White Rot Update
Crystal Stewart, Extension Vegetable Specialist
Eastern New York Commercial Horticulture
June 22, 2016
Earlier in June I sent a garlic sample to the diagnostic lab hoping that I was wrong. The sample was covered in small black sclerotia, the size of poppy seeds, and white fungal hyphae crept up the stem. The results, unfortunately, matched the field diagnosis: White Rot. Within a couple days additional calls came from up and down the Hudson Valley as well as one in Western NY with similar suspicions. These samples have also gone to the lab for verification, but it looks like the latest pest to move back into the state is this nasty fungus.
White Rot, Sclerotinia cepivorum, decimated the onion industry in New York in the 1930's before being eradicated through careful management. More recently, in 2003, it infected 10,000 acres of garlic in California, leading to the abandonment of some garlic fields and adoption of strict containment rules. White rot has been confirmed in Northeastern states over the last decade as well, with New York being one of the last to discover the disease.
The primary reason that White Rot is such a concern is because the sclerotia, or reproductive structures, can remain dormant in the soil for up to 40 years, attacking any allium crop planted into the soil under favorable conditions. This spring was ideal for infection due to the period of cool, moist weather we had. Optimal temperature for infection is 60-65 degrees F, but infection can occur anywhere from 50-75 degrees F.
Once garlic has white rot, it generally declines rapidly. Leaves will yellow and the plant will wilt, not unlike a severe fusarium infection. However, unlike with fusarium, white rot infected bulbs are covered in black sclerotia and white fungus. To add to the confusion, another disease CAN look similar. Botrytis also causes black sclerotia and white fungal growth. However, Botrytis sclerotia are quite large, often larger than a pencil eraser.
So, what do we do now? We're still working on long-term management strategies, but the most important steps to take now are vigilance when culling (look at the plants you are pulling for symptoms like you see in this article, and if they are present, call us to take a sample and have the disease verified) and, if you see anything suspicious, reduction of movement of inoculum. The main ways diseases get moved around are by dumping culls (compost, field edges, etc) and my moving soil on equipment. Throw away your culls, and wash equipment that may have come in contact with suspicious garlic or the soil it is growing in. Everything from cultivation equipment to harvest bins should be cleaned.
We will keep learning about this disease and will keep sending out information, particularly to help you make decisions about what to sell and buy. For now, remember that the west coast has learned to manage the disease, and we will too. -Crystal Stewart, ENYCHP
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Upcoming Events
Fresh Market Vegetable Grower Meeting
February 21, 2019
Th 1:00 - 3:30 PM
Newark, NY
This course will educate fresh market growers on current pest management, food safety, and marketing issues in fresh market crops. Specific topics covered include: managing the weed seedbank, Farm to School marketing opportunities, Late Blight updates, FSMA On-Farm Readiness Reviews, biopesticides and biostimulants and how they work, wash line equipment cleaning checklist, and a discussion of production problems throughout the 2018 growing season.Designing a Safe and Sanitizable Packing Line
March 6, 2019
W 9:00 AM - 12:00 PM
Branchport, NY
Join Robert Hadad, CVP vegetable specialist, to learn about how to design a produce packing line that fits your budget and maximizes efficiency and food safety. This workshop will cover what you need to take into account when designing your line, along with how you can modify an existing system to for increased sanitation and efficiency. Robert will also discuss how packing line and packing house design fits in with the new Food Safety Modernization Act requirements.Produce Safety Alliance Grower Training
March 11 - March 12, 2019
M 9:00 AM - 5:00 PM; T 9:00 AM - 3:00 PM
Binghamton, NY
Are you a farmer interested in produce safety? Are your markets asking for food safety plans or third party verification? Do you want to understand produce safety issues as they relate to the Food Safety Modernization Act (FSMA) Food Safety Rule, third party audits and Good Agricultural Practices (GAPs)? Participation in this training, hosted by CCE Broome County, will give you the tools to create an on-farm food safety plan and complete one of the requirements of either FSMA OR the New York State Grown and Certified branding program. We will also discuss potential funding streams to make infrastructure upgrades to your farm related to food safety!Announcements
Cornell Commercial Vegetable Guidelines Available
The 2019 Cornell Integrated Crop and Pest Management Guidelines for Commercial Vegetable Production are now available!Written by Cornell University specialists, this publication is designed to offer producers, seed and chemical dealers, and crop consultants practical information on growing and managing vegetable crops in New York State. Topics include general culture, nutrient management, transplant production, postharvest handling, organic production, and managing common vegetable crop pest concerns. A preview of the Vegetable Guidelines can be seen online.
Highlighted changes in the 2019 Vegetable Guidelines include:
- Updated pesticide options for economically important vegetable crop pests.
- New pests: beet armyworm in beets; cabbage looper and tarnished plant bug in lettuce and endive; allium leafminer in onions; and Cladosporium, Cercospora, and Stemphylium leaf spots in spinach.
Empire State Producers EXPO Proceedings
Proceedings from the Empire State Producers EXPO conference from 2011-2019 are available online.2018 Cornell Vegetable Program Year in Review
2018 is behind us but we hope that our team's efforts to enhance New York vegetable production continues well beyond! This year, our Specialists gave presentations at 119 events, sharing our knowledge with 3,535 people.We continue to conduct on-farm research to help answer the questions of our growers. The Cornell Vegetable Program managed 50 research grants and projects in 2018. We extend our gratitude to the 65 farms and organizations that offered us land, labor, and supplies to support our trials! We also want to thank those farmers that gave generous financial contributions to support our work as well.
We cannot forget to thank the 13 Cooperative Extension Associations that partnered with us this year too. We're excited to be adding Steuben County to our list of participating counties in 2019!
Our 2018 Year in Review brochure highlights our research and educational projects.