Phytotoxicity and Efficacy of Rhapsody (Bacillus subtilis) for Control of Botrytis cinerea on Lily (Lilium Star Gazer and Show Winner )

Transcription

1 Phytotoxicity and Efficacy of Rhapsody (Bacillus subtilis) for Control of Botrytis cinerea on Lily (Lilium Star Gazer and Show Winner ) By Heiner Lieth, Director Linda Dodge Shannon Still Ron Lane Project: USDA Interregional Research Project #4 Project Number 20287A September 18, 2003 Acknowledgements: Donors/Supporters: CDFA Minor Crops Research Grant, Project 2: Enhancement of the Western Region IR-4 Program to Address California Needs Nurserymen s Exchange, Half Moon Bay CA UC Davis Environmental Horticulture IR4 Center Department of Environmental Horticulture University of California One Shields Ave. Davis, CA

2 1. INVESTIGATOR (Name, Address, Phone#): Dr. Heiner Lieth Department of Environmental Horticulture University of California One Shields Ave. Davis, CA Ph FAX IR-4 ORNAMENTAL DATA REPORTING FORM (Please type or print) LOCATION OF TRIAL: Dept. of Env. Hort., University of California, Davis TRIAL TYPE:(check one) cold storage, container plants 2. PESTICIDE: COMMON NAME: Bacillus subtilis FORMULATION: aqueous suspension (1.34% ai) BATCH NO.: PRODUCT: Rhapsody EPA REG. NO XX MFG: Agraquest, Davis, CA 3. USE INFORMATION: COMMON NAME SCIENTIFIC NAME PLANT: Hybrid Oriental Lily, cvs Star Gazer and Show Winner Lilium PEST (S): Botrytis SOIL TYPE OR TYPE OF POTTING MIX: peat-based potting mix from grower % SAND % SILT % CLAY % OM % ph SEEDING DATE EMERGENCE DATE TRANSPLANTING DATE PLANT OR POT SPACING pot-to-pot ROW SPACING POT SIZE 6 inch (15 cm) PLOT SIZE 20 sq. feet EXPERIMENTAL DESIGN completely randomized NO.OF REPS 6 for each cv 4. APPLICATION PARAMETERS: TYPE OF APPLICATION: foliar NO. OF APPLICATIONS 4 APPLICATION TYPE manual spray bottle NOZZLE TYPE/SIZE NOZZLE PRESSURE DELIVERY RATE CALIBRATION DATE (S) 5. APPLICATION SUMMARY: APPL.DATE RATES (a.i./a)* GROWTH STAGE , 0.134, 0.268, ppm Puffy bud , 0.134, 0.268, ppm 1-2 open flowers per plant , 0.134, 0.268, ppm 3 or more open flowers per plant , 0.134, 0.268, ppm 3 or more open flowers per plant *Be sure to provide units 2

3 IR-4 ORNAMENTAL DATA REPORTING FORM (Please type or print) 6. RAINFALL/IRRIGATION RECORDS: Plants were watered three times with half-strength Hoagland s solution during 35-day cold storage period. INCLUDE RAINFALL/IRRIGATION INFORMATION (printouts, IR-4 forms, etc.) 7. OTHER PESTICIDES, FERTILIZER, LIME AND ADJUVANTS USED: Triton B-1956 was used as an adjuvant with each application of Rhapsody. 8. NARRATIVE SUMMARY OF METHODS AND RESULTS: (Use more pages if needed) Materials and Methods Plant Material and Culture. The plants for this experiment were obtained from Nurserymen s Exchange in Half Moon Bay, CA. Twenty-five plants each of two cultivars of Hybrid Oriental lilies, Star Gazer and Show Winner, in six-inch pots at commercial stage (puffy buds) were transported from the grower to UC Davis on Upon arrival at UC Davis, all plants were placed in a growth chamber with a constant temperature of 45 F (7 C). The chamber was lighted 12 hours per day with incandescent lights. The plants were watered three times with half-strength Hoagland s solution during the 35-day cold storage period. Experimental Procedure. Twenty-four plants of each lily cultivar were chosen and randomly assigned to four treatment groups. For each of four preventative applications of Rhapsody over the 35-day treatment period the plants were removed from the growth chamber and placed in treatment groups in a greenhouse at 75 F (24 C). The plants were sprayed with 0, 0.134, or ppm Rhapsody using Triton B-1956 as an adjuvant. The material was allowed to dry and then the plants were returned to the growth chamber in completely randomized arrangements separate for each cultivar (Figures 1 and 2). Later the same day or the next day the plants were challenged with Botrytis by spraying the leaves with a spore suspension. The first suspension used contained 10,000 Botrytis spores per ml and the subsequent three challenges were done with Botrytis spores at a concentration of 100,000 spores per ml. The plants were treated and challenged weekly for four weeks, inspected for foliar symptoms of Botrytis infection two or three times per week and finally removed from the growth chamber 35 days (5 weeks) after the beginning of the experiment. The plants were separated into treatment groups and rated for disease symptoms (Figure 3). Statistical Analysis. Not applicable (see below) Results Phytotoxicity. Rhapsody had no phytotoxic effects on leaves or flowers of Star Gazer and Show Winner Hybrid Oriental lilies (Appendix A). Because all phytotoxicity measurements were zero, no statistical analysis was needed to state conclusively that there was no phytotoxicity. No leaf yellowing was observed within the normal storage time for potted Oriental lilies. Leaf yellowing did occur by day 30 but was attributed to the abnormally long cold storage period (Figures 2 and 3). Efficacy. No symptoms of Botrytis infection were seen on any of the plants in the experiment, including the control plants (Appendix B). Judgment as to the efficacy of Rhapsody as a preventative treatment for Botrytis infection of Hybrid Oriental lily leaves or flowers cannot, therefore, be made. Discussion Although this experiment completely conformed to the IR4 protocol, subsequent discussion with the registrant and project request author revealed that the plant material of interest was field-dug lily bulbs rather than flowering plants. 3

4 9. 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 Dr. Heiner Lieth PRINCIPAL INVESTIGATOR DATE 4

5 Figure 1. Star Gazer (left) and Show Winner (right) Hybrid Oriental lilies on Day 3 of the cold storage experiment at 45 F (7 C), one day after the first application of Rhapsody and the first challenge with Botrytis. Figure 2. Star Gazer (left) and Show Winner (right) Hybrid Oriental lilies on Day 30 of the experiment, seven days after the fourth application of Rhapsody and the fourth challenge with Botrytis. Yellowing of the lower leaves was attributed to the abnormally long cold storage period at 45 F (7 C). 5

6 Figure 3. Hybrid Oriental lily plants (cultivars Star Gazer and Show Winner ) after 35 days (5 weeks) in cold storage at 45 F (7 C). The plants were treated weekly for four weeks with 0, 0.134, or ppm Rhapsody and subsequently challenged four times with Botrytis by spraying with spore suspensions at concentrations of 10,000 to 100,000 spores per ml. 6

7 APPENDIX A: PHYTOTOXICITY REPORT FORM TREATMENT RATE* ai/ PHYTO REP. PHYTO RATE # PHYTO RATE # PHYTO RATE # PHYTO RATE # CONTROL CONTROL CONTROL CONTROL CONTROL 0 MEAN X ppm X ppm X ppm X ppm X ppm MEAN X ppm X ppm X ppm X ppm X ppm MEAN X ppm X ppm X ppm X ppm X ppm MEAN NOTE: DEFINE MEASUREMENT OF PHYTOTOXICITY, OR INDEX OF INJURY (0=NO INJURY, 10=COMPLETE KILL) *Be sure to provide units 7

8 APPENDIX B: EFFICACY REPORT FORM TREATMENT RATE* ai/ REP. PEST DATE PEST DATE PEST DATE PEST DATE CONTROL** CONTROL CONTROL CONTROL CONTROL 0 MEAN X ppm X ppm X ppm X ppm X ppm MEAN X ppm X ppm X ppm X ppm X ppm MEAN X ppm X ppm X ppm X ppm X ppm MEAN NOTE: DEFINE MEASUREMENT OF PEST POPULATION AND EFFICACY SCALE (0=NO CONTROL, 10=COMPLETE CONTROL) Data measured were numbers of Botrytis-induced foliar lesions per plant **In herbicide trials report for both weedy check and weed-free check. *Be sure to provide units 07/94 8