institute, 2008). Cage was included in the ANOVA models as a random effect. In addition, multiple contrasts compared selected groups of host treatments (Proc MIXED) with P-values adjusted using the step-down Bonferroni method to control familywise error rates (Proc MULTTEST; SAS Institute, 2008). Free amino acid analyses Concurrently to oviposition assessment, samples of each host treatment collected from five (rice, johnsongrass, vaseygrass) or four (brome, ryegrass) plants not used for oviposition were used for FAA analyses. Whole-plant samples, excluding roots, were collected from young annual grasses. Leaf and stem samples were collected from other plants. For leaves, a composite sample of the midsection of at least two green leaf blades was collected from each plant. For stems, a composite sample of the midsection of one or more culms (stems with leaf sheaths removed) was collected from each plant. Samples were stored on dry ice upon collection, before being placed in a 80 C freezer. Each sample (0.5 1 g fresh biomass) was ground in a mortar with liquid N and subsequently homogenized with 0.1 N HCl (1 ml per 0.1 g of sample) using a Virtishear homogenizer (Virtis, Gardiner, NY, USA) for s. After allowing homogenized samples to settle for 1 2 min, the clear fraction between the floating and precipitating debris was pipetted into 1.5-ml Eppendorf tubes and stored at 80 C. Each sample was processed using the method of Showler & Castro (2010a) with an Agilent 1100 Series HPLC system (Agilent Technologies, Atlanta, GA, USA). Concentrations of nine derivatized essential FAAs and eight non-essential FAAs were determined. Essential FAAs are not synthesized by insects and their absence in food sources can prevent development (Chapman, 1998). Essential FAAs include arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, and valine. The 10th essential FAA, tryptophan, was not detected using our instrumentation. Non-essential FAAs include alanine, aspartate, cystine, glutamate, glycine, proline, serine, and tyrosine. ANOVAs (Proc MIXED) were

44 Oviposition and larval development of Eoreuma loftini 335 used to compare concentrations of each FAA, in pmol of FAA per ll of juice, in leaves and stems as affected by host treatment. Fixed effects for the ANOVA models were host treatment and host tissue (host treatment). The effect of individual plants i.e., plant(host treatment) was included as a random effect. Least squares means were separated using the Tukey-Kramer adjustment (a = 0.05). In addition, a principal component analysis on standardized averages of FAA concentrations in leaves and stems for each host treatment was performed to assist in visualizing potential associations between combinations of FAAs and host treatments (Proc PRINCOMP; SAS Institute, 2008). Oviposition preference estimation Oviposition preference is a departure from random plant host selection when multiple plant hosts are simultaneously available for egg laying. A preference coefficient (Wilson & Gutierrez, 1980; Murphy et al., 1991; Reay- Jones et al., 2007a) for a host plant, which accounts for plant availability, can be estimated using equation (2): ^a i ¼ n i=a i maxðn=aþ ð2þ where ^a i = the estimated preference coefficient for the i-th host, n i = the number of eggs laid on the i-th host, A i = the availability of the i-th host (fresh biomass in g, dry biomass in g, sum of tiller heights in cm of tiller), and max(n/a) = the maximum number of eggs laid per unit of a host, adjusted for relative plant availability, across the different hosts. Oviposition on each available host plant can in turn be determined using equation (3): ^a i A i ^n i ¼ n total ð3þ PI ^a i A i Where ^n i = the estimated relative oviposition selection in number of eggs or oviposition events for the i-th host, n total = the total number of eggs or oviposition events laid across all hosts, ^a i = the estimated preference coefficient for the i-th host, and A i = the availability of the i-th host. Relative oviposition preference coefficients as affected by host treatment were estimated with least squares nonlinear regressions (JMP; SAS Institute, 2002) using equation (3). Coefficients with overlapping 95% confidence intervals [parameter estimate SE 9 t (a/2, d.f. error) with t (a/2, d.f. error) = 1.975] were not considered different. In addition, the number of eggs per oviposition event was compared among host treatments using a one-way ANOVA (Proc MIXED). The ANOVA model included cage and cage*host treatment as random effects. The total number i¼1 of plants receiving eggs for each host treatment (replicates) varied (n = 2 13). Pearson correlations among preference coefficients and LS means of selected plant characteristics were determined using Proc CORR (SAS Institute, 2008). Larval development duration estimation Using estimates from van Leerdam (1986), larval development duration in degree days (ºD>T 0 ) was estimated for each larva or pupa recovered from a plant dissection that produced an adult. Van Leerdam (1986) studied E. loftini immature development durations at temperatures between 20 and 32 C on both artificial diet and sugarcane stalk sections. Results derived from van Leerdam (1986) suggest that egg and pupal development durations in ºD>T 0 are approximately constant regardless of food source (87.5 ºD>13.6 C for eggs, and ºD>14.0 C and ºD>13.8 C formale and female pupae, respectively). Duration to complete larval development on artificial diet is ºD>14.9 C and ºD>14.6 C for males and females, respectively (van Leerdam, 1986). For each recovered immature, the time of larval eclosion was estimated by summing ºD from the day subsequent to moth release at 12:00 hours until the duration of the egg stage was attained. Time of pupation was estimated by summing ºD from the day of adult eclosion at 12:00 hours backwards until the pupal stage was attained. When pupae were recovered during plant dissection, larval development occurred exclusively on the plant, and ºD between larval eclosion and pupation were computed directly. When larvae were recovered, development occurred on the plant and subsequently on diet. Thus, total larval development duration on the plant was estimated using equation (4): ^Dtotal ij ¼ 1 P dis ecl D P ij pup D dis ij Dtotal diet ð4þ where ^Dtotal ij = the estimated total larval development duration on the i-th host for the j-th larva, P dis ecl D ij = the sum of ºD from larval eclosion to plant dissection on the i-th host for the j-th larva, P pup dis D ij = the sum of ºD on artificial diet from plant dissection to pupation for the j-th larva recovered from the i th host, and Dtotal diet = the total larval development duration on artificial diet (van Leerdam, 1986). This approach assumed that larval development on artificial diet after plant dissection was not affected by prior feeding on the host plant. Because substantial interplant movement of neonates occurred within each cage under our experimental conditions, all host treatments were infested with E. loftini, and the duration

45 336 Beuzelin et al. of larval development could be estimated for males and females on all host treatments. Larval development durations were compared using a two-way ANOVA with host treatment and sex as factors (Proc MIXED). Larvae for which relative development on plant prior to dissection 1 P pup dis D ij =Dtotal diet was less than 0.15 were eliminated from the analysis because their development was considered abnormally slow (a relative larval development of 0.15 corresponds to late first or early second instars; van Leerdam, 1986). The total number of plants with at least one recovered immature for each host treatment (replicates for host treatment) varied (n = 6 13). ANOVA random effects included cage and cage* host treatment. When fixed effects were detected (P<0.05), the Tukey-Kramer adjustment (a = 0.05) was used to separate LS means. In addition, multiple contrasts compared selected groups of host treatments (Proc MIXED) with P-values adjusted using the step-down Bonferroni method (Proc MULTTEST). Pearson correlations between LS means of development durations and preference coefficients, and LS means of selected plant characteristics, were determined using Proc CORR. Results Plant physical characteristics and free amino acid concentrations The host treatments presented a wide range of biomass, tiller, and leaf availability to moths and larvae (Tables 1 and 2). On 5 6 weeks after oviposition, brome and ryegrass were still in vegetative development but showed broken, desiccated injured tillers because of larval feeding. For young rice, non-injured tillers were between milk and hard dough stages, whereas injured tillers exhibited dead panicles in the boot or panicle exertion stages. Intermediate and older rice exhibited non-injured tillers with mature panicles and senescent foliage; however, tillers sustaining E. loftini boring injury during panicle exertion displayed whiteheads (blank panicles with dead grain). For perennial grasses, young johnsongrass and vaseygrass exhibited maturing and mature seed heads, respectively. Intermediate and older johnsongrass showed young vegetative tillers growing from rhizomes in addition to flowering and mature tillers with dispersed seeds. Intermediate and older vaseygrass displayed a mixture of vegetative, flowering, mature, and senescing tillers. Concentrations of FAAs, whether in leaves or stems, were variable and numerous differences between host treatments, phenological stages, and leaf vs. stem tissues were found (Table 3). Threonine, glutamate, and alanine were detected in leaves and stems of all host treatments, whereas methionine was only detected in leaves of older johnsongrass. Cystine was only detected in leaves of intermediate and older johnsongrass. For more than 70% of sampled plants, when threonine, glutamate, alanine, and glycine were detected in leaves, they were also detected in stems. In rice, glutamate and serine represented 17 42% and 36 37%, respectively, of all FAAs detected in leaves and stems (Table 3). In rice stems, aspartate was also abundant, representing 28 38% of detected FAAs. In vaseygrass, alanine represented 20 89% of all FAAs detected in leaves and stems. Proline represented more than 20% of FAAs in brome, intermediate ryegrass, and intermediate johnsongrass (Table 3). The first and second principal components accounted for 27.0 and 24.3%, respectively, of the variance in the FAA concentration dataset (data not shown). The biplot summarizing the relative positions of host treatments and FAA concentrations in leaves and stems over the first two principal components did not provide additional information (data not shown). Eoreuma loftini oviposition A total of E. loftini eggs were observed during this study, 99.5% of which were laid in clusters (283 clusters observed). Thirty-one eggs laid singly were also observed. Hereafter, the deposition of eggs, whether singly or in clusters, is referred to as an oviposition event. Of the oviposition events, 96.5% occurred in and 99.2% of the eggs were laid in folds of dry plant material, leaf, or leaf sheath. The mean ( SE) number of eggs per oviposition event was and showed limited differences (F 8,46 = 2.00, P = 0.068) among host treatments (Figure 1). Preference coefficients for the number of eggs and oviposition events per g plant fresh biomass, per g plant dry biomass, and per cm of tiller accounted for about 60% of variability in the observed oviposition data (P<0.05; Figure 2). Rice was more preferred than non-crop grasses with young, intermediate, or older rice having preference coefficients equal to 1 regardless of preference estimation method (Figure 2). Young brome, young johnsongrass, and young and intermediate ryegrass had preference coefficients equal to zero because oviposition did not occur on these hosts (Figure 2). Based on the number of eggs per g of plant fresh biomass, older rice was the most preferred host (Figure 2), followed by intermediate rice (76% as preferred), and intermediate and older perennials (24 37% as preferred). Preference for intermediate brome was lower than that for older rice (6% as preferred), but was not different from that for other hosts. The variability of preference for young rice and vaseygrass was high as shown by large standard errors (Figure 2). Thus, although preferences were low for these young hosts, differences with preferences for

46 Oviposition and larval development of Eoreuma loftini 337 Table 1 Rice and non-crop grass plant characteristics (LS means) recorded during Eoreuma loftini oviposition preference and larval development assessment in a greenhouse experiment, Beaumont, TX, USA, 2009 Oviposition assessment Development assessment Host treatment 1 Age 2 (weeks) Fresh weight 3 (g) Dry weight 3 (g) No. tillers Sum of tiller heights (cm) No. leaves No. dry leaves 4 Ratio of dry leaves to green leaves No. tillers Sum of tiller heights (cm) Tiller stem diameter (mm) Rice Young 5 8.8fg 1.6cd 4.6ef 243.2e 20.8fg 2.2e 0.12ef 5.5de 317.3e 3.7b Intermediate c 17.4b 8.5bcd 604.9bcd 50.5cd 12.8cd 0.34cd 10.4cd 656.7cd 3.7b Older d 17.0b 6.8de 468.3d 47.4cd 23.7a 1.04a 8.2de 523.9cde 4.0b Johnsongrass Young e 3.1cd 2.0f 148.5ef 12.1g 0.3e 0.03f 2.2e 265.4e 5.1a Intermediate c 20.2b 4.3ef 565.3cd 38.1def 10.8cd 0.41c 6.0de 728.9c 4.1b Older b 29.0a 5.2def 648.3bc 47.5cd 22.5a 0.95a 5.8de 704.1c 3.8b Vaseygrass Young e 3.5c 6.8de 271.3e 26.3efg 3.7e 0.18def 8.2de 426.9de 3.0c Intermediate a 26.8a 12.2b a 69.8b 16.2bc 0.30cde 19.4b a 3.6bc Older c 18.2b 11.5bc 903.0a 61.7bc 25.7a 0.74b 15.6bc b 3.7b Brome Young 6 0.8g 0.2d 2.5f 59.0f 10.8g 1.2e 0.13ef 9.5cd 297.9e 2.1de Intermediate ef 4.1c 7.2de 270.2e 40.6de 10.2d 0.33cd 10.3cd 312.2e 2.3d Ryegrass Young 6 1.3g 0.2d 8.1cde 134.0ef 26.0efg 0.8e 0.04f 33.8a b 1.5f Intermediate fg 1.4cd 24.5a 726.2b 104.8a 20.0ab 0.24cde 27.1a b 1.6ef F 12,144 (all P<0.001) Least squares means within a column with the same letter are not different (Tukey or Tukey-Kramer adjustment: a = 0.05). 1 Least squares means reported on a per plant basis, except for young annual grasses (two plants). 2 Plant age post-emergence. Larval development assessment was subsequent to plant dissection 5 6 weeks after oviposition assessment. 3 Estimated from five separate representative plants. 4 one-third leaf was dry.

47 338 Beuzelin et al. Table 2 Contrasts comparing plant characteristics recorded during Eoreuma loftini oviposition preference and larval development assessment in a greenhouse experiment, Beaumont, TX, USA, 2009 Oviposition assessment Development assessment Comparison (d.f. = 1.144) Fresh weight Dry weight No. tillers Sum of tiller heights No. leaves No. dry leaves Ratio of dry leaves to green leaves No. tillers Sum of tiller heights Tiller stem diameter Non-crop grasses vs. rice * 11.99* * 36.67* 51.47* 72.54* Perennials vs. rice * 99.56* * * 0.97 Annuals vs. rice * * 42.00* 33.82* * 93.62* * 24.17* * Perennials vs. annuals * * 47.54* * * 82.64* * 6.24* * Brome vs. rice * * 5.92* 88.97* 16.74* 43.08* 48.38* * * Johnsongrass vs. rice * 95.81* 18.13* * * Ryegrass vs. rice * * * * * * * * Vaseygrass vs. rice * 56.16* 30.03* 133.6* 18.77* * 29.22* * 11.63* Johnsongrass vs. vaseygrass 12.57* 5.26* 94.84* * 44.13* 16.50* * * 72.68* Johnsongrass vs. brome * * * * 36.19* 15.84* 24.69* * Johnsongrass vs. ryegrass * * * * * * * * Vaseygrass vs. brome * * 53.80* * 63.47* 75.63* 20.80* 11.55* * * Vaseygrass vs. ryegrass * * 70.15* * 14.32* 19.45* 46.79* * * Brome vs. ryegrass * * 69.51* * 15.32* * * 29.23* *P<0.05 using the step-down Bonferroni adjustment for multiple contrasts.

48 Oviposition and larval development of Eoreuma loftini 339 Table 3 Free amino acid concentrations (pmol of FAA per ll of juice) in rice and non-crop grasses (LS means) in a greenhouse experiment, Beaumont, TX, USA, 2009 Essential FAAs Non-essential FAAs Host treatment Tissue Arginine Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Valine Alanine Aspartate Cystine Glutamate Glycine Proline Serine Tyrosine (a) Individual FAAs Rice Young Stems 8 0d 0d 0b 0c 0 0d 32 e 27bcd 4d 589bcd 0b 521cd 37c 0ef 317b 0c Leaves cd 35bcd 90ab 18bc 0 21bcd 93e 138bcd 10d 170def 0b 868ab 128bc 0ef 346b 0c Intermediate Stems 10 38d 86abcd 86ab 0c 0 0d 39e 219b 4d 826bc 0b 712bc 30c 0ef 254b 0c Leaves cd 0d 23b 0c 0 28bcd 55e 74bcd 6d 21ef 0b 315def 143bc 0ef 234b 0c Older Stems 49 20d 158a 106ab 98abc 0 0d 161cde 434a 11d 1833a 0b 1124a 155bc 0f 2386a 0c Leaves 16 73cd 0d 0b 0c 0 0d 70e 66bcd 7d 260def 0b 480cde 630a 94cde 770b 0c Johnsongrass Young Stems 0 0d 0d 0b 0c 0 0d 2e 0d 1d 9ef 0b 29f 0c 0ef 7b 0c Leaves 0 34d 0d 0b 0c 0 0d 2e 22cd 1d 0f 0b 9f 13c 0ef 3b 0c Intermediate Stems 0 0d 0d 0b 0c 0 0d 3e 0d 1d 7ef 0b 14f 0c 87def 2b 0c Leaves 0 20d 18cd 0b 0c 0 0d 18e 14cd 1d 0f 39b 9f 10c 164bcd 7b 0c Older Stems 11 18d 23cd 0b 39abc 0 102ab 42e 111bcd 2d 133def 0b 47f 38c 0ef 41b 28c Leaves 17 35d 40bcd 0b 0c abcd 22e 117bcd 2d 16ef 604a 15f 86c 0ef 34b 0c Vaseygrass Young Stems d 0d 0b 0c 0 0d 92e 0d 3296bcd 13ef 0b 142ef 16c 0ef 59b 369bc Leaves a 0d 0b 0c 0 0d 443b 0d 11222a 0f 0b 105f 82c 0ef 153b 178c Intermediate Stems cd 12cd 0b 11bc 0 26bcd 344b 92bcd 2005bcd 543cde 0b 580bcd 123bc 0ef 366b 964a Leaves cd 0d 0b 0c 0 0d 277bcd 0d 5208bc 12f 0b 76f 119bc 0ef 15b 0c Older Stems ab 15cd 0b 0c 0 91abc 651a 195bc 1477cd 1098b 0b 316def 408ab 0ef 2066a 720ab Leaves bc 0d 0b 0c 0 0d 302bc 0d 6323ab 23ef 0b 94f 223bc 0ef 102b 59c Brome Young Leaves 92 18d 151ab 123ab 118abc 0 160a 98de 79bcd 19cd 53def 0b 361cdef 240bc 485a 62b 32c Intermediate Stems 88 21d 68abcd 0b 118abc 0 71abcd 42e 46bcd 5cd 20def 0b 115f 28c 250b 23b 0c Leaves 67 0d 0d 0b 32abc 0 64abcd 38e 32bcd 4d 5ef 0b 97f 40c 230bc 19b 0c Ryegrass Young Leaves 121 9d 129abc 209a 171a 0 63abcd 90de 81bcd 17cd 87def 0b 514bcd 124bc 245b 50b 16c Intermediate Stems 26 5d 0d 0b 134ab 0 0cd 10e 29bcd 3d 14ef 0b 75f 21c 226bc 0b 0c Leaves 0 18d 0d 0b 66abc 0 10bcd 20e 36bcd 4cd 5ef 0b 84f 28c 256b 26b 0c Host treatment F 11, P>F <0.001 <0.001 <0.001 < <0.001 <0.001 <0.001 <0.001 < <0.001 <0.001 <0.001 <0.001 <0.001 Tissue (host treatment) F11,42 P>F <0.001 < <0.001 <0.001 <0.001 < <0.001 <0.001 <0.001 <0.001 <0.001

49 340 Beuzelin et al. Table 3 Continued Host treatment Tissue Total FAAs Essential FAAs Non-essential FAAs (b) Grouped FAAs Rice Young Stems efg 66.8b cde Leaves efg 533.2ab cde Intermediate Stems defg 477.7ab bcde Leaves fg 335.9ab 719.8de Older Stems bcde ab bcd Leaves cdefg 225.4ab bcde Johnsongrass Young Stems 47.8g 2.0b 45.8e Leaves 84.5g 58.0b 26.5e Intermediate Stems 113.0g 2.7b 110.3e Leaves 299.6fg 70.0b 229.6e Older Stems 636.5fg 347.6ab 288.9e Leaves fg 467.1ab 757.3de Vaseygrass Young Stems bcdefg 247.1ab bcde Leaves a 928.1ab a Intermediate Stems bcdef 861.8ab bcde Leaves abc a bcd Older Stems bcd ab bc Leaves ab ab ab Brome Young Leaves cdefg 839.3ab cde Intermediate Stems 894.0fg 453.1ab 440.9de Leaves 628.4fg 234.1ab 394.4de Ryegrass Young Leaves efg 872.8ab cde Intermediate Stems 544.0fg 204.9ab 339.1de Leaves 553.6fg 150.0ab 403.6de Host treatment F 11, P>F < <0.001 Tissue (host treatment) F11, P>F < <0.001 Least squares means within a column with the same letter are not different (Tukey-Kramer adjustment: a = 0.05).

50 Oviposition and larval development of Eoreuma loftini 341 Figure 1 Number of Eoreuma loftini eggs per oviposition event (LS means + SE) on rice and four non-crop hosts. ANOVA did not detect differences among host treatments (P>0.05). intermediate and older hosts were not always detected. Based on the number of eggs per g of plant dry biomass, young rice was the most preferred host (Figure 2). Intermediate brome, intermediate and older vaseygrass, and intermediate and older johnsongrass were 7 32% as preferred. Based on the number of eggs per cm of tiller, older rice was the most preferred host (Figure 2). The pattern for preference based on the number of eggs per cm of tiller was comparable to that of preference based on the number of eggs per g of plant fresh biomass. However, when the sum of tiller heights was used as a measure of plant availability, differences were greater between preferences for young and intermediate rice (0.55 vs. 0.22), and between preferences for young and older rice (0.79 vs. 0.46). Based on the number of oviposition events per g of plant fresh biomass and per cm of tiller, intermediate rice was the most preferred host (Figure 2). Preferences based on fresh biomass and cm of tiller were less for the most preferred stage of johnsongrass (51 and 40%, respectively) and vaseygrass (53 and 52%, respectively). Based on the number of oviposition events per g of plant dry biomass, young rice was the most preferred host (Figure 2). Correlations among preference coefficients predicting numbers A B Figure 2 Oviposition preference coefficients (+ SE) predicting the number of Eoreuma loftini (A) eggs and (B) oviposition events, based on from left to right fresh weight, dry weight, or sum of tiller heights as measures of plant availability. Coefficients estimated using nonlinear least-squares regressions range from 0 (no oviposition) to 1 (maximum preference, marked with *). Bars capped with the same letter are not different using overlap of 95% confidence intervals.

51 342 Beuzelin et al. of eggs (r = , P<0.05) and among those predicting numbers of oviposition events (r = , P<0.05) were detected. In addition, correlations between preference coefficients predicting numbers of eggs and those predicting numbers of oviposition events were detected (r = , P<0.05). Preference coefficients were not correlated with the number of dry leaves per plant and stem diameter (P>0.05; Table 4). However, preference coefficients predicting numbers of eggs and oviposition events based on fresh biomass and sum of tiller heights were positively correlated with the ratio of dry to green leaves (P<0.05; Table 4). Preference coefficients based on dry biomass were not associated with the ratio of dry to green leaves (P>0.05; Table 4). Preference coefficients were not correlated with total, essential, and non-essential FAA concentrations (P>0.05; Table 5). When considering individual FAAs, preference coefficients were positively correlated with concentrations of serine in leaves, and of aspartate, glutamate, and valine in stems (r = , P<0.05). Concentrations of proline in stems were negatively correlated with preference coefficients (r = to 0.620, P<0.05). Larval development duration Eoreuma loftini larval development duration changed with host treatment (F 12,90 = 10.45, P<0.001; Figure 3) but differences between male and female larvae were not detected (F 1,410 = 1.02, P = 0.31). In addition, the host treatment*sex interaction was not significant (F 12,410 = 0.55, P = 0.88). Development duration on johnsongrass was not different from that on vaseygrass, and on brome it was not different from that on ryegrass (Table 6). Larval development was 1.4-fold longer on non-crop grasses than on rice (Figure 3). However, while development was 1.7-fold longer on the perennials than on rice, differences in development durations between annuals and rice were not detected (P>0.05; Table 6). Development durations were not affected by plant stage, except for larvae that developed 1.5-fold slower on young rice than on intermediate and older rice (Figure 3). Correlations between larval development durations and oviposition preference coefficients were not detected (0.29<P<0.61). Larval development duration was not correlated with plant availability estimates (P>0.05), excluding a positive association with stem diameter (P<0.05; Table 4). Development durations were not correlated with total, essential, and non-essential FAA concentrations (P>0.05; Table 5). When considering individual FAAs, larval development durations were negatively correlated with concentrations of glutamate, isoleucine, leucine, and lysine in stems (r = to 0.750, P<0.05). Discussion Eoreuma loftini oviposition preference is greater for rice than for four primary non-crop hosts occurring in Gulf Coast rice agroecosystems, based on plant fresh biomass, dry biomass, and sum of tiller heights. Reay-Jones et al. (2007a) found rice more attractive for oviposition than sugarcane based on plant dry biomass. Among non-crop hosts, Showler et al. (2011) reported that E. loftini oviposited a greater proportion of eggs on johnsongrass than on vaseygrass. In our study, however, E. loftini showed comparable oviposition preferences for these two perennial grasses. Our data also suggest that under choice conditions, E. loftini moths will lay a limited number of eggs on brome and ryegrass. Eoreuma loftini eggs were laid almost exclusively in folds on dry plant material regardless of plant host, confirming Table 4 Pearson correlations (n = 13) of oviposition preference coefficients with Eoreuma loftini larval development durations and selected plant physical characteristics Larval development duration No. dry leaves Ratio of dry leaves to green leaves Tiller stem diameter r P r P r P r P Preference coefficient Eggs per g fresh weight Eggs per g dry weight Eggs per cm of tiller Oviposition events per g fresh weight Oviposition events per g dry weight Oviposition events per cm of tiller Larval development duration

52 Oviposition and larval development of Eoreuma loftini 343 Table 5 Pearson correlations (n = 13) of Eoreuma loftini oviposition preference coefficients and larval development durations with plant FAA concentrations Total FAAs Essential FAAs Non-essential FAAs in leaves in stems in leaves in stems in leaves in stems r P r P r P r P r P r P Preference coefficient Eggs per g fresh weight Eggs per g dry weight Eggs per cm of tiller Oviposition events per g fresh weight Oviposition events per g dry weight Oviposition events per cm of tiller Larval development duration Table 6 Contrasts comparing Eoreuma loftini larval development durations on rice and four non-crop hosts in a greenhouse experiment, Beaumont, TX, USA, 2009 Comparison (d.f. = 1,90) Larval development duration Non-crop grasses vs. rice 40.48* Perennials vs. rice 63.70* Annuals vs. rice 0.61 Perennials vs. annuals 38.35* Brome vs. rice 0.31 Johnsongrass vs. rice 68.05* Ryegrass vs. rice 0.40 Vaseygrass vs. rice 20.58* Johnsongrass vs. vaseygrass 2.38 Johnsongrass vs. brome 36.22* Johnsongrass vs. ryegrass 28.52* Vaseygrass vs. brome 12.28* Vaseygrass vs. ryegrass 10.04* Brome vs. ryegrass 0.02 *P<0.05 using the step-down Bonferroni adjustment for multiple contrasts. that E. loftini oviposition preference is associated with the availability of folds in dry leaf material (Showler & Castro, 2010b). This behavior may explain why young plants are not preferred. In addition, variations in oviposition have been associated with characteristics of live plant material (Reay-Jones et al., 2007a; Showler & Castro, 2010a,b). Reay-Jones et al. (2007a) and Showler & Castro (2010a) found that differences in foliar FAA concentrations might have a role in E. loftini preference between genotypes of Figure 3 Eoreuma loftini larval development durations (LS means + SE) in degree days (ºD>T 0 ). Bars with the same letter are not different (Tukey-Kramer adjustment: P<0.05). the same host plant species, and between plants of the same genotype under different levels of stress. The lack of association between E. loftini oviposition preference and detectable FAA concentrations among host plant species in our study suggests that FAA concentrations might not have an influential role in determining preference among species or phenological stages within species (Showler & Reagan, 2012). Some herbivores, such as Spodoptera exigua (H ubner), prefer hosts with greater amounts of essential FAAs (Showler, 2001, 2012). Eoreuma loftini oviposition preference, however, is likely to be affected more by other morphological and biochemical factors than by amounts of FAAs (AT Showler, unpubl.). These factors include relative amounts of certain sugars (AT Showler, unpubl. data). Additional factors potentially affecting E. loftini oviposi-

53 344 Beuzelin et al. tion preference include leaf pubescence, as shown for Diatraea saccharalis (Fabricius) (Sosa, 1990), and green leaf volatiles, as shown for Chilo partellus Swinhoe (Birkett et al., 2006; Midega et al., 2011). The study of physical and chemical characteristics potentially affecting E. loftini oviposition preference will assist in better understanding the insect s biology and help identify host plant resistance traits. Our study is the first to show that E. loftini larvae infesting rice, brome, and ryegrass develop faster than those infesting johnsongrass and vaseygrass. Although van Leerdam (1986) found that female larval development was slower than that of males, such differences were not detected in our study. Van Leerdam (1986) estimated that larvae feeding on sugarcane (cv. NCo 310) stalk sections completed development in 519 ºD>14.6 C for females and 392 ºD>14.9 C for males in the laboratory. The fastest larval development in our study was 540 ºD, which occurred when neonates infested rice at the panicle exertion stage. Thus, E. loftini larval development might be shorter on sugarcane than on rice and the four non-crop hosts of our study. Physical constraints associated with stem diameter may impact E. loftini immature performance because larger stems are more suitable for development (Showler et al., 2011). Nevertheless, the large-stemmed perennials in our study were less suitable as E. loftini hosts than rice and annuals that had relatively narrow stems. In addition, E. loftini larvae were observed feeding within stems but also extensively through stem walls of rice and annuals. These observations suggest that physical factors allowing larvae to escape stem diameter constraints may influence E. loftini immature performance. Martin et al. (1975) and Keeping & Rutherford (2004) showed that sugarcane internode rind hardness is a source of larval antibiosis for the stem borers D. saccharalis and Eldana saccharina Walker. Stem fiber and relative lignin contents may also affect larval feeding and development (Rutherford et al., 1993). Host plant nutritional quality is another key factor in determining E. loftini immature performance. Increased FAA concentrations have been consistently associated with enhanced nutritional quality of herbivore host plants (Showler, 2001; Reay-Jones et al., 2007a; Showler & Castro, 2010a). However, the quantification of FAA concentrations in rice and four primary non-crop hosts in our study did not help explain differences in E. loftini larval development durations. Nevertheless, studies utilizing varying nitrogen fertilization levels to change host plant nutritional quality demonstrated impacts on herbivore immature performance. Greater total nitrogen content in cotton, Gossypium hirsutum L., shortened immature development duration in S. exigua (Chen et al., 2008). For Sesamia calamistis Hampson feeding on maize, Zea mays L., greater stem and leaf nitrogen concentrations increased larval survival and pupal weight (Setamou et al., 1993). Increases in plant total nitrogen and FAA concentrations result in greater survival, weight, and shorter development duration for E. saccharina larvae on sugarcane (Atkinson & Nuss, 1989). Although exact mechanisms enhancing immature performance for S. exigua, S. calamistis, and E. saccharina are undetermined, changes in plant FAA and nitrogen content, nitrogen to carbohydrate ratio, and potential decreases in defensive compounds are likely involved (Atkinson & Nuss, 1989; Setamou et al., 1993; Chen et al., 2008). Similar to these three lepidopteran herbivores, exact causes for differences in E. loftini immature performance as affected by host plant species and phenology have not been determined. In addition to FAAs, host plant-specific carbohydrate composition (AT Showler, unpubl.), nitrogen to carbohydrate ratio, and allelochemicals certainly impact nutritional quality. For example, johnsongrass produces dhurrin (Nicollier et al., 1983), a cyanogenic glucoside associated with decreased herbivory (Woodhead & Bernays, 1978). For crambid and pyralid stem borers, the relationship between oviposition preference and immature performance on crop, forage, and weedy plants seems speciesspecific. In our study, E. loftini moths preferred laying eggs on rice, which was also the most suitable host, allowing relatively shorter larval development. However, brome and ryegrass, which seemed more suitable as E. loftini hosts than johnsongrass and vaseygrass, were the least preferred hosts. Showler et al. (2011) showed that increased E. loftini oviposition preference for corn, compared with sorghum, Sorghum bicolor (L.) Moench, and sugarcane, was associated with increased performance, as measured by the number of adult exit holes. In the same study, oviposition preference and immature performance were greater on johnsongrass than on vaseygrass. Eldana saccharina shows oviposition preference for wild graminoid hosts as compared to corn (Atachi et al., 2005; Conlong et al., 2007). However, performance is inversely associated with preference on these hosts, with longer immature development, lower survival, and lower pupal weight observed on wild grasses than on corn (Shanower et al., 1993; Atachi et al., 2005). Chilo partellus consistently prefers Pennisetum purpureum Schumach., a forage grass, for oviposition (Ofomata et al., 2000; van den Berg et al., 2001; Midega et al., 2011). However, immature survival is extremely low on this grass (Ofomata et al., 2000; van den Berg et al., 2001). The time a herbivore is exposed to a new host, the relative abundance of hosts, the herbivore feeding habits, and

54 Oviposition and larval development of Eoreuma loftini 345 the suppression from natural enemies as affected by the host apply the selection pressure shaping the relationship between preference and performance (Thompson, 1988). Presumably native to northwest Mexico, E. loftini expanded its range into eastern Mexico before it was introduced into south Texas, from where it spread along >600 km of Gulf Coast within 30 years (Reay-Jones et al., 2007b). During this range expansion, E. loftini has likely been exposed to substantial changes in relative abundance of graminaceous crops, non-crop graminoids, and natural enemies. Eoreuma loftini preference and performance in our study are the results of changing selection pressures and could not have been predicted. In addition, preference and performance may vary within and among populations (Thomspon & Pellmyr, 1991; Assefa et al., 2009). Thus, the study of both preference and performance along with governing morphological and biochemical factors will continue to be needed to identify sources and sinks of E. loftini populations in agroecosystems. Our study provided insights on aspects of E. loftini oviposition preference and immature performance, which impact egg partitioning among primary hosts and the length of larval development on these hosts in Texas Gulf Coast rice agroecosystems. Host selection can be predicted based on oviposition preference and host availability using equation (3) (Wilson & Gutierrez, 1980; Murphy et al., 1991; Reay-Jones et al., 2007a). Similarly, larval development duration can be used to predict E. loftini dynamics on primary hosts. However, host-specific survival and fecundity, which are key performance parameters impacting population dynamics, have not been determined. In addition, potential E. loftini larval movement and preference, which may substantially impact larval mortality and infestations when hosts occur in mixture, have not been documented. Together with previous research (Reay-Jones et al., 2007a; Beuzelin et al., 2011a; Showler et al., 2011), our study contributes to a foundation for a pest management strategy based on the prediction of the relative contribution of multiple host plants to E. loftini populations in rice agroecosystems. Acknowledgments This work was supported by USDA CSREES Crops- At-Risk IPM program grant and USDA NIFA AFRI Sustainable Bioenergy program grant We thank David Blouin, Mike Stout, Rita Riggio, Bill White, Lee Tarpley, Ronnie Porter, Veronica Abrigo, Jaime Cavazos, Becky Pearson, Sebe Brown, Jannie Castillo, and Jiale Lv for their technical assistance. We thank David Blouin, Mike Stout, and Eric Webster for participating in the review of the manuscript. This study is approved for publication by the Director of the Louisiana Agricultural Experiment Station as manuscript number References Assefa Y, van den Berg J, Mitchell A, Le R u BP & Conlong DE (2009) Record of Eldana saccharina Walker (Lep, Pyralidae) in inland South Africa and its genetic relationship with the coastal population. Journal of Applied Entomology 133: Atachi P, Sekloka ET & Schulthess F (2005) Study on some bioecological aspects of Eldana saccharina Walker (Lep., Pyralidae) on Zea mays L. and alternative host plants. Journal of Applied Entomology 129: Atkinson PR & Nuss KJ (1989) Associations between host-plant nitrogen and infestations of the sugarcane borer, Eldana saccharina Walker (Lepidoptera: Pyralidae). Bulletin of Entomological Research 79: van den Berg J, Rebe M, De Bruyn J & Van Hamburg H (2001) Developing habitat management systems for gramineous stemborers in South Africa. Insect Science and Its Application 21: Beuzelin JM, Meszaros A, Reagan TE, Wilson LT, Way MO et al. (2011a) Seasonal infestations of two stem borers (Lepidoptera: Crambidae) in non-crop grasses of Gulf Coast rice agroecosystems. Environmental Entomology 40: Beuzelin JM, Reagan TE, Way MO, Meszaros A, Akbar W & Wilson LT (2011b) Potential impact of Mexican rice borer non-crop hosts on sugarcane IPM. International Sugar Journal 113: Birkett MA, Chamberlain K, Khan ZR, Pickett JA, Toshova T et al. (2006) Electrophysiological responses of the lepidopterous stemborers Chilo partellus and Busseola fusca to volatiles from wild and cultivated host plants. Journal of Chemical Ecology 32: Chapman RF (1998) The Insects: Structure and Function, 4th edn. Cambridge University Press, New York, NY, USA. Chen Y, Ruberson JR & Olson DM (2008) Nitrogen fertilization rate affects feeding, larval performance, and oviposition preference of the beet armyworm, Spodoptera exigua, on cotton. Entomologia Experimentalis et Applicata 126: Conlong DE, Kasl B & Byrne M (2007) Independent kids or motherly mom? Implications for integrated management of Eldana saccharina Walker (Lepidoptera: Pyralidae). Proceedings of the International Society of Sugar Cane Technologists 26: Hummel NA, Hardy T, Reagan TE, Pollet DK, Carlton CE et al. (2010) Monitoring and first discovery of the Mexican rice borer Eoreuma loftini (Lepidoptera: Crambidae) in Louisiana. Florida Entomologist 93: SAS Institute (2002) JMP User s Guide, Version 5. SAS Institute, Cary, NC, USA. Keeping MG & Rutherford RS (2004) Resistance mechanisms of South African sugarcane to the stalk borer Eldana saccharina

55 346 Beuzelin et al. (Lepidoptera: Pyralidae): a review. Proceedings of the South African Sugar Technologists Association 78: van Leerdam MB (1986) Bionomics of Eoreuma loftini, apyralid Stalk Borer of Sugarcane. PhD Dissertation, Texas A&M University, College Station, TX, USA. Martin FA, Richard CA & Hensley SD (1975) Host resistance to Diatraea saccharalis (F.): relationship of sugarcane internode hardness to larval damage. Environmental Entomology 4: Martinez AJ, Baird J & Holler T (1988) Mass rearing sugarcane borer and Mexican rice borer for production of parasites Allorhogas pyralophagus and Rhaconotus roslinensis. USDA- ARS-PPQ, APHIS, Meagher RL Jr, Irvine JE, Breene RG, Pfannenstiel RS & Gallo- Meagher M (1996) Resistance mechanisms of sugarcane to Mexican rice borer (Lepidoptera: Pyralidae). Journal of Economic Entomology 89: Midega CAO, Khan ZR, Pickett JA & Nylin S (2011) Host plant selection behaviour of Chilo partellus and its implication for effectiveness of a trap crop. Entomologia Experimentalis et Applicata 138: Murphy BC, Wilson LT & Dowell RV (1991) Quantifying apple maggot (Diptera: Tephritidae) preference for apples to optimize the distribution of traps among trees. Environmental Entomology 20: Nicollier GF, Pope DF & Thompson AC (1983) Biological activity of dhurrin and other compounds from Johnson grass (Sorghum halepense). Journal of Agricultural and Food Chemistry 31: Ofomata VC, Overholt WA, Lux SA, van Huis A & Egwuatu RI (2000) Comparative studies on the fecundity, egg survival, larval feeding, and development of Chilo partellus and Chilo orichalcociliellus (Lepidoptera: Crambidae) on five grasses. Annals of the Entomological Society of America 93: Reay-Jones FPF, Way MO, Setamou M, Legendre BL & Reagan TE (2003) Resistance to the Mexican rice borer (Lepidoptera: Crambidae) among Louisiana and Texas sugarcane cultivars. Journal of Economic Entomology 96: Reay-Jones FPF, Showler AT, Reagan TE, Legendre BL, Way MO & Moser EB (2005) Integrated tactics for managing the Mexican rice borer (Lepidoptera: Crambidae) in sugarcane. Environmental Entomology 34: Reay-Jones FPF, Wilson LT, Showler AT, Reagan TE & Way MO (2007a) Role of oviposition preference in an invasive crambid impacting two graminaceous host crops. Environmental Entomology 36: Reay-Jones FPF, Wilson LT, Way MO, Reagan TE & Carlton CE (2007b) Movement of the Mexican rice borer (Lepidoptera: Crambidae) through the Texas rice belt. Journal of Economic Entomology 100: Rutherford RS, Meyer JH, Smith GS & van Staden J (1993) Resistance to Eldana saccharina (Lepidoptera: Pyralidae) in sugarcane and some phytochemical correlations. Proceedings of the South African Sugar Technologists Association 67: SAS Institute (2008) User s Manual, Version 9.2. SAS Institute, Cary, NC, USA. Setamou M, Schulthess F, Bosque-Perez NA & Thomas-Odjo A (1993) Effect of plant nitrogen and silica on the bionomics of Sesamia calamistis (Lepidoptera: Noctuidae). Bulletin of Entomological Research 83: Shanower TG, Schulthess F & Bosque-Perez N (1993) The effect of larval diet on the growth and development of Sesamia calamistis Hampson (Lepidoptera: Noctuidae) and Eldana saccharina Walker (Lepidoptera: Pyralidae). Insect Science and Its Application 14: Showler AT (2001) Spodoptera exigua oviposition and larval feeding preferences for pigweed, Amaranthus hybridus, over squaring cotton, Gossypium hirsutum, and a comparison of free amino acids in each host plant. Journal of Chemical Ecology 27: Showler AT (2012) Drought and arthropod pests of crops. Droughts: New Research (ed. by DF Neves & JD Sanz), pp Nova Science Publishers, Hauppauge, NY, USA. Showler AT & Castro BA (2010a) Influence of drought stress on Mexican rice borer (Lepidoptera: Crambidae) oviposition preference in sugarcane. Crop Protection 29: Showler AT & Castro BA (2010b) Mexican rice borer (Lepidoptera: Crambidae) oviposition site selection stimuli on sugarcane, and potential field applications. Journal of Economic Entomology 103: Showler AT & Reagan TE (2012) Ecology and tactics of control for three sugarcane stalkboring species in the Western Hemisphere and Africa. Sugarcane: Production, Cultivation and Uses (ed. by JF Goncalves & KD Correia), pp Nova Science Publishers, Hauppauge, NY, USA. Showler AT, Beuzelin JM & Reagan TE (2011) Alternate crop and weed host plant oviposition preferences by the Mexican rice borer (Lepidoptera: Crambidae). Crop Protection 30: Sosa O Jr (1990) Oviposition preference by the sugarcane borer (Lepidoptera: Pyralidae). Journal of Economic Entomology 83: Thompson JN (1988) Evolutionary ecology of the relationship between oviposition preference and performance of offspring in phytophagous insects. Entomologia Experimentalis et Applicata 47: Thompson JN & Pellmyr O (1991) Evolution of oviposition behavior and host preference in Lepidoptera. Annual Review of Entomology 36: Van Zwaluwenburg RH (1926) Insect enemies of sugarcane in western Mexico. Journal of Economic Entomology 19: Wilson LT & Gutierrez AP (1980) Fruit predation submodel: Heliothis larvae feeding upon cotton fruiting structures. Hilgardia 48: Woodhead S & Bernays EA (1978) The chemical basis of Sorghum bicolor to attack by Locusta migratoria. Entomologia Experimentalis et Applicata 24:

56 APPENDIX A: INSECT NURSERY SITE MAP Sorghum Fertilization Study Appendix C Bioenergy Test Multiple Infestation Levels Appendix B Host Plant Resistance Test 2012 Appendix D Host Plant Resistance Test 2011 Appendix D 26 Rows 23 Rows 7 Rows 5 Rows North Canal

57 Sugarcane & Energycane planted on 11/2/11 Sorghum planted on 4/20/2012 APPENDIX B: BIOENERGY TEST 2012 AND 2013 PLOT PLAN 2 row/bed Approx 20 in row spacing 1 seed every 3.6 in Approx. 1 in deep Variety Test Buffer 15 ft < ft 72 ft R M81E 5200 R4 5 ft 72 ft R M81E R3 5 ft 72 ft R M81E R2 5 ft 72 ft R M81E 113 R1 5 ft Buffer 15 ft < 838 Rows --> CANAL CANAL CANAL CANAL CANAL CANAL CANAL CANAL CANAL CANAL CANAL CANAL

58 Buffer 1 row M81E 1-row Buffer M81E Appendix C: Beaumont Fertilization Trial 2013-Sorghum Buffer 12.5 ft M81E Rep 4 75 ft Gap 10 ft Rep 3 Gap Rep 2 75 ft 10 ft 75 ft Total Length = 355 ft Gap 10 ft Rep 1 75 ft M81E ES5200 ES5140 ES5200 M81E ES5140 M81E ES5140 ES5200 ES5140 ES5200 M81E Buffer 12.5 ft M81E row Test Field 26 rows (24 test, 2 buffer) 330 ft Main Plot 6 rows 75 ft Fertilization Rates Sub plots 2 rows 75 ft control (no nitrogen) 40 lbs N/A (low 80 lbs N/A (medium) 120 lbs N/A (high)

59 US APPENDIX D: BEAUMONT VARIETY TEST 2011 PLOT PLAN N V IV III II I US HoCP Ho L L Ho Ho HoL L L L Ho HoCP HoCP Ho HoCP Ho L HoCP Ho blank L L blank L Ho Ho HoL L HoCP HoCP Ho Ho Ho HoCP Ho HoCP HoCP L L Ho HoCP L L Ho HoL L Ho Ho Ho HoCP HoCP blank HoCP HoCP L Ho Ho L Ho L L L L L HoL Ho Ho L blank Ho HoCP Ho Ho HoCP HoCP HoCP Ho L Ho HoCP L L blank Ho L Ho Ho L Ho L L HoCP Ho HoL HoCP HoCP Ho Ho HoCP HoCP US Plot size = 1 row, 5.25 ft row width, 12 ft long with 4 ft alley Buffer rows on north (6 ft), south (6 ft) and east (1 row) ends of test

60 APPENDIX D: BEAUMONT VARIETY TEST 2012 PLOT PLAN 1 B O R D E R R O W H O C P V IV III II I North ~30ft HoCP Ho TCP TCP Ho Ho TCP Ho CP CP L Ho Ho L Ho Ho L L HoCP HoCP Ho Ho Ho L L Ho L CP Ho TCP Ho L CP TCP HoCP HoCP Ho Ho Ho Ho Ho Ho TCP HoCP L Ho HoCP Ho CP L Ho TCP Ho CP Ho TCP Ho Ho Ho Ho Ho L TCP L CP CP Ho L Ho Ho Ho L TCP Ho L TCP Ho Ho Ho L Ho HoCP Ho TCP HoCP TCP CP L TCP CP HoCP Ho Ho Ho Ho Ho TCP Ho L Ho Ho Ho HoCP L L Ho ~12ft HoCP Plot size: 1 Row, 5.25 ft width, 12ft long with 4 ft alleys Buffer rows north (6 ft), south (6ft), and 1 row on the east and west borders B O R D E R R O W H O C P

61 APPENDIX E: SUNGRANT 2010 PLOT MAP

62 APPENDIX E: SUNGRANT 2010 PLOT MAP

63 APPENDIX E: SUNGRANT 2008 PLOT MAP