SMALL PLOT ASSESSMENT OF INSECTICIDES AGAINST THE SUGARCANE BORER, 2009

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1 SMALL PLOT ASSESSMENT OF INSECTICIDES AGAINST THE SUGARCANE BORER, 2009 T. E. Regn, W. Akbr, B. E. Wilson, J. Hmm, nd J. M. Beuzelin Deprtment of Entomology Six different insecticide tretments, in ddition to n untreted check, were ssessed for seson-long control of the sugrcne borer (SCB) in rndomized complete block design RCBD with five replictions in field of vriety HoCP plntcne ner Burns Point, L. Insecticide tretments were pplied to 3-row plots (24 ft) on July 7 nd August 6, Tretments were mixed in 2 gllons of wter nd pplied using Solo bck pck spryer delivering 40 gp t 20 psi. Borer injury to sugrcne ws ssessed by counting the totl number of internodes (12 stlks/plot), number of bored internodes nd moth emergence holes in ech stlk t the time of hrvest (October 13). The proportion of bored internodes nd emergence holes were nlyzed using generlized liner mixed model (Proc Glimmix, SAS Institute) with binomil distribution for percentge of bored internodes nd Poisson distribution for number of exit holes per plot. The mens were seprted with Tukey s HSD ( = 0.05). The percentge of bored internodes in the treted plots rnged between 1-5% nd ws significntly less thn the 28% observed in the untreted check (Tble 1). Corgen t 5.0 oz/cre rte showed trend for the most reduction in internode dmge; however, significnt differences were not detected mong the insecticide tretments. The numbers of exit holes mde by the prepup in the stlks were lso lower in ll insecticide tretments thn in the untreted check (Tble 1). Tble 1. Insecticidl control of the sugrcne borer in smll plot test ner Burns Point, LA. Tretment Rte (oz/cre) % Bored Internodes/plot Exit Holes/stlk Check b Confirm b 0.05 Belt b 0.13 Bythroid b 0.14 Belt b 0.14 Dimond b 0.10 Corgen b 0.10 Insecticide tretments were pplied with Induce surfctnt t 0.5% v/v. Mens within column followed by the sme letter re not significntly different (P.05, Tukey s HSD). 102

2 SMALL PLOT ASSESSMENT OF WIREWORM CONTROL IN SUGARCANE, 2009 T. E. Regn, W. Akbr, J. M. Beuzelin, nd B. E. Wilson Deprtment of Entomology Three new environmentlly friendly insecticides long with Mocp (ethoprop), n orgnophosphte, were compred to the untreted check for wireworm control ner Burns Point, L. Whole stlks of vriety HoCP were plnted on September 29, The tretment plots consisted of three 24 ft rows with 10 ft gps between plots, with totl of 5 replictions. The grnulr formultions were mixed with corn cob grits for even distribution of the chemicl. Liquid formultions were mixed in wter nd spryed using bckpck spryer. The number of shoots emerged in the center row of ech plot ws counted on December 8, 2008 nd gin on April 7, Plots were hrvested in Jnury 2010 using combine hrvester, nd the centrl row of ech plot ws weighed nd smpled to ssess yield. Differences were not detected in the number of shoots emerged by December April smpling indicted the highest numbers of shoots in plots treted with liquid Corgen (rynxypyr), significntly greter thn the grnulr formultion but not from the untreted check or other insecticide tretments. Cne nd sugr yields rnged from tons/cre nd lbs/ton, respectively, with no differences mong tretments (Tble 1). In contrst to severl rice studies with treted seed, this experiment did not show ny systemic ctivity with Corgen ginst the sugrcne borer. Tble 1. Soil insecticides trgeting wireworm injury on sugrcne emergence nd yield. Tretment Formultion Rte Shoots/cre Dec 08 Apr 09 Yield (ton/cre) Sugr (lbs/ton) Admire Pro b Liquid 14 14,037 41,820 b Mocp Liquid 20 16,457 43,078 b NUQ05055 Grnulr ,005 44,676 b Corgen Liquid 7 14,279 45, Corgen Grnulr 21 13,117 38,722 b Control - 13,746 39,884 b oz/cre for liquid formultion, lbs/cre for grnulr formultion; b ctive ingredient is imidcloprid Mens within column followed by the sme letter re not significntly different (P.05, Tukey s HSD). 103

3 EVALUATION OF AERIAL INSECTICIDAL CONTROL OF THE MEXICAN RICE BORER IN SUGARCANE, 2009 T. E. Regn 1, Blke E. Wilson 1, Wseem Akbr 1, Julien Beuzelin 1, nd A.T. Showler 2 1 Deprtment of Entomology nd 2 USDA-ARS Weslco, Texs Evlution of eril insecticidl control of the Mexicn rice borer (MRB), Eoreum loftini, ws conducted in lrge re Rndomized Block Design (RBD) with five replictions. Insecticide tretments were ssigned rndomly to plots (10 cres/plot) in fields rnging from cres of vriety CP first stubble cne in the Lower Rio Grnde Vlley (Cmeron County, Texs). Pheromone-trp-ssisted-scouting ws used to monitor MRB popultion densities nd effectively time the need for insecticide pplictions. Trp ctches of >20-25 moths/trp/week were used s scouting threshold to initite monitoring for lrvl infesttions (Tble 1). Tretble lrvl infesttions (present in lef sheths) were determined by collecting two ten stlk smples per plot. Infesttions rnged from 5.0 to 32.1% with men of 13.8% stlks infested (Tble 1) on 20 Aug. Applictions were mde the morning of 21 Aug by fixed wing ircrft t 10 GPA with less thn 5 mph wind. Bored internode nd emergence hole counts were recorded on 28 Oct; 30 stlks from two loctions (15 - front, 15 - bck) per tretment plot were smpled. The recently lbeled (Section 3 for sugrcne) environmentlly friendly insecticide, Dimond (MANA), pplied t 12oz/ showed the best control with 6.9% bored internodes, which ws significntly less thn both the untreted plots (20.4% bored) nd the Bythroid (2.8oz/) treted plots (Figure 1). Bythroid (Byer) treted plots (12.6% bored) were not significntly different from untreted plots (Figure 1). Differences in moth emergence followed the sme trend lthough significnt differences were not detected mong tretments (Figure 2). Results indicte tht Dimond provided superior control to the trditionlly used pyrethroid insecticide, Bythroid (Byer). This study demonstrtes the potentil of pheromone-trpssisted-scouting to reduce scouting effort nd optimlly time insecticide pplictions. Ongoing reserch will determine if insecticide tretments incresed subsequent sugrcne yields nd will further correlte dult densities to lrvl infesttion levels. This reserch is portion of the M.S. Thesis progrm of Blke Wilson in the Deprtment of Entomology. 104

4 Tble 1: Seson long pheromone trp ctches. Number of mle MRB moths per trp % Infesttion Field # 7/1 5 7/2 2 7/2 9 8/5 8/1 2 8/1 9 8/20 1d y 8/2 6 9/ 2 9/9 9/1 6 9/2 3 10/1 4 8/ live lrvl infesttions in lef sheth 105

5 30 Figure 1: Percent Bored Internodes Men % Bored Internodes b 0 Untreted Bythroid Dimond Dt ws nlyzed using generlized liner mixed model with binomil distribution. F=16.37, Df=2,7.2, P= Mens were seprted using Tukey s HSD (P 0.05). Figure 2: Moth Emergence 1 Emergence per stlk Untreted Bythroid Dimond Dt ws nlyzed using generlized liner mixed model with Poisson distribution. F=.71; Df=2,7.1; P= Mens were seprted using Tukey s HSD (P 0.05). 106

6 OVIPOSITION PREFERENCE AND IMMATURE DEVELOPMENT OF THE MEXICAN RICE BORER ON MAJOR NON-CROP HOSTS T.E. Regn, J.M Beuzelin, L.T. Wilson*, A.T. Showler*, A. Meszros, nd B.E. Wilson Deprtment of Entomology A greenhouse experiment ws conducted t the Texs A&M AGRILife Reserch nd Extension Center t Beumont, TX to determine the oviposition preference nd durtion of development of Mexicn rice borers (MRB) on primry non-crop hosts s ffected by plnt species nd stge. An nnul crop grss, rice (cv. Cocodrie), two perennil grsses (johnsongrss, vseygrss), nd two nnul grsses (brome, ryegrss) were used. Plntings were scheduled to obtin the different phenologicl stges t the sme time. Rice nd the perennils were evluted t three phenologicl stges while the nnuls were evluted t two phenologicl stges for totl of 13 plnt species by phenology combintions (Tble 1). This experiment ws rrnged s complete rndomized block design with cges (n = 13) used s blocks. Cges (1.3 m by 1.3 m by 1.80m) were constructed from 1.27 cm PVC nd covered with fine white mesh cloth. Ech cge contined ll of the 13 plnt species by phenology combintions. Ten MRB femles nd 5-10 MRB mles (mted, c. 36h old), obtined from USDA Weslco, TX colony were relesed in ech cge between 6:00 nd 7:00 PM. Prior to MRB dult relese in the cges, plnt fresh weight ws determined using seprte smples of 5 representtive plnts from ech of the 13 plnt species by phenology combintions. Three dys fter dult relese, ech plnt ws inspected nd the number of eggs recorded. In this study, 95%< of the eggs were lid on dry plnt mteril. Oviposition preference ws expressed s the proportion of totl eggs lid per grm of plnt fresh weight. Rice plnts consistently hd the gretest proportion of eggs (Fig. 1). Johnsongrss nd vseygrss received 2-3 fold fewer eggs thn rice, wheres brome received n insignificnt proportion of the eggs. MRB did not ly eggs on ryegrss. A greter proportion of eggs were lid on intermedite nd older plnts (Fig. 1), likely ssocited with the incresed vilbility of dry folige. Plnts were dissected for MRB lrve nd pupe 6 weeks fter oviposition determintion. Under greenhouse experimentl conditions, substntil interplnt movement of erly MRB instrs ws observed, nd ll of the 13 plnt species by phenology combintions were infested with borers. Recovered lrve nd pupe were rered in the greenhouse on rtificil diet until dult eclosion. For ech recovered MRB immture, full development durtion ws estimted. Becuse the development of cold-blooded orgnisms such s insects is temperture dependent, development durtions were expressed in physiologicl time. The minimum temperture when development occurs is clled the lower developmentl threshold (T L ), nd the physiologicl time needed for development is expressed in degree-dys ( D) bove T L tht re ccumulted: Development time in D = (Dily temperture-t L ) Development time in dys *L.T. Wilson is ffilited with the Texs A&M University Center t Beumont, TX. A.T. Showler is ffilited with the USDA-ARS Kik de l Grz Reserch Center t Weslco, TX. This reserch is prt of the Ph.D. disserttion reserch progrm of Julien Beuzelin 107

7 A lower developmentl threshold T L = 14.5 C nd development time of 576 D on rtificil diet ws determined from previous studies on MRB biology (vn Leerdm 1986). Becuse MRB lrve nd pupe recovered fter plnt dissection were rered on rtificil diet until dult emergence, development time completed on diet fter plnt dissection ws recorded, nd full development durtion on plnt until dult emergence could be estimted. MRB development ws the fstest on rice (Fig. 2) lthough brome nd ryegrss were lso suitble hosts. Development on johnsongrss nd vseygrss slowest (Fig. 2), 1.6 nd 1.5-fold slower thn on rice, respectively. Trends for slower development on younger plnts were observed. Previous multi-re trnsect studies showed tht non-crop hosts could ply key role in MRB popultion dynmics nd identified primry non-crop hosts. This greenhouse study quntified MRB egg lying nd lrvl development on rice nd primry non-crop grsses. This quntifiction provides better understnding of MRB ecology nd will ssist in the development of mngement tctics impcting non-crop hosts. Tble 1. Plnt species by development stge combintions tested in greenhouse experiment ssessing MRB oviposition nd immture development durtion on mjor non-crop hosts. Rice (Oryz stiv) Johnsongrss (Sorghum hlepense) Vseygrss (Psplum urvillei) Brome (Bromus spp.) Ryegrss (Lolium spp.) Young plnts Intermedite plnts (ge in weeks fter plnting) Old plnts Reference cited: Vn Leerdm, M. B Bionomics of Eoreum loftini, pyrlid stlk borer of sugrcne. PhD disserttion, Texs A&M University, College Sttion, TX. 108

8 % totl eggs / g fresh weight ± SE bcd b d bc b cd bcd bcd Young d d Intermedite d d Old Fig. 1 MRB oviposition preference on rice nd primry non-crop hosts SAS Proc MIXED: Plnt species: P<0.001, Stge(Plnt species): P<0.001 Brs with the sme letter re not significntly different (Tukey s HSD, = 0.05) Young Intermeditee Old Development durtion in D ± SE b bc 1400 b d b bc 1200 b bcd bc bcd 1000 bc c c Fig. 2 MRB immture development durtion on rice nd primry non-crop hosts SAS Proc MIXED: Plnt species: P<0.001, Stge(Plnt species): P=0.006 Brs with the sme letter re not significntly different (Tukey s HSD, = 0.05) 109

9 SMALL PLOT ASSESSMENT OF INSECTICIDES AGAINST THE MEXICAN RICE BORER T. E. Regn, J. M. Beuzelin,W. Akbr, nd B. E. Wilson Deprtment of Entomology A study ws conducted t the Texs A&M University reserch site t Gndo, TX (Jckson County) to evlute insecticides for mngement of the Mexicn rice borer (MRB) in sugrcne. Four insecticide tretments, in ddition to n untreted check, were ssessed for seson-long control of MRB. The experiment ws rrnged following rndomized complete block design (RCBD) with 4 replictes nd 1-row plots (15 ft ech, cultivr Ho ) plnted in Nov Insecticides were pplied to plots on 19 Jun, 22 Jul, nd 20 Aug, Insecticides were mixed in 2 gl of wter nd pplied using Solo bckpck spryer delivering 10 gp t 14 psi. MRB injury ws ssessed by recording the number of bored internodes nd the totl number of internodes from 12 stlks per plot t the time of hrvest (24 Sep, 2009). MRB moth production recorded s the no. dult emergence holes for ech stlk ws lso ssessed. The proportion of bored internodes nd emergence hole frequency were nlyzed using generlized liner mixed models (Proc GLIMMIX, SAS Institute) with binomil nd Poisson distributions, respectively. Mens were seprted using Tukey s HSD. Under extremely hevy MRB infesttions (c. 65% bored internodes in the untreted control), Belt decresed MRB injury to greter extent thn Dimond (Tble 1). However, MRB control with Belt ws not different from tht observed with Bythroid. Confirm pplictions were not ssocited with significnt decreses in MRB injury. Numericl trends (P 0.10) for differences in no. moth emergence holes indicte tht in ddition to decresing MRB injury, insecticides hve the potentil to decrese the production of MRB popultions. Tble 1. Insecticidl control of Mexicn rice borer, smll plot test t Gndo, TX, Insecticide Rte (oz/) % Bored Internodes (LSMens ± SE) b No. emergence holes / stlk (LSMens ± SE) b Bythroid ± 4.81 bc 0.46 ± 0.18 Belt ± 2.32 c 0.00 ± 0.00 Confirm ± 6.79 b 0.83 ± 0.30 Dimond ± 5.34 b 0.60 ± 0.22 Check NA ± ± 0.35 F vlue p vlue < All tretments were pplied with the nonionic surfctnt Induce t 0.25% v/v. b Mens within columns followed by the sme letter re not significntly different (P.05,Tukey s HSD). 110