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A NOT SO NOBLE ROT
Western WA Wine Grape Growers Workshop 30 March 2011 Mt. Vernon Disease Management: Botrytis in Wet/Humid Climates
Dr. Michelle M. Moyer Asst. Prof.- Viticulture Extension WSU-IAREC Email: [email protected]
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OVERVIEW BIOLOGY-DISEASE CYCLE
• Botrytis Biology – Disease development/cycle – Research (past and present) • Disease Management • Cultural Practices • Traditional options • Organic options
Nicholas, et al. 1994
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BIOLOGY-THE BASICS POINTS OF INFECTION
• Temperature preference: 53- 86°F (optimum 64-70°F ) • Needs 1.5 hrs of “leaf wetness” – (likes damp conditions) Stamens • A weak pathogen Rachises – Grows everywhere on dead or dying tissue – Infects through injuries/ openings – PM can enhance BR Berry Caps Aborted Berries
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POINTS OF INFECTION, CON’T BIOLOGY-VEGETATIVE TISSUE ATTACK
• Botrytis can occasionally cause flower, leaf and shoot blight – Generally in VERY wet years Bunch debris – On excessively vigorous vines (control nitrogen levels)
“Mechanical” damage
Wounds
Photos courtesy of www.msu.edu
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BIOLOGY-THE WITHIN CLUSTER SPREAD BIOLOGY-THE WITHIN CLUSTER SPREAD
• Spreads via touching berries • Longer hang-time = more time for increased infection – Use judgment for harvest dates – What are the weather conditions going to be? • Cannot eradicate once established, can only slow the spread
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DISEASE MANAGEMENT- CULTURAL PRACTICES
• Drip vs. mist vs. overhead irrigation • Canopy manipulation can help! DISEASE MANAGEMENT: • Reduce humidity, reduce drying time • Ways to do this: BOTRYTIS BUNCH ROT – Managing canopy vigor – Shoot thinning (canopy density) – Leaf pulling- timing and amounts Open Canopy= Better spray deposition + air circulation + light penetration
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DISEASE MANAGEMENT- CULTURAL PRACTICES DISEASE MANAGEMENT-LEAF PULLING
• Leaf Pulling – Directed at the fruiting zone – Previous practice was from set – veraison – Current research focuses on prebloom-set
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DISEASE MANAGEMENT- CULTURAL PRACTICES DISEASE MANAGEMENT-LEAF PULLING
• Leaf Pulling – Directed at the fruiting zone – Previous practice was from set – veraison – Current research focuses on prebloom-set • CAUTIONS – Leaf pulling late can cause sunburn – Costly – Too much leaf removal too early can reduce set
Photo courtesy of Dr. Craig Austin
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DISEASE MANAGEMENT- CULTURAL PRACTICES DISEASE MANAGEMENT- SUSCEPTIBILITY
Shoot thinning, positioning, • Judging vine susceptibility for and general canopy Botrytis bunch rot is not easy. management are also crucial • Usually based on: – Cluster architecture and compactness – Tendency to swell and split – Powdery mildew susceptibility If you can’t see the fruit zone, neither can a – Insect and animal feeding sprayer... preference
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DISEASE MANAGEMENT- SUSCEPTIBILITY DISEASE MANAGEMENT- MONITORING INFECTIONS
Moderately Low Susceptible • Sample green and coloring clusters (~15-30) Susceptible Susceptibility Chardonnay, Semillion*, Cabernet • Place in a wet plastic bag; seal Chenin blanc, Sangiovese, sauvignon*, Vignoles, Vidal blanc Merlot, Cabernet • Freeze/incubate at room temperature Grenache, Pinot franc* Question: noir, Pinot gris, • Clusters with Botrytis infections will show Riesling, Sauvignon blanc, Traminer, What should you sporulation in 1-3 days Barbera, Grenache, The problem with consider when Petite syrah, generalizations... – Incidence and severity will vary Zinfandel, Seyval selecting clones? blanc, Baco noir, – If more than 1/3 of bunches in sprayed* Semillion*, Cabernet vineyard are sporulating, contact sauvignon*, extension agent Cabernet franc*
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DISEASE MANAGEMENT- FUNGICIDE CHOICES DISEASE MANAGEMENT- DUAL FUNGICIDES
Trade Resist. Class Common Name Type Name Risk Trade PM Rate Bunch Rot Class Common Name Carboximide Captan Captan Low Protectant Name (oz/A) Rate (oz/A) 50WP Strobilurin/ Pyraclostrobin/ Anilinopyrimidine Vangard Cyprodinil High Protectant/postinfec. Pristine 1.5-2.0 3.0 Anilinopyrimidine Scala Pyrimethanil High Protectant/postinfec. carboxin boscalid 8.0- Dicarboximide Rovral Iprodione High Protectant/postinfect/ Strobilurin Flint Trifloxystrobin 12.5 antispor. 10.5 Strobilurin/ carboxin Pristine Pyraclostrobin/ High protectant/antispor. Azole/ boscalid Inspire Difenoconazole/ Anilinopyrimidine 16-20 Strobilurin Flint Trifloxystrobin High Protectant; higher rate Super cyprodinil than for PM Carboxin Endura Boscalid High Protectant/postinfec; higher rate than PM Hydroxyanalide Elevate Fenhexamid Mod. Protectant; some PM 50WDG control, limit sprays USE CAUTION- RESISTANCE AND RATES MATTER Sterol inhibitor Elite 45 DF Tebuxonazole Mod Post-infect; antisporul. Courtesy of Dr. Wayne Wilcox, Cornell University-NYSAES
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DISEASE MANAGEMENT: ORGANIC OPTIONS
Trade Common Resist. Class Type GENERALIZED SPRAY PROGRAM: Name Name Risk Protectant/postinfec. Copper Copper Low (slow drying conditions hydroxide increase injury risk) BOTRYTIS BUNCH ROT Serenade Bascillus subtilis Low ? Biologicals ?? Sonata Bacillus pumilis Low ?
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DISEASE MANAGEMENT- GENERAL SPRAY PROGRAM DISEASE MANAGEMENT- GENERAL SPRAY PROGRAM
• Latent Infections: • Fruit Rot – Infections here are – Latent infections not expressed until expressed veraison – New infections on ripening clusters – Infects through – Infections spread stamens/scars quickly within cluster – Bloom spray at – Monitor weather cluster zone – Spray at first signs (do – Monitor weather not wait!) conditions
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REVIEW AND CONCLUSIONS WEBSITES
• Biology and history • Washington State University • Implications in viticulture and enology – www.wine.wsu.edu/research-extension/ • Oregon State University • Managing outbreaks in cool, wet climates – www.ipmnet.org – Focus of spray programs • Cornell University – Viticultural practices – www.nysaes.cornell.edu • Ontario Ministry of Ag. – www.omafra.gov.on.ca/ • BC Ministry of Ag.* – www.agf.gov.bc.ca
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QUESTIONS?
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