IR-4 Ornamental Horticulture Program Research Report Form

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1 Project Title: Phytotoxicity of BroadStar 0.25G (VC1604) applied over the top to selected woody ornamental plants (August 2008 trials) Protocol #: Narrative Summary (Results/Discussion) Note: The protocol for this material states: Do not apply at the first application timing within 7 days after potting; only apply at the second application timing. For these experiments, two applications of BroadStar 0.25G were made 6 weeks apart. The first application occurred 10 weeks after potting for Hydrangea, 14 weeks after potting for Ilex and 6 weeks after potting for Nepeta. Hydrangea Phytotoxicity. The Hydrangea plants suffered heat stress during the fist 2-3 weeks of the trial (Table 4) resulting in damage rating increases for the control that rose on average from 0.8 to 2.9 by week 7 Tables 1 and 6a, Figure 1). Thus all plants were significantly blemished. The plants treated with Broadstar had significantly greater mean phytotoxicity index values at all weeks compared to the control plants. The symptoms observed included leaf necrosis and death of terminal buds. Thus it can be concluded that Broadstar it not safe over Hydrangea. Plant Growth. There was considerable variation in growth among the Hydrangea plants so that no significant treatment effect was noted for height or width increase (Tables 2 and 6a, Figure 2a). In general the average values for these variables were negative indicating that all plants became reduced in dimensions due to leaf necrosis. Ilex Phytotoxicity and Plant Growth. The control plants had average phytotoxicity mean values of 0 at all observation dates (Tables 1 and 6b, Figure 1). There were no treatment effects on each observation date. The plants in the 1X, 2X, and 4X treatment all were not significantly different from the control and no mean value for any to these three treatments was ever over 0.3. There were no significant treatment effects on any of the growth variables (Tables 2 and 6b, Figure 2b). We can conclude that BroadStar is safe when applied over Ilex. Nepeta The Nepeta plants in the control group had average phytotoxicity index values less then 1 at all observation dates (Tables 1 and 6c, Figure 1). Significant treatment effects were noted at all observation dates after week 6. The phytotoxicity index values for the 1X treatment averaged below 1 up to week 4; thereafter these rose to around 3 by week 10. The plants treated with Broadstar at 1X level had significantly greater phytotoxicity levels than the control. The plants in the 2X and 4X treatments generally had more phytotoxicity than either the control or 1X treatment. Symptoms included chlorosis and necrosis of older leaves. 1

2 Plant Growth. Nepata plants in the control group grew 5.9 cm in height and 16.8 cm in width (Tables 2 and 6c, Figure 2c). There was a significant treatment effect due to Broadstar; plants exposed to the herbicide grew less in height and width. The calculated volume index showed that even at the 1X level, plants were significantly smaller. The growth of Nepeta was suppressed significantly in all Broadstar treatments. Broadstar is not safe for use over Nepeta at any of the concentrations tested. Materials & Methods: Plant Material and Culture. The plants for these trials were grown as indicated in Table 3. The experiment ran from August 14, 2008 to October 23, 2008 in an outdoor nursery full sun. The plants were irrigated daily during the 10-week experiment using an automatic overhead sprinkler system delivering 1.5L per hour. Environmental conditions during the trial are indicated in Table 4. Experimental Procedure. Thirty-six plants were randomly chosen and individually tagged for treatment with 0 (Control), 1X, 2X or 4X rates of the herbicide with 9 replicates per treatment. These dosages were prescribed in IR4 Ornamental Protocol (Appendix A). The plants received the first application on August 14, 2008 and the second application 6 weeks later on September 25, Data Collection. Phytotoxicity ratings were taken at week 0, 1, 2, 4, 6, 7, 8, and 10.The dates for those observations were August 14, 21, 28, September 11, 25, October 2, 9, and 23, Visual phytotoxicity evaluations were based on a numerical rating scale ranging from 0 (no injury) to 10 (complete kill) (Table 5). Plant height and width were measured at week 0 (August 14, 2008) and week 10 (October 23, 2008). Plant height (cm) was measured from the container soil surface to the top of the canopy. 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 herbicide. 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. 2

3 Acknowledgements: The research was supported through funding from the USDA IR-4 Program, Western Region based at UC Davis, Davis, CA. Personnel involved in this project included Linda Dodge (trial coordination, data collection, report compilation), Ron Lane (pesticide application, pest management), Marian Shahid, Jennifer Orsi, Katie Gross, Hsin Yi Cheng, Yan Zhaung and Dylan Portnoff (plant culture, data collection). The materials being tested were supplied by the manufacturer/distributor. The plants were supplied by Monrovia Nursery, Visalia CA. 3

4 Table 1. Phytotoxicity changes over 10 weeks for plants treated with 0 (Control), 150 (1X), 300 (2X) or 600 (4X) lb. per acre BroadStar 0.25G at weeks 0 and 6. Differing letters a, b, c designate significant differences among the four means; "Yes" or "no" indicates whether there was an overall significant treatment effect at the 5% level (NA means no variation in data; "yes at 10%" means treatment effect was significant at 10% but not at the 5% level). Means ± SD (n=9) Phytotoxicity Effect of BroadStar on Hydrangea PR# Phytotoxicity Index Increase from beginning of trial until: Treatment 1 week yes 2 weeks yes 4 weeks yes 6 weeks no 7 weeks no 8 weeks no 10 week yes 0X 0.78 ± 0.28 b 0.89 ± 0.35 b 1.11 ± 0.35 b 2.33 ± 0.44 b 2.89 ± 0.56 b 2.89 ± 0.56 b 2.56 ± 0.50 b 1X 2.33 ± 0.50 a 2.89 ± 0.45 a 3.89 ± 0.82 a 4.00 ± 0.78 a 4.33 ± 0.73 a 4.33 ± 0.73 a 4.56 ± 0.71 a 2X 1.67 ± 0.41 ab 2.89 ± 0.31 a 2.78 ± 0.28 a 3.33 ± 0.17 ab 3.33 ± 0.17 ab 3.33 ± 0.17 ab 4.22 ± 0.15 a 4X 2.33 ± 0.24 a 3.22 ± 0.22 a 3.89 ± 0.20 a 4.00 ± 0.29 a 4.33 ± 0.17 a 4.33 ± 0.17 a 4.67 ± 0.29 a Phytotoxicity Effect of BroadStar on Ilex PR# Phytotoxicity Index Increase from beginning of trial until: Treatment 1 week no 2 weeks no 4 weeks (NA) 6 weeks (NA) 7 weeks no 8 weeks no 10 week no 0X 0.00 ± 0.00 a 0.00 ± 0.00 a 0.00 ± 0.00 a 0.00 ± 0.00 a 0.00 ± 0.00 a 0.00 ± 0.00 a 0.00 ± 0.00 a 1X 0.00 ± 0.00 a 0.00 ± 0.00 a 0.00 ± 0.00 a 0.00 ± 0.00 a 0.00 ± 0.00 a 0.00 ± 0.00 a 0.00 ± 0.00 a 2X 0.11 ± 0.11 a 0.11 ± 0.11 a 0.00 ± 0.00 a 0.00 ± 0.00 a 0.22 ± 0.22 a 0.22 ± 0.22 a 0.22 ± 0.22 a 4X 0.00 ± 0.00 a 0.00 ± 0.00 a 0.00 ± 0.00 a 0.00 ± 0.00 a 0.00 ± 0.00 a 0.00 ± 0.00 a 0.11 ± 0.11 a Phytotoxicity Effect of BroadStar on Nepeta PR# Phytotoxicity Index Increase from beginning of trial until: Treatment 1 week no 2 weeks yes 4 weeks yes 6 weeks yes 7 weeks yes 8 weeks yes 10 week yes 0X 0.00 ± 0.00 a 0.00 ± 0.00 b 0.00 ± 0.00 c 0.33 ± 0.33 c 0.67 ± 0.44 c 0.44 ± 0.29 c 0.89 ± 0.35 c 1X 0.00 ± 0.00 a 0.00 ± 0.00 b 0.22 ± 0.22 c 1.89 ± 0.20 b 2.89 ± 0.26 b 2.89 ± 0.26 b 3.00 ± 0.29 b 2X 0.22 ± 0.22 a 0.33 ± 0.17 a 0.89 ± 0.35 b 2.11 ± 0.35 b 3.11 ± 0.20 ab 3.11 ± 0.20 b 3.22 ± 0.22 ab 4X 0.00 ± 0.00 a 0.00 ± 0.00 b 2.00 ± 0.00 a 3.56 ± 0.24 a 3.89 ± 0.11 a 3.89 ± 0.20 a 3.89 ± 0.20 a 4

5 Species: Hydrangea Material: BroadStar 10 Control 1X 8 2X 4X 6 Phytotoxicity Index 4 2 Species: Ilex Material: BroadStar 10 Control 1X 8 2X 4X 6 Phytotoxicity Index Day of trial Day of trial Species: Nepeta Material: BroadStar 10 Control 1X 8 2X 4X Phytotoxicity Index Day of trial Figure 1. Phytotoxicity ratings for plants exposed to two applications of 0 (Control), 150 (1X), 300 (2X) or 600 (4X) lb. per acre BroadStar 0.25G at weeks 0 and 6 (arrows). See Table 5 for explanation of ratings. 5

6 Table 2. Growth changes over 10 weeks for plants treated with 0 (Control), 150 (1X), 300 (2X) or 600 (4X) lb. per acre BroadStar 0.25G at weeks 0 and 6. Differing letters a, b, c designate significant differences among the four means; "Yes" or "no" indicates whether there was an overall significant treatment effect at the 5% level (NA means no variation in data; "yes at 10%" means treatment effect was significant at 10% but not at the 5% level). Means ± SD (n=9) Growth Effect of BroadStar Increase by week 10 of: Crop Treatment Height (cm) no Average Width (cm) no Volume Index no Hydrangea 0X ± 1.29 a ± 1.16 a ± a PR# X ± 0.78 a ± 0.83 ab ± ab 2X ± 0.73 a ± 1.52 b ± b 4X ± 0.60 a ± 0.71 ab ± ab Treatment Height (cm) no Average Width (cm) no Volume Index no Ilex 0X 1.61 ± 0.58 a 0.56 ± 0.48 a ± a PR# X 1.17 ± 0.44 a 0.36 ± 0.77 a ± a 2X 0.89 ± 0.63 a 1.69 ± 0.66 a ± a 4X ± 1.26 a 0.42 ± 0.42 a ± a Treatment Height (cm) yes Average Width (cm) yes Volume Index yes Nepeta 0X 5.94 ± 0.71 a ± 1.66 a ± a PR# X 4.33 ± 0.91 a 9.58 ± 1.12 b ± b 2X 3.78 ± 1.23 a 8.08 ± 1.64 b ± b 4X 1.17 ± 0.61 b 8.03 ± 1.58 b ± b 6

7 Block A Block B CONTROL 1X 2X 4X Block C Figure 2a. Hydrangea plants 10 weeks after two applications of 0 (Control), 150 (1X), 300 (2X) or 600 (4X) lb. per acre BroadStar 0.25G at weeks 0 and 6. 7

8 Block A Block B CONTROL 1X 2X 4X Block C Figure 2b. Ilex plants 10 weeks after two applications of 0 (Control), 150 (1X), 300 (2X) or 600 (4X) lb. per acre BroadStar 0.25G at weeks 0 and 6. 8

9 Block A Block B CONTROL 1X 2X 4X Block C Figure 2c. Nepeta plants 10 weeks after two applications of 0 (Control), 150 (1X), 300 (2X) or 600 (4X) lb. per acre BroadStar 0.25G at weeks 0 and 6. 9

10 Table 3. Materials & Methods/Recordkeeping Protocol number Product Short Name BroadStar 0.25G (VC1604) BroadStar 0.25G (VC1604) BroadStar 0.25G (VC1604) Production Field Container Field Container Field Container Site Description PR Number Crop Latin Hydrangea sp. Ilex vomitoria Nepeta X faassenii Name Crop Common Hydrangea Dwarf Yaupon Holly Catmint Name Crop Cultivar none Plant Source Propagated from UCD stock plants Propagated from UCD stock plants Propagated from UCD stock plants Transplant 2008_06_ _05_ _07_05 Date Potting Mix UC Mix UC Mix UC Mix Pot Size 1-gallon 1-gallon 1-gallon Spacing Pot-to-pot Pot-to-pot Pot-to-pot Expt. Design RCB RCB RCB Number of Reps 3 blocks with 3 reps per block = 9 3 blocks with 3 reps per block = 9 3 blocks with 3 reps per block = 9 Fertilizer Type Osmocote Osmocote Osmocote Fertilizer 2008_06_ _05_ _07_05 Application Date Irrigation type and frequency automatic overhead sprinklers daily automatic overhead sprinklers daily automatic overhead sprinklers daily First 2008_08_ _08_ _08_14 Application and Measurements Date Second 2008_09_ _09_ _09_25 Application Date Final Measurements Date 2008_10_ _10_ _10_23 10

11 Table 4. Environmental conditions during the experiment from 2008_08_14 to 2008_10_23 Date Net Rad Max Air Min Air Avg Vap Avg Precip CIMIS Avg Rel (Ly/day) Temp Temp (mbars) wspd (in) ETo (in) Hum (%) ( F) ( F) (MPH) 8/14/ /15/ /16/ /17/ /18/ /19/ /20/ /21/ /22/ /23/ /24/ /25/ /26/ /27/ /28/ /29/ /30/ /31/ /1/ /2/ /3/ /4/ /5/ /6/ /7/ /8/ /9/ /10/ /11/ /12/ /13/ /14/ /15/ /16/ /17/ /18/ /19/ /20/ /21/ /22/ /23/ /24/ /25/ /26/ /27/ /28/ /29/ /30/ /1/ /2/ /3/ /4/

12 10/5/ /6/ /7/ /8/ /9/ /10/ /11/ /12/ /13/ /14/ /15/ /16/ /17/ /18/ /19/ /20/ /21/ /22/ /23/ Table 5. Numerical plant damage rating scale used for phytotoxicity determinations. Rating Description of plant damage 0 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 10% of plant) 4 10% 20% of plant damaged 5 Significant damage to much of plant (30% - 40%) 6 40% 60% of plant damaged 7 Chlorosis or necrosis on most of plant (60% - 70%) 8 Abscised leaves, branch dieback 9 Tissue severely damaged (80% - 100% of plant) 10 Complete kill 12

13 Table 6a Raw Data for Hydrangea Phytotoxicity Report Form Hydrangea Broadstar IR4 Trial Phytotoxicity at week Plant Size at week 0 Plant Size at week 10 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

14 Table 6b Raw Data for Ilex Phytotoxicity Report Form Ilex Broadstar IR4 Trial Phytotoxicity at week Plant Size at week 0 Plant Size at week 10 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

15 Table 6c Raw Data for Nepeta Phytotoxicity Report Form Nepeta Broadstar IR4 Trial Phytotoxicity at week Plant Size at week 0 Plant Size at week 10 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

16 Appendix A 2008/2009 Crop Safety with Over-the-top Applications of Select Herbicide Materials Ornamental Protocol Number: Objective: Determine phytotoxicity of BAS 656EC, BAS 659G, Broadstar 0.25G VC1604, BroadStar 0.25G, and V G to woody ornamental plants and BAS 659G on herbaceous perennials. Experimental Design: Plot Size: Must be adequate to reflect actual use conditions. Replicates: Minimum of 3 replications (preferably 4) with 3 plants per replicate Application Instructions: Depending upon research site and plant materials, various experiments can be established. Two applications are to be made approximately 6 weeks apart, with the first application within 7 days after potting, preferable between 24 and 48 hours. However, plant materials must have broken dormancy prior to first application. See notes below for Broadstar New Formulation. For liquid applications, use a minimum of 20 gal per acre. Applications should be made over the top of the plants using application equipment consistent with conventional commercial equipment. For all materials, target dry foliage. If dew is present at the time of application, note it. Irrigate with ½ inch water between 1 and 4 hours after application. Note: Liquid materials need at least 1 hour drying time prior to irrigation. Plant Materials: Contact your Regional Coordinator for an up-to-date list. Plants grown in field containers are preferred to in-ground. Evaluations: Record plant height & width at initial and final evaluations only. At 1, 2, and 4 weeks after each application, record phytotoxicity on a scale of 0 to 10 (0 = No phytotoxicity; 10 = Complete kill). If appropriate, also include ratings for chlorosis, defoliation, stunting or other growth effects on a scale of 0 to 10 (0 = No effect; 10 = Complete plant affected). If any 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, irrigation, liner size, plant height & width, and plant growth stage at application and data collection dates. Treatments: Product Rate Special Instructions Contact Information to obtain materials BAS 656h 63.9%EC (dimethenamid-p) BAS 659h 1.75G (dimethenamid-p + pendimethalin) Broadstar 0.25G VC1604 BroadStar 0.25G 21 fl oz per acre (0.97 lb ai) 42 fl oz per acre (1.94 lb ai) 84 fl oz per acre (3.88 lb ai) 150 lb per acre (2.65 lb ai 300 lb per acre (5.3 lb ai) 600 lb per acre (10.6 lb ai) 150 lb per acre (0.375 lb ai) 300 lb per acre (0.75 lb ai) 600 lb per acre (1.5 lb ai) 100 lb product per acre (2.1 lb ai/a) 200 lb product per acre (4.2 lb ai/a 300 lb product per acre (6.3 lb ai/a) Woody ornamentals only BASF, Kathie Kalmowitz, , kathie.kalmowitz@basf.com Do not apply at the first application timing within 7 days after potting; only apply at the second application timing. BASF, Kathie Kalmowitz, , kathie.kalmowitz@basf.com Valent, Joe Chamberlin, , jcham@valent.com Woody ornamentals only Syngenta, Nancy Rechsigl, , nancy.rechcigl@syngenta.com V G 150 lb per acre (0.75 lb ai/acre) 300 lb per acre (1.5 lb ai/acre) 600 lb per acre (3.0 lb ai/acre) Untreated Valent, Joe Chamberlin, , jcham@valent.com 16