IR-4 Ornamental Horticulture Program Research Report Form

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1 Project Title: IR-4 Ornamental Horticulture Program Evaluation of phytotoxicity for Sulfentrazone 0.2G on Easter Lily (Lilium longiflorum Nellie White ) Protocol#: Report date: June 12, 2007 Authors: Heiner Lieth and Linda Dodge Department of Plant Sciences University of California Davis, CA Narrative Summary (Results/Discussion) Bulbs of Lilium longiflorum Nellie White (size 8-9) were planted in 6-inch containers and received one application of Sulfentrazone 0.2G at lb/acre (1X), 0.25 lb/acre (2X) or 0.5 lb/acre (4X) rates 5 days after planting. The plants in the Control group received no Sulfentrazone 0.2G. The bulbs were pot-cooled for 3 weeks and then grown out in a greenhouse for 11 weeks. The trial was conducted over a total of 15 weeks from November 30, 2006 to March 14, Results The Sulfentrazone application to the top of the growing medium in pots where Easter Lily bulbs had been planted earlier, resulted in phytotoxicity index levels of zero from week 8 (at which point the plants were emerged from the substrate) to week 11 (prior to onset of flowering) (Tables 1 and 3, Figure 1). By week 13, however, substantial problems appeared in the form of serious phytotoxicity on the upper leaves and flowers. The upper leaves were distorted in shape and exhibited patches of necrosis while the flower buds were reduced in size and distorted on plants treated with the 2X and 4X rates (Figure 4a). Roots of representative plants were examined at week 15 and the 2X and 4X treatments exhibited reduced basal root growth (Figure 4b). At the same time, no phytotoxicity was apparent in the control plants, indicating that the effect was due to the herbicide. Plants which grew through the growing medium to which the herbicide had been applied had phytotoxicity levels on week 15 which increased with increasing concentration of herbicide application: from a mean phytotoxicity index level of 2.3 for the 1X treatment to 6.7 for the 4X treatment (Tables 1 and 3, Figures 1, 3a and 3b). There was also a substantial growth retardation effect due to Sulfentrazone with plants being considerably shorter and narrower (Tables 1 and 3, Figures 2, 3a and 3b). Early in the production of the lilies, this effect is not dramatic so that statistically there are no significant differences between any of the treated and the control plants up until week 15. By week 15 plants in the 4X treatments were significantly shorter and narrower than the control. For the 1X treatment, however, there was no significant difference in height, width or canopy volume at week 15. The ultimate canopy volume (at the time when the plants were flowering and ready for sale) was smaller in the 2X and 4X treatments, but not the 1X treatment. 1

2 Discussion It should be noted that the emerging main stem had to at some point pass through the substrate at the top of the growing medium to which the herbicide had been applied. While it is curious that very little damage was noted to the majority of leaves, most of which were forming as the stem emerged, substantial damage resulted to the forming reproductive tissue and upper leaves. It should be noted that height reduction on Easter lily is generally a desirable thing as growers typically apply a considerable amount of growth retardant to keep the plants compact. In this study no growth retardants were applied, so that the plants which had received the herbicide treatment had more desirable plant heights than the control. However, the width was also significantly reduced and this is not desirable; growers are not interested in having the width change since a narrower plant has a poorer appearance. This effect was, however, only an issue in the 2X and 4X treatments; so if growers adhere to the proposed label rate, then the plants should be free from significant deleterious growth effects. The premise underlying this study was that Easter lily forcers would be able to benefit from an herbicide that can be applied to pots in which the bulbs have been planted and where the pots are set in a cool location while the plants are waiting to emerge. Some growers cool their potted Easter lily plants outdoors in the late fall where weed seeds can get into the pots. These then require hand-weeding as the plants are forced in the greenhouse. Sulfentrazone is not a suitable herbicide for this purpose since it does cause damage to the leaves and flowers which becomes apparent just prior to shipping for Easter. Although the average phytotoxicity rating for the 1X treatment was 2.3 making the plants still potentially salable, the location of the damage on leaves so close to the flower buds makes this application rate too risky. Thus we conclude that Sulfentrazone should not be used on Easter lilies being forced for Easter sales. 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 Priyasheila Singh (plant culture, data collection). The materials being tested were supplied by the manufacturer/distributor. Bulbs were provided by the Easter Lily Research Foundation, Brookings OR. 2

3 Results Table Table 1. Phytotoxicity and growth changes over 15 weeks for Lilium longiflorum Nellie White treated with 0 (Control), (1X), 0.25 (2X) or 0.5 (4X) lb/acre Sulfentrazone 0.2G at week 0. Differing letters a, b, c designate significant differences among the four means; "Yes" and "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 ± SE (n=9) Phytotoxicity Effect of Sulfentrazone on Lilium Phytotoxicity Index Increase from beginning of trial until: Treatment 8 week (NA) 10 weeks (NA) 11 weeks no 0X 0.00 ± 0.00 a 0.00 ± 0.00 a 0.00 ± 0.00 b 1X 0.00 ± 0.00 a 0.00 ± 0.00 a 0.00 ± 0.00 b 2X 0.00 ± 0.00 a 0.00 ± 0.00 a 0.33 ± 0.33 ab 4X 0.00 ± 0.00 a 0.00 ± 0.00 a 1.22 ± 0.62 a Phytotoxicity Index increase from beginning of trial until: Treatment 13 weeks yes 15 weeks yes 0X 0.00 ± 0.00 d 0.00 ± 0.00 d 1X 1.11 ± 0.42 c 2.33 ± 0.69 c 2X 3.22 ± 0.22 b 5.11 ± 0.31 b 4X 4.56 ± 0.34 a 6.67 ± 0.17 a Growth Effect of Sulfentrazone on Lilium Increase by week 8 of: Treatment Height (cm) no Average Width no Volume Index no (cm) 0X 7.94 ± 0.41 a 8.44 ± 0.49 a ± a 1X 7.61 ± 0.73 a 8.25 ± 0.76 a ± a 2X 8.17 ± 0.49 a 8.78 ± 0.76 a ± a 4X 7.50 ± 0.51 a 7.92 ± 0.65 a ± a Increase by week 10 of: Treatment Height (cm) no Average Width no Volume Index no (cm) 0X ± 1.25 a ± 0.77 a ± a 1X ± 1.55 a ± 1.53 a ± a 2X ± 1.08 a ± 0.94 a ± a 4X ± 1.34 a ± 1.31 a ± a Increase by week 11 of: Treatment Height (cm) no Average Width no Volume Index no (cm) 0X ± 1.56 a ± 0.58 a ± a 1X ± 1.63 a ± 1.29 a ± a 2X ± 1.63 a ± 1.11 a ± a 4X ± 1.75 a ± 1.18 a ± a Increase by week 13 of: Treatment Height (cm) yes Average Width no Volume Index yes (cm) 0X ± 2.20 a ± 0.68 a ± a 1X ± 2.76 a ± 0.99 a ± a 2X ± 2.20 b ± 0.65 a ± b 4X ± 2.06 b ± 1.00 a ± b Increase by week 15 of: Treatment Height (cm) yes Average Width yes Volume Index yes (cm) 0X ± X ± X ± X 1X ± X ± X ± X 2X ± X ± X ± X 4X ± X ± X ± X 3

4 Species: Lilium -- Material: Sulfentrazone Phytotoxicity Index Treatment Pot- Cooling Control 1X 2X 4X Moved pots into greenhouse Day of trial Figure 1. Phytotoxicity index ratings over 15 weeks for Lilium longiflorum Nellie White treated with 0 (Control), (1X), 0.25 (2X) or 0.5 (4X) lb/acre Sulfentrazone 0.2G at week 0. SE bars shown. (n = 9) 4

5 Species: Lilium -- Material: Sulfentrazone IR-4 Ornamental Horticulture Program 50 Height (cm) Treatment Moved pots into greenhouse Day of trial 30 Width (cm) Day of trial Volume Index Day of trial Figure 2. Plant height, width and volume over 15 weeks for Lilium longiflorum Nellie White treated with 0 (Control), (1X), 0.25 (2X) or 0.5 (4X) lb/acre Sulfentrazone 0.2G at week 0. SE bars shown. (n = 9) (See Figure 1 for treatement legend.) 5

6 Block A Block B CONTROL 1X 2X 4X Block C Figure 3a. Representative plants of Lilium longiflorum Nellie White 15 weeks after 1 application of 0 (Control), (1X), 0.25 (2X) or 0.5 (4X) lb/acre Sulfentrazone 0.2G at week 0. 6

7 Block A Block B CONTROL 1X 2X 4X Block C Figure 3b. Representative plants of Lilium longiflorum Nellie White 16 weeks after 1 application of 0 (Control), (1X), 0.25 (2X) or 0.5 (4X) lb/acre Sulfentrazone 0.2G at week 0. 7

8 1X Sulfentrazone 2X Sulfentrazone 4X Sulfentrazone Figure 4a. Phytotoxicity symptoms seen on Lilium longiflorum Nellie White 15 weeks after one application of lb/acre (1X) (left), 0.25 lb/acre (2X) (middle) and 0.5 lb/acre (4X) (right) Sulfentrazone 0.2G at week 0. The upper leaves are distorted and necrotic for all rates and the buds are distorted and reduced for the 2X and 4X rates. CONTROL 2X Sulfentrazone 4X Sulfentrazone Figure 4b. Representative plants of Lilium longiflorum Nellie White 15 weeks after one application of 0 (Control), 0.25 (2X) or 0.5 (4X) lb/acre Sulfentrazone 0.2G at week 0 (left to right). The container medium has been washed from the roots. Plants treated with Sulfentrazone show reduced growth of basal roots compared to the control plant at left. 8

9 Materials & Methods/Recordkeeping Crop History Crop Cultivar/Variety: Date of Seeding: Date of Emergence: IR-4 Ornamental Horticulture Program Easter Lily (Lilium longiflorum Nellie White ) Date of Transplanting: Bulbs received from ELRF 10/17/06, planted 11/30/06 Potting Mix: Pot size & spacing: Row spacing: UC Mix: 1/3 sand, 1/3 peat, 1/3 bark (by volume) 6-inch pots spaced on 12-inch centers Product(s) applied prior to start of experiment: Product Rate Application Type Osmocote Date of Application Crop Growth Stage 1 tsp./pot Topdress 12/4/06 4 days after planting bulbs Application Volume NA Experiment Information Experimental Design: Number of Reps: Randomized complete block 9 (3 blocks x 3 reps per block) Application Equipment: Manual spray bottles for Sulfentrazone 0.2G Product(s) applied during experiment (including treatments, fertilizers, etc): Product Rate(s) Application Type Date of Application Crop Growth Stage Application Volume Sulfentrazone 0.2G 0.125, 0.25, 0.5 lb/acre Foliar spray OTT 12/5/06 5 days after planting bulbs Materials & Methods: Plant Material and Culture. Bulbs of Lilium longiflorum Nellie White (size 8-9) were received from the Easter Lily Research Foundation (ELRF), Brookings OR, on October 17, The bulbs were case-cooled at F for 7 weeks. The bulbs were planted in 6-inch pots containing UC Mix on November 30, The potted bulbs were treated with Sulfentrazone 0.2G on December 5, 2006 and then cooled at F for 3 more weeks. The potted bulbs were transferred to a greenhouse at 75 /65 F on December 28, 2006 and grown on for 11 weeks until March 14, 2007 (Figure 5). The plants were irrigated as needed during the 15-week experiment by hand with tap water for the first 4 weeks and then daily using an automatic drip system that delivered a half-strength Hoagland s solution at 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 0 (Control), lb/acre (1X), 0.25 lb/acre (2X) or 0.5 lb/acre (4X) Sulfentrazone 0.2G with 9 replicates per treatment. These dosages were prescribed in IR4 9

10 Ornamental Protocol (Appendix A). The plants received the foliar spray application on December 5, Data Collection. Phytotoxicity ratings were taken at week 8, 10, 11, 13 and 15 (January 22, 2007, February 5, 12 and 26, 2007 and March 14, 2007). Visual phytotoxicity evaluations were based on a numerical rating scale ranging from 0 (no injury) to 10 (complete kill) (Table 2). Table 2. 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 Plant height and width were measured at week 8, 10, 11, 13 and 15 (January 22, 2007, February 5, 12 and 26, 2007 and March 14, 2007). 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 scaleindependent, 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. 10

11 Greenhouse Air Temperature (F) /19/ /29/2006 1/8/2007 1/18/2007 1/28/2007 2/7/2007 2/17/2007 2/27/2007 3/9/2007 3/19/2007 3/29/2007 Figure 5. Greenhouse temperatures during the experiment to determine phytotoxicity of Sulfentrazone 0.2G on Lilium longiflorum Nellie White. 11

12 Raw Data Table 3. Phytotoxicity and plant growth data collected for plants of Lilium longiflorum Nellie White treated with one application of 0 (Control), (1X), 0.25 (2X) or 0.5 (4X) lb/acre Sulfentrazone 0.2G at week 0 of a 15-week experiment. (Missing data for week 15 is due to theft of plants.) Phytotoxicity Report Form Lilium Sulfentrazone IR4 Trial Phytotoxicity at week Plant Size at week 8 Plant Size at week 15 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

13 APPENDIX A Phytotoxicity to ornamental horticulture plants from tools to manage broadleaf weeds and sedges. Ornamental Protocol Number: Objective: Determine phytotoxicity of Manage (halosulfuron), Sulfentrazone 0.2G, and V 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 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. 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 0.2G (sulfentrazone 0.2% active) 1 oz per acre (0.047 lb ai) 2 oz per acre (0.094 lb ai) 4 oz per acre (0.188 lb ai) lb ai/acre 0.25 lb ai/acre 0.5 lb ai/acre V WG 0.5 lb ai/acre 1.0 lb ai/acre 2.0 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 0.25% 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, 308 Aston Forest Lane, Crownsville, MD 21032, Phone & FAX#: , evvea@comcast.net. 13