IR-4 Ornamental Horticulture Program Trial Report

Transcription

1 Project Title: Evaluation of phytotoxicity of Sedgehammer (Halosulfuron) on Dwarf Periwinkle (Vinca minor Bowles ) IR4 PR#: 2517 Report date: November 2, 26 Authors: Heiner Lieth and Linda Dodge Department of Plant Sciences University of California, Davis Davis, CA Narrative Summary: Vinca minor Bowles plants growing in 1-gallon containers received two applications of Sedgehammer (halosulfuron) at 1 oz./acre (1X), 2 oz./acre (2X) or 4 oz./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 Sedgehammer. The trial was conducted over 8 weeks from March 3, 26 to May 22, 26. Although no phytotoxicity was attributable to Sedgehammer on Vinca, there was a significant growth suppression effect at all rates of application. This results in a delay in marketability of the plants, representing a significant added production cost. Thus Sedgehammer should not be used over the top on Vinca. 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: The Vinca minor Bowles liners received for the experiment had some chlorotic foliage resulting in initial phytotoxicity ratings of 2. Up until week 8 there were no significant differences in how the phytotoxicity index changed in the Sedgehammer-treated plants versus the control plants (Tables 1 and 3, Figure 1). At week 8 the measured levels were significantly different, but the difference was less than 1 in all treatments. The Vinca plants in all treatments grew with average treatment means increasing by 6.3 to 7.4 cm (Tables 2 and 3, Figures 1 and 3). Height increases were not significantly different among the treatments. The width increase was 21cm for the control plants. The width of the Sedgehammer-treated plants increased significantly less than the control, averaging increases ranging from 7.4 to 8.4 cm (Figure 2). This translated into volume index values for the control being 1126 while the mean volume index of the Sedgehammer-treated plants ranged from 31 to 41. Discussion: The level of phytotoxicity attributable to Sedgehammer was very small. Thus there is no evidence in this trial that this product causes phytotoxicity on Vinca. The lack of significant differences in plant height is expected since Vinca is a ground-cover. A growth retardation effect was evident in the width as well as volume index. All Sedgehammertreated plants showed the growth reduction effect with canopy volumes of the treated plants being 64%, 73%, and 63% smaller than the control plants. This growth reduction effect is so pronounced as to be unacceptable because this significantly delays marketability of the plants since groundcovers are sold at a particular plant canopy volume. Thus Sedgehammer should not be used over the top on Vinca. 2

3 Materials & Methods/Recordkeeping: Crop History Crop Cultivar/Variety: Date of Seeding: Date of Emergence: Dwarf Periwinkle (Vinca minor Bowles ) Date of Transplanting: Liners received from Monrovia 3/16/6, transplanted 3/27/6 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 3/28/6 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 Vinca minor Bowles were received from Monrovia Nursery, Visalia CA, on March 16, 26. The liners were transplanted to 1-gallon pots containing UC Mix on March 27, 26. The experiment ran from March 3, 26 to May 22, 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), 1 (1X), 2 (2X), or 4 (4X) oz./acre Sedgehammer 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 March 3, 26 and the second application 4 weeks later on April 27, 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 Sedgehammer Product(s) applied during experiment (including treatments, fertilizers, etc): Product Rate(s) Application Type Date of Application Crop Growth Stage Sedgehammer 1,2,4 Foliar spray 3/3/6 Actively growing oz./acre Sedgehammer 1,2,4 Foliar spray 4/27/6 Actively growing oz./acre Application Volume Data Collected: Data Collection. Phytotoxicity ratings were taken at week, 1, 2, 4, 5, 6 and 8, (March 27, 26; April 4, 11 and 25, 26; May 2, 9 and 22, 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 (March 27, 26) and week 8 (May 22, 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 Vinca minor Bowles treated with (Control), 1 (1X), 2 (2X) or 4 (4X) oz./acre Sedgehammer 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 Sedgehammer on Vinca Phytotoxicity Index Increase from beginning of trial until: Treatment 1 week (NA) 2 weeks no 4 weeks no X. ±. a -.22 ±.15 a -.11 ±.11 a 1X. ±. a. ±. a. ±. a 2X. ±. a. ±. a. ±. a 4X. ±. a -.22 ±.15 a -.11 ±.2 a Phytotoxicity Index increase from beginning of trial until: Treatment 5 week no 6 weeks no 8 weeks yes X -.11 ±.11 a -.11 ±.11 a. ±. b 1X. ±. a. ±. a.56 ±.18 a 2X. ±. a.11 ±.11 a.78 ±.22 a 4X.11 ±.11 a.11 ±.11 a.89 ±.2 a Table 2. Plant height, width and volume changes over 8 weeks for Vinca minor Bowles treated with (Control), 1 (1X), 2 (2X) or 4 (4X) oz./acre Sedgehammer 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 Sedgehammer on Vinca Increase by week 8 of: Treatment Height (cm) no Average Width yes Volume Index yes (cm) X 7.17 ±.69 a ± 1.34 a ± a 1X 7.39 ±.62 a 8.33 ± 1.8 b ± b 2X 6.28 ±.73 a 7.42 ± 1.77 b ± b 4X 7.44 ±.8 a 8.39 ± 1.3 b ± b 5

6 Raw Data: Table 3. Phytotoxicity and plant growth data collected for plants of Vinca minor Bowles treated with two applications of (Control), 1 (1X), 2 (2X), or 4 (4X) oz./acre Sedgehammer at weeks and 4 of an 8-week experiment. Phytotoxicity Report Form Vinca Sedgehammer 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 Sedgehammer on Vinca minor Bowles. 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 (%) 3/3/ /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/ /1/ /2/ /3/ /4/ /5/ /6/ /7/ /8/ /9/ /1/ /11/ /12/ /13/ /14/ /15/ /16/ /17/ /18/ /19/ /2/ /21/ /22/ /23/ /24/

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: Vinca -- Material: Sedgehammer Height (cm) Change (cm) Phytotoxicity Index Control 1X 2X 4X 35 Ctrl 1X 2X 4X Day of trial Day of trial Width (cm) Ctrl 1X 2X 4X Day of trial Change (cm) Volume Index 1 5 Ctrl 1X 2X 4X Day of trial Change Figure 1. Summary of results for Vinca minor Bowles treated with (Control), 1 (1X), 2 (2X) or 4 (4X) oz./acre Sedgehammer 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 CONTROL 1X Sedgehammer Figure 2. Reduced shoot growth and leaf chlorosis seen on Vinca minor Bowles 8 weeks after applications of 1oz./acre (1X) Sedgehammer at weeks and 4 (below). Control plant is above. 1

11 Block A Block B CONTROL 1X 2X 4X Block C Figure 3. Vinca minor Bowles 8 weeks after two applications of (Control), 1 (1X), 2 (2X), or 4 (4X) oz./acre Sedgehammer 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