IR-4 Ornamental Horticulture Program Trial Report

Transcription

1 Project Title: Evaluation of phytotoxicity of V-1142 on American Arborvitae (Thuja occidentalis Emerald Green ) IR4 PR#: Report date: November 21, 26 Authors: Heiner Lieth and Linda Dodge Department of Plant Sciences University of California, Davis Davis, CA Narrative Summary: Thuja occidentalis Emerald Green plants growing in 1-gallon containers received two applications of V-1142 at.5 lb ai/acre (1X), 1. lb ai/acre (2X) or 2. lb ai/acre (4X) rates as described in the Materials and Methods section of this report. The interval between applications was 4 weeks. The plants in the Control group received no V The trial was conducted over 8 weeks from April 14, 26 to June 6, 26. The phytotoxicity index levels of the Thuja occidentalis Emerald Green plants exposed to V at all rates were high enough to render the plants unmarketable. Phytotoxicity was present at all rates of application and became apparent 4 weeks after the first application. There was a significant growth retardation effect by the product. V-1142 should not be used over the top on Thuja occidentalis Emerald Green. 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: Ron Lane (pesticide application, pest management) and Melaku Sebhatu (plant culture, data collection). The materials being tested were supplied by the manufacturer/distributor. Plants were provided by Monrovia Nursery, Visalia CA. 1

2 Overview of Trial and Protocol: The trial was conducted according to the IR4 protocol # 6-1 (Appendix A). The details are listed in the section, below, entitled Materials and Methods/Recordkeeping. Phytotoxicity ratings were recorded at weeks, 1, 2, 4, 5, 6 and 8. Phytotoxicity was evaluated using a Phytotoxicity index, consisting of a scale where values of 1 or below represent negligible blemishes and values above 3 represent damage that renders the plant unmarketable. Plant height and width measurements were taken at the beginning and end of the trial. Plant growth evaluations include a calculated Volume index which is proportional to the canopy volume. Results: Phytotoxicity index means showed no treatment effects for V-1142 on Thuja occidentalis Emerald Green during the first 3 weeks (Tables 1 and 3, Figure 1). Subsequently, there was a significant increase in the phytotoxicity index in all treatments where plants were exposed to V It should be noted that the absolute phytotoxicity index levels for the V-1142 treated plants were between 3 and 5 during weeks 4 through 8 (Figure 2a). Phytotoxicity symptoms included branch tip dieback (Figure 2b). Over the 8 week growing period, the Thuja occidentalis Emerald Green plants in the control group grew an average of 7 cm taller and 1.4 cm wider resulting in a volume index increase of 1454 (Tables 2 and 3, Figures 1 and 3). The plants treated with V-1142 at all rates grew significantly less with mean height increase of less than 2 cm and width decreases of to 1 cm in all cases. The volume index changes due to the V-1142 treatments were negative for all rates of application. Discussion: The phytotoxicity index levels of the Thuja occidentalis Emerald Green plants exposed to V at all rates were high enough to render the plants unmarketable. Phytotoxicity was present at all rates of application and became apparent 4 weeks after the first application. There was a significant growth retardation effect by the product. V-1142 should not be used over the top on Thuja occidentalis Emerald Green. 2

3 Materials & Methods/Recordkeeping: Crop History Crop Cultivar/Variety: Date of Seeding: Date of Emergence: American Arborvitae (Thuja occidentalis Emerald Green ) Date of Transplanting: Liners received from Monrovia 3/16/6, transplanted 3/2/6 Potting Mix: Pot size & spacing: Row spacing: UC Mix: 1/3 sand, 1/3 peat, 1/3 bark (by volume) 1-gallon pots spaced on 12-inch centers Product(s) applied prior to start of experiment: Product Rate Application Type Date of Application Crop Growth Stage Application Volume Osmocote tsp./pot Manual 4/4/6 Actively growing NA Experiment Information Experimental Design: Number of Reps: Randomized complete block 9 (3 blocks x 3 reps per block) Materials & Methods: Plant Material and Culture. Liners of Thuja occidentalis Emerald Green were received from Monrovia Nursery, Visalia CA, on March 16, 26. The plants were transplanted to 1-gallon pots containing UC Mix on March 2, 26. The experiment ran from April 14, 26 to June 6, 26 in an outdoor nursery under 5% shade (Table 4). The plants were irrigated 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 below). Experimental Procedure. Thirty-six plants were randomly chosen and individually tagged for treatment with (Control),.5 lb ai/acre (1X), 1. lb ai/acre (2X) or 2. lb ai/acre (4X) V-1142 with 9 replicates per treatment. These dosages were prescribed in IR4 Ornamental Protocol 6-1 (Appendix A). The plants received the first foliar spray application on April 14, 26 and the second application 4 weeks later on May 12, 26. 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. 3

4 Application Equipment: Manual spray bottles for V-1142 Product(s) applied during experiment (including treatments, fertilizers, etc): Product Rate(s) Application Type Date of Application Crop Growth Stage V , 1., 2. Foliar spray 4/14/6 Actively growing lb ai/acre V , 1., 2. Foliar spray 5/12/6 Actively growing lb ai/acre Application Volume Data Collected: Data Collection. Phytotoxicity ratings were taken at week, 1, 2, 4, 5, 6 and 8, (April 1, 18 and 25, 26; May 9, 15 and 24, 26; June 6, 26). Visual phytotoxicity evaluations were based on a numerical rating scale ranging from (no injury) to 1 (complete kill) (Table 5). Plant height and width were measured at week (April 1, 26) and week 8 (June 6, 26). 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. 4

5 Table 1. Phytotoxicity changes over 8 weeks for Thuja occidentalis Emerald Green treated with (Control),.5 (1X), 1. (2X) or 2. (4X) lb ai/acre V-1142 at weeks and 4. Different letters within a column indicate significant differences between treatments (P <.5). Yes / No designations refer to significant treatment effects at the 5% level. Means ± SE (n=9) Phytotoxicity Effect of V-1142 on Thuja Phytotoxicity Index Increase from beginning of trial until: Treatment 1 week (NA) 2 weeks (NA) 4 weeks yes X. ±. a. ±. a. ±. b 1X. ±. a. ±. a 3.78 ±.28 a 2X. ±. a. ±. a 3.67 ±.37 a 4X. ±. a. ±. a 4.22 ±.4 a Phytotoxicity Index increase from beginning of trial until: Treatment 5 week yes 6 weeks yes 8 weeks yes X. ±. b.44 ±.18 b.67 ±.17 c 1X 4. ±.37 a 4. ±.44 a 3.89 ±.31 b 2X 3.89 ±.35 a 4. ±.33 a 4. ±.33 ab 4X 4.44 ±.47 a 4.89 ±.42 a 4.78 ±.36 a Table 2. Plant height, width and volume changes over 8 weeks for Thuja occidentalis Emerald Green treated with (Control),.5 (1X), 1. (2X) or 2. (4X) lb ai/acre V-1142 at weeks and 4. Different letters within a column indicate significant differences between treatments (P <.5). Yes / No designations refer to significant treatment effects at the 5% level. Means ± SE (n=9) Growth Effect of V-1142 on Thuja Increase by week 8 of: Treatment Height (cm) yes Average Width yes Volume Index yes (cm) X 7. ±.45 a 1.44 ±.3 a ± a 1X 1.61 ±.35 b -.5 ±.26 b ± b 2X 1.39 ±.18 b -1.3 ±.52 b ± b 4X.89 ±.25 b -.33 ±.14 b ± b 5

6 Raw Data: Table 3. Phytotoxicity and plant growth data collected for plants of Thuja occidentalis Emerald Green treated with two applications of (Control),.5 (1X), 1. (2X) or 2. (4X) lb ai/acre V-1142 at weeks and 4 of an 8-week experiment. Phytotoxicity Report Form Thuja V-1142 IR4 Trial Phytotoxicity at week Plant Size at week Plant Size at week 8 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

7 Environmental conditions during the experiment: Table 4. Environmental conditions during the experiment to determine phytotoxicity of V-1142 on Thuja occidentalis Emerald Green. Date Sol Rad (Ly/day) Max Air Temp ( F) Min Air Temp ( F) Avg Vap (mbars) Avg wspd (MPH) Precip (in) CIMIS ETo (in) Avg Rel Hum (%) 4/14/ /15/ /16/ /17/ /18/ /19/ /2/ /21/ /22/ /23/ /24/ /25/ /26/ /27/ /28/ /29/ /3/ /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 Table 5. 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 8

9 Species: Thuja -- Material: V-1142 Height (cm) Change (cm) Phytotoxicity Index Control 1X 2X 4X 15 Ctrl 1X 2X 4X Day of trial Day of trial Width (cm) 1 5 Ctrl 1X 2X 4X Day of trial Change (cm) Volume Index Ctrl 1X 2X 4X Day of trial Change Figure 1. Summary of results for Thuja occidentalis Emerald Green treated with (Control),.5 (1X), 1. (2X) or 2. (4X) lb ai/acre V-1142 at weeks and 4. 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 Phytotoxicity Ratings Figure 2a. Examples of phytotoxicity ratings given to plants of Thuja occidentalis Emerald Green 8 weeks after 2 applications of V Figure 2b. Branch tip dieback seen on Thuja occidentalis Emerald Green 8 weeks after 2 applications of.5 lb ai/acre (1X) V

11 Block A Block B CONTROL 1X 2X 4X Block C Figure 3. Thuja occidentalis Emerald Green 8 weeks after two applications of (Control),.5 (1X), 1. (2X) or 2. (4X) lb ai/acre V-1142 at weeks and 4. 11

12 APPENDIX A Phytotoxicity to ornamental horticulture plants from tools to manage broadleaf weeds and sedges. Ornamental Protocol Number: 6-1 Objective: Determine phytotoxicity of Manage (halosulfuron), Sulfentrazone.2G, and V-1142 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 plants per replicate Application Instructions: Apply first application over the top of plants just breaking dormancy or, under climates where plants do not go totally dormant, apply prior to active growth in the spring. See table for product specific information. Plant Materials: See attached list of plant materials. Plants grown in field containers are preferred to in-ground. Evaluations: Record plant height & width at initial and final evaluations. At 1, 2, and 4 weeks after each application, record phytotoxicity on a scale of to 1 ( = No phytotoxicity; 1 = Complete kill). If appropriate, also include ratings for chlorosis, defoliation, stunting or other growth effects on a scale of to 1 ( = No effect; 1 = Complete plant affected). If any phytotoxicity is observed in treated plants, take pictures comparing treated and untreated plant material. If different application methods or evaluations are made, please clearly specify differences in final report and explain how they enhanced results. 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 Rates Special Instructions Contact Information to obtain materials and any needed adjuvants Sedgehammer 75WG (halosulfuron) Sulfentrazone.2G (sulfentrazone.2% active) 1 oz per acre (.47 lb ai) 2 oz per acre (.94 lb ai) 4 oz per acre (.188 lb ai).125 lb ai/acre.25 lb ai/acre.5 lb ai/acre V WG.5 lb ai/acre 1. lb ai/acre 2. lb ai/acre Untreated Reports: Reports must include: Results summary (no more than one page) Summary table with appropriate statistical analyses Experimental design and materials and methods Appendices: raw data and recordkeeping information as listed above If pictures were taken, please include them. Always use.25% v/v of a non ionic surfactant. If severe phyto symptoms do not occur and where feasible apply a second application 4-6 weeks later at identical rates. 2 applications on a 4 week interval 2 applications on a 4 week interval Kory Wheeler Kwheeler@gowanco.com FMC, Bobby Walls, , bobby_walls@fmc.com Valent, Joe Chamberlin, , jcham@valent.com A report submitted electronically 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. 12