Cornell Vegetable Program Enrollment

Program Areas

  • Food Safety
  • Variety Evaluation
  • Market Development
  • Pest Management
  • Cultural Practices

Enrollment Benefits

  • Telephone / Email Consultations
  • VegEdge Newsletter
  • Direct Mailings
  • Educational Meetings & Conferences
  • In-Field Educational Opportunities
  • On-Farm Research Trials

CVP Enrollment Form (PDF; 261KB)

Enrollee Login

Password:

Log In To Access:

  • Issues of VegEdge Newsletters

Not an Enrollee? Enroll Now!

Online Enrollment Form

Scouting Onions for Botrytis Leaf Blight Halo Lesions

Christy Hoepting, Extension Vegetable Specialist
Cornell Vegetable Program

May 21, 2024

Botrytis Leaf Blight (BLB) halo lesions are the tiny pin-prick to pin-head sized yellow necrotic spots surrounded by silvery halos (Fig. 1, lesions 5 and 6). The silvery halo is often blotchy in shape. 

Sometimes the necrotic spot is barely visible, which can make identification of such versions of these lesions tricky to identify (Fig. 1, lesions 2 and 3). 

When BLB halo lesions get old, the center becomes sunken and often splits, it is still yellowish in color and remnants of the silvery halo can usually still be seen (Fig. 1, lesion 9). 

Various nicks and dings caused by blowing debris or herbicide injury may be confused with BLB halo lesions (Fig. 2). 

BLB halo lesions can be distinguished by their ghostly appearance not penetrating the leaf surface. BLB halo lesions are most abundant on the outer leaves, usually on the underside of the leaf, and are distributed anywhere along the leaf. All of these lesions are counted when scouting to use for spray thresholds for BLB. Count the number of BLB halo lesions on the outer three leaves of 20-30 plants per field. Numbers can be highly variable among plants, so it is good to take a look at several plants. The number of lesions per leaf is the number of lesions per plant divided by 3. The spray threshold is 1.0 BLB halo lesion per leaf. 



BLB Lesions on an onion leaf

Figure 1. Ten Botrytis leaf blight (BLB) halo lesions on an onion leaf. Lesion No. 1, 4, 5, 6 and 7 have tiny yellow necrotic centers. In lesion No. 2, 3 and 10, the necrotic center is not visible. Lesion No. 8 does not have a distinct yellow center and blends into No. 7. Lesion No. 9 is an old lesion with a sunken center and silvery halo still visible. Photo: C. Hoepting, CCE Cornell Vegetable Program









BLB lesion among other nicksFigure 2. BLB halo lesion amongst other necrotic spots on onion leaf. Photo: C. Hoepting, CCE Cornell Vegetable Program


Scouting Onions for Botrytis Leaf Blight Halo Lesions (pdf; 234KB)

more crops
Asparagus

Asparagus

Beets

Beets

Broccoli

Broccoli

Brussels Sprouts

Brussels Sprouts

Cabbage

Cabbage

Carrots

Carrots

Cauliflower

Cauliflower

Cucumbers

Cucumbers

Dry Beans

Dry Beans

Eggplant

Eggplant

Ethnic Vegetables

Ethnic Vegetables

Garlic

Garlic

Horseradish

Horseradish

Kohlrabi

Kohlrabi

Leeks

Leeks

Lettuce / Leafy Greens

Lettuce / Leafy Greens

Melons

Melons

Mushrooms

Mushrooms

Onions

Onions

Parsnips

Parsnips

Peas

Peas

Peppers

Peppers

Potatoes

Potatoes

Pumpkins / Gourds

Pumpkins / Gourds

Radishes

Radishes

Rhubarb

Rhubarb

Rutabaga

Rutabaga

Snap Beans

Snap Beans

Squash - Summer

Squash - Summer

Squash- Winter

Squash- Winter

Sweet Corn

Sweet Corn

Sweet Potatoes

Sweet Potatoes

Tomatoes

Tomatoes

Turnips

Turnips

more crops

Upcoming Events

Genesee Valley Winter Produce Meeting

January 20, 2026
Farmersville, NY

Fresh market production meeting for small to mid-sized farms. Topics include: fundamentals of plant disease management, keeping yourself safe while spraying (organic & conventional), mushrooms, white mold management, selling at auction, and soil health.

View Genesee Valley Winter Produce Meeting Details

Chautauqua Region Winter Vegetable Meeting

Event Offers DEC Credits

January 30, 2026
Randolph, NY

Fresh market production meeting for small to mid-sized farms. Topics include: vegetable disease management, keeping yourself safe while spraying (organic & conventional), soil and water sampling, managing soil organic matter, grower panel, industry and programmatic updates.

DEC credits available: 1.0 in CORE plus 1.5 in 1a and 23.

View Chautauqua Region Winter Vegetable Meeting Details

Eden Area Winter Vegetable Meeting

Event Offers DEC Credits

February 4, 2026
North Collins, NY

Join us for a mix of industry updates, crop protection talks, pesticide safety programming, and fertility management discussions. This meeting is jointly hosted by the Cornell Vegetable Program and Timac Laing-Gro. 

1.25 DEC credits available in CORE plus 1.75 in 1a and 23.

View Eden Area Winter Vegetable Meeting Details

Announcements

We're Hiring! Vegetable Field Research Techs

Join our team! If you enjoy working outdoors and want to gain hands-on experience in plant agriculture and field research conducted on a diverse set of working vegetable farms, this position is an excellent opportunity for you! Working 2-3 years as a technician for the Cornell Vegetable Program (CVP) is proven foundation for students that are graduate school bound, as well as moving up within CVP/Cornell, especially in the Extension field. We are looking for someone with excellent work ethics, appreciation for agriculture, attention to detail and a can-do attitude.

Entry Level Positions:

Full-time, Albion, NY (Hoepting). 1-year appointment with potential for extension depending upon performance and funding. Excellent benefits. Working overtime (more than 40 hours/week), including evenings, is common from June through September. Emphasis on muck onion production, plant pathology, entomology and weed science. Learn more and apply!

Seasonal, Batavia, NY (Kikkert). June-August (39 hours/week) with possible extension depending on candidate availability. Assist with pest monitoring and data collection in a variety of crops including dry beans, snap beans, sweet corn, onions, potatoes and cole crops. Learn more!

Both positions:

  • Start June 1, 2026
  • Require reliable transportation for regular travel throughout CVP multi-county region
  • Involve working in vegetable crops that have been treated with pesticides
  • Involve some work on diverse vegetable crops, including organic
Application deadline: January 31, 2026

Cornell Crop and Pest Management Guidelines Paused

From Cornell IPM:

Highlighting its commitment to quality and long-term sustainability, Cornell Integrated Pest Management's Pesticide Safety Education Program has announced
a pause in production of the 2026 Cornell Crop and Pest Management Guidelines.

Cornell IPM Director Alejandro Calixto said this temporary measure is the result of a comprehensive reimagining process facilitated by Illume Projects of Ithaca, which included end-user interviews, internal surveys and sales data analytics.

"It became clear to us that we cannot continue producing the guidelines and fully restructure them at the same time," Calixto said. "By pausing production, we can dedicate all available resources and time to rebuilding the production process, ensuring that when we re-launch in 2027, the guidelines will reflect a modernized approach built around the grower and other user experience."

A series of annually updated reference manuals produced by Cornell IPM and the College of Agriculture and Life Sciences (CALS), the Cornell Crop and Pest Management Guidelines are widely used by farmers, agronomists, crop consultants and extension educators in New York and throughout the Northeast. They include information about current IPM recommendations, pesticide options, cultural practices, nutrient management, disease, insect and weed identification and resistance-management strategies.

Calixto and Pesticide Safety Education Program Lead Mike Helms will spearhead efforts to restructure the guideline process over the next 12 months, with a goal of launching a more streamlined, user-friendly version in 2027.

Limited copies of the 2025 guidelines remain available for purchase while supplies last through The Cornell Store. The 2026-2027 Greenhouse Guidelines will be available.

For more information contact Helms at mjh14@cornell.edu.


NEWSLETTER  |   CURRENT PROJECTS  |   IMPACT IN NY  |   SPONSORSHIP  |   RESOURCES  |   SITE MAP