Potential for Phytotoxicity of Pennant Magnum 7.62 EC (s-metalochlor) on Transvaal Daisy (Gerbera jamesonii Lambada )

Transcription

1 Potential for Phytotoxicity of Pennant Magnum 7.62 EC (s-metalochlor) on Transvaal Daisy (Gerbera jamesonii Lambada ) By Heiner Lieth, Director Linda Dodge Ron Lane Dylan Hodgkiss Project Interregional Research Project #4 Project Number A September 23, 25 Donors/Supporters Terra Nigra Inc., Carpinteria CA UC Davis Environmental Horticulture IR4 Center Department of Plant Sciences University of California One Shields Ave. Davis, CA http//envhort.ucdavis.edu/ir4

2 TRIAL DATE 9/23/5 Investigator (Name, Address, Phone#, e- mail, etc) Dr. Heiner Lieth Department of Plant Sciences University of California One Shields Ave. Davis, CA Ph FAX Location of Trial TRIAL TYPE (field, container, greenhouse, etc) University of California, Davis CA Field Container Chemical - Common Name s-metalochlor - Formulation 7.62% EC - Batch Number - Product Pennant Magnum 7.62 EC - EPA Registration Number Manufacture Syngenta USE INFORMATION - Plant Common Name Transvaal Daisy - Plant Scientific Name Gerbera jamesonii Lambada - Pest (s) Weeds Soil Type or Type of Potting Mix UC Mix a)%sand 35 b)%silt c)%clay d)%om 65 e)%ph 6.5 Enter each DATE for Seedling Emergence Transplanting 7/18/25 Enter each SPACING for Enter each SIZE for Experimental Design Number of Reps Plant or Pot 6 inches Row 6 inches Pot 6-inch Plot 5 sq ft Randomized complete block (3 blocks X 3 reps) 9 reps total for each treatment 2

3 TRIAL DATE 9/23/5 APPLICATION PARAMETERS1 Type of Application (aerial, ground, foliar, drench, ppi, chemigation, broadcast, directed, etc) Number of Applications Application Type Foliar spray 2, 3 days apart Manual spray bottle Nozzle Type/Size Nozzle Pressure Delivery Rate Calibration Date(s) APPLICATION SUMMARY APPLICATION DATE RATES (a.i./a) (Be sure to provide units) Brief Description of Growth Stage (Dormant, New Growth Present, Bud, etc) July 29, 25, 2.5, 5, 1 lb. a.i./a Vegetative/flowering, actively growing August 26, 25, 2.5, 5, 1 lb. a.i./a Vegetative/flowering, actively growing 1 RAINFALL/IRRIGATION RECORDS INCLUDE RAINFALL/IRRIGATION INFORMATION (printouts, IR-4 forms, etc.) See Table 1 for environmental conditions. The plants were watered daily with tap water using a drip irrigation system delivering 1 gallon per hour. 3

4 TRIAL DATE 9/23/5 OTHER PESTICIDES, FERTILIZER, LIME AND ADJUVANTS USED PRODUCT AMOUNT DATE Osmocote tsp per 6-inch pot 8/12/25 Pounce.16 oz/2 gal 8/26/25 Marathon II 2.4 oz/2 gal 8/26/25 NARRATIVE SUMMARY OF METHODS AND RESULTS Materials and Methods Plant Material and Culture. Liners of Gerbera jamesonii Lambada were received from Terra Nigra Nursery on July 15, 25. These were transplanted to 6-inch pots containing UC Mix on July 18, 25 and grown on in a greenhouse for 1 days. The 8-week experiment took place in an outdoor nursery and began on July 29, 25. Environmental conditions during the experiment are summarized in Table 1. Osmocote ( ) controlled release fertilizer was added on August 12, 25 at the rate of.5 teaspoon per 6-inch pot. The plants were watered daily during the 8-week experiment with tap water using a drip irrigation system delivering 1 gallon per hour. Applications of pesticides as part of a normal pest management program were made as needed (see above). Experimental Procedure. Thirty-six plants were randomly chosen and individually tagged for treatment with (Control), 2.5 (1X), 5 (2X), or 1 (4X) lb. ai/a Pennant Magnum 7.62 EC with 9 replicates per treatment. These dosages were prescribed in IR4 Ornamental Protocol 5-1 dated 1/5 (Appendix A). The plants received the first foliar spray application on July 29, 25 and the second application 4 weeks later on August 26, 25. The plants were arranged in a randomized complete block design with 3 blocks and 3 treatment replicates per block. Phytotoxicity ratings and plant height and width measurements were taken at day, 3, 7, 14, 28, 31, 35, 42 and 56. Visual phytotoxicity evaluations were based on a numerical rating scale ranging from (no injury) to 1 (complete kill) (Table 2). Because of mechanical damage on the liners during shipment, nearly all plants were given initial damage ratings of 1. Plant height (cm) was measured from the container soil surface to the top of the leaf canopy (excluding flower scapes). Plant width (cm) was measured twice along perpendicular lines at the widest part of the plant, resulting in W 1 and W 2. For each observation a canopy volume index was calculated so as to be able to determine if canopy volume was affected by the application of Pennant Magnum 7.62 EC. The calculation was made as H*W 1 *W 2, where H is the height and W 1 and W 2 are two width measurements. The usefulness of this index is based on the fact that many of the models for such a volume calculation are of the form a*h*w 1 *W 2. The constant a depends on the assumption of the shape of the canopy. Since analyses of variance are scale-independent, the conclusion will thus be for the volume of the plant canopy. Statistical Analysis. The data were analyzed using Proc GLM of the Statistical Analysis System (SAS). The phytotoxicity and change in mean value from the starting plant height, width and volume index were analyzed for significant differences using t-tests. 4

5 TRIAL DATE 9/23/5 Results During the first two weeks of the trial no changes in phytotoxicity index were noted for most of the Gerbera plants resulting in a uniform index reading of 1. for most plants (Table 3, Figures 1 and 2, Appendix B). As a consequence no statistical methods are needed (or possible) to identify that the herbicide had no phytotoxicity effect on any of the plants during this time. By week 4, however, significant (although small) differences in the change in phytotoxicity index were noted. During the second half of the trial, after the second application, further phytotoxicity index value increases were noted in the plants to which Pennant was applied. By week 8 a pattern was evident with ever-increasing degrees of phytotoxicity with increasing dosage of the herbicide. Phytotoxicity symptoms included necrotic patches on leaves and distortion or puckering of new growth (Figure 1). All Gerbera plant growth variables showed a significant negative effect due to Pennant (Table 4, Figures 2 and 3, Appendix B). At the 1X rate, the height increased only 8.1 cm over the trial, compared with 15.3 cm for the control. There was little or no height increase of the plants in the 2X and 4X treatments. The same pattern was evident in plant width increase. Volume index showed the same pattern the canopy volume increase in the 1X treatment was only 36% of the canopy volume increase of the control while the plants in the 2X and 4X treatments had no increase in canopy volume. Discussion Pennant caused both phytotoxicity and growth suppression on Gerbera. The effect is severe at the 2X and 4X rates of application. The effect is less severe at the 1X rate but even at this rate the growth reduction is so severe as to suggest that Pennant is not safe for use on Gerbera. GOOD RESEARCH PRACTICE STATEMENT I acknowledge that I have read and followed the IR-4 Research protocol and completed this trial following good agricultural practice, or reported any deviations (note any changes from authorized protocol in narrative). SIGNATURE (PRINCIPAL INVESTIGATOR) Date Completed If submitted, using , please provide address and send confirming receipt. 5

6 TRIAL DATE 9/23/5 Date Table 1. Environmental conditions during the experiment to evaluate the phytotoxicity of Pennant Magnum 7.62 EC on Gerbera jamesonii Lambada. Sol Rad (Ly/day) Max Air Temp ( F) Min Air Temp ( F) Avg Air Temp ( F) Avg Vap (mbars) Avg wspd (MPH) Precip (in) CIMIS ETo (in) Avg Rel Hum (%) Dew Pt ( F) 7/29/ /3/ /31/ /1/ /2/ /3/ /4/ /5/ /6/ /7/ /8/ /9/ /1/ /11/ /12/ /13/ /14/ /15/ /16/ /17/ /18/ /19/ /2/ /21/ /22/ /23/ /24/ /25/ /26/ /27/ /28/ /29/ /3/ /31/ /1/ /2/ /3/ /4/ /5/ /6/ /7/ /8/ /9/ /1/ /11/ /12/ /13/ /14/ /15/ /16/ /17/ /18/ /19/ /2/ /21/ /22/ /23/

7 TRIAL DATE 9/23/5 Table 2. Numerical plant damage rating scale used for phytotoxicity determinations. Rating Description of plant damage No damage 1 No visible damage but unintended (non-permanent) impact 2 Slight leaf/tissue damage (curling leaves, necrosis, etc.) 3 Marginal chlorosis on some leaves (damage on up to 1% of plant) 4 1% 2% of plant damaged 5 Significant damage to much of plant (3% - 4%) 6 4% 6% of plant damaged 7 Chlorosis or necrosis on most of plant (6% - 7%) 8 Abscised leaves, branch dieback 9 Tissue severely damaged (8% - 1% of plant) 1 Complete kill Table 3. Phytotoxicity ratings over 8 weeks for Gerbera jamesonii Lambada treated with (Control), 2.5 (1X), 5 (2X), or 1 (4X) lb. ai/a Pennant Magnum 7.62 EC, applied at weeks and 4. Different letters within a column indicate significant differences between treatments (P <.5). Yes / No refer to significant treatment effects at the 5% level. Means ± SE (n = 9) Phytotoxicity Effect of Pennant on Gerbera Phytotoxicity Index Increase from beginning of trial until Treatment Day 3 (NA) 1 week (NA) 2 weeks (NA) 4 weeks yes X. ±. a. ±. a. ±. a -.11 ±.11 b 1X. ±. a. ±. a. ±. a.56 ±.24 a 2X. ±. a. ±. a. ±. a.56 ±.18 a 4X. ±. a. ±. a. ±. a.89 ±.2 a Phytotoxicity Index increase from beginning of trial until Treatment Day 3 of week4 yes 5 week yes 6 weeks yes 8 weeks yes X -.11 ±.11 b. ±. c. ±. c. ±. d 1X 1. ±.24 a 1. ±.24 b 1.11 ±.2 b 1.22 ±.22 c 2X 1.56 ±.18 a 1.44 ±.18 ab 1.44 ±.18 ab 3.22 ±.36 b 4X 1.56 ±.24 a 1.78 ±.22 a 1.78 ±.22 a 5. ±.29 a Table 4. Plant height, width and volume changes over 8 weeks for Gerbera jamesonii Lambada treated with (Control), 2.5 (1X), 5 (2X), or 1 (4X) lb. ai/a Pennant Magnum 7.62 EC, applied at weeks and 4. Different letters within a column indicate significant differences between treatments (P <.5). Yes / No refer to significant treatment effects at the 5% level. Means ± SE (n = 9) Growth Effect of Pennant on Gerbera Increase by week 8 of Average Width (cm) yes Volume Index yes Treatment Height (cm) yes X ± 1.49 a 9.19 ± 2.6 a ± a 1X 8.11 ± 2.31 b 5.25 ± 2.33 ab ± b 2X.89 ± 1.78 c ± 1.53 c ± c 4X -.44 ± 1.8 c -.89 ± 1.85 bc ±274.4 c 7

8 TRIAL DATE 9/23/5 Figure 1. Phytotoxicity symptoms seen on Gerbera jamesonii Lambada plants 8 weeks after treatment with 2.5 lb. ai/a (1X rate) at left and 1 lb. ai/a (4X rate) at right of Pennant Magnum 7.62 EC. Foliar spray applications were made at week and week 4. Symptoms included necrotic patches on leaves and distortion or puckering of new growth. 8

9 TRIAL DATE 9/23/5 Species Gerbera -- Material Pennant Height (cm) Ctrl 1X 2X 4X Day of trial Change (cm) Phytotoxicity Index Control 1X 2X 4X Day of trial Width (cm) Ctrl 1X 2X 4X Day of trial Change (cm) Volume Index Ctrl 1X 2X 4X Day of trial Change Figure 2. Summary of results for Gerbera jamesonii Lambada treated with (Control), 2.5 (1X), 5 (2X), or 1 (4X) lb. ai/a Pennant Magnum 7.62 EC, applied at weeks and 4 (arrows). Both means and cumulative changes over time are plotted for phytotoxicity index, plant height, plant width and plant volume index. Histograms show changes over the 8-week trial period. SE bars shown. (n = 9) 9

10 TRIAL DATE 9/23/5 Block A Block B CONTROL 1X 2X 4X Block C Figure 3. Gerbera jamesonii Lambada plants 8 weeks after treatment with (Control), 2.5 (1X), 5 (2X), or 1 (4X) lb. ai/a Pennant Magnum 7.62 EC, applied at weeks and 4. 1

11 TRIAL DATE 9/23/5 Appendix A Phytotoxicity to herbaceous perennial plants with pre-emergent applications of Pendulum, Pennant Magnum, and Snapshot Ornamental Protocol Number 5-1 Objective Determine phytotoxicity of Pendulum, Pennant Magnum, and Snapshot to unlabelled perennial plants commonly grown in nurseries. Experimental Design Plot Size Must be adequate to reflect actual use conditions. Replicates Minimum of 3 replications (preferably 4) with 3 pots per replicate Application Instructions Two applications made approximately 4 weeks apart with the first application within 7 days of potting. Plant materials must have broken dormancy prior to first application. For liquid applications, use a minimum of 2 gal per acre. Applications should be made over the top of the plants using application equipment consistent with conventional commercial equipment. Please see table below for instructions for post-application irrigation. Plant Materials See attached list of plant materials. Plants grown in field containers are preferred to in-ground. Evaluations Record phytotoxicity on a scale of to 1 ( = No phytotoxicity; 1 = Complete kill)at 3, 7, 14, and 28 days after each application. If phytotoxicity is observed in treated plants, take pictures comparing treated and untreated plant material. Recordkeeping Keep detailed records of weather conditions including temperature and precipitation, soil-type or soil-less media, application equipment, application volume per acre, irrigation, liner size, plant height & width, and plant growth stage at application and data collection dates. Treatments Product Rate Post-Application Irrigation Instructions Pennant Magnum 7.62 EC (pendimethalin) 2. lb ai/a 4. lb ai/a Follow with sufficient overhead irrigation to wash Pendulum from the foliage to reduce 8. lb ai/a the chance of injury Pennant MAGNUM 7.62EC (s-metalochlor) 2.5 lb ai/a 5. lb ai/a Follow with sufficient overhead irrigation to wash Pennant Magnum from the foliage to 1. lb ai/a reduce the chance of injury Snapshot 2.5TG (isoxaben+trifluralin) 2.5 lb ai/a Follow with sufficient overhead irrigation to 5. lb ai/a 1. lb ai/a wash Snapshot from the foliage to reduce the chance of injury Untreated For labels, materials, and any required adjuvants contact Pendulum - BASF, Kathie Kalmowitz, , kalmowk@basf-corp.com Pennant Magnum - Syngenta, Dave Ross, , david.ross@syngenta.com Snapshot - Dow AgroSciences, Mike Melichar, , mwmelichar@dow.com Reports Report must include a brief summary paragraph of results, a summary table with appropriate statistical analyses, a section on experimental design and materials and methods, with raw data and recordkeeping information as listed above included as appendices. If pictures were taken, please include them. An electronic report is preferred but not required. If the report is provided electronically, the basic report can be sent in MS Word or WordPerfect, the recordkeeping information as pdf or other electronic documents, and the raw data in MS Excel or other suitable program such as ARM. Please direct questions to Cristi Palmer, IR-4 HQ, Rutgers University, 681 US Hwy 1 S, North Brunswick, NJ , Phone x629, palmer@aesop.rutgers.edu OR Ely Vea, 38 Aston Forest Lane, Crownsville, MD 2132, Phone & FAX# , evvea@comcast.net. 11

12 TRIAL DATE 9/23/5 Appendix B Phytotoxicity Report Form for Pennant on Gerbera Phytotoxicity at week Plant Size at week Plant Size at week 8 day day Height Width1 Width 2 Height Width1 Width 2 Treatment Block Rep (cm) (cm) (cm) (cm) (cm) (cm) Control A Control A Control A Control B Control B Control B Control C Control C Control C Mean X A X A X A X B X B X B X C X C X C Mean X A X A X A X B X B X B X C X C X C Mean X A X A X A X B X B X B X C X C X C Mean