O-zone Injury on Vegetables
Crystal Stewart-Courtens, Extension Vegetable Specialist
Eastern New York Commercial Horticulture

Common ozone symptoms are small, irregular, shaped spots that range in color from dark brown to black (stipple like) or light tan to white (fleck like). These spots are found only on the upper surface of the leaf. Very young and old leaves are less susceptible to ozone while newly mature leaves are the most susceptible. With severe damage, symptoms may extend to the lower leaf surface.
Insect feeding (red spider mite and some leafhoppers) produce flecks on the upper surface of leaves, much like ozone injury. Flecks from insect feeding are usually spread uniformly over the leaf surface while ozone flecks are concentrated in specific areas, usually most pronounced at the leaf tip and along the margins.
The most sensitive crops include: Bean, Broccoli, Muskmelon, Onion, Potato, Radish, Spinach, Sweet Corn, Tomato
Intermediate crops include: Carrot, Endive, Parsley, Parsnip, Turnip
Tolerant crops include: Beet, Cucumber, Lettuce

Upcoming Events
Good Agricultural Practices (GAPs) Food Safety Training
March 10, 2026
Newark, NY
Learn about food safety on the farm! This event hosted by the Cornell Vegetable Program, Cornell Lake Ontario Fruit Team, CCE Wayne County, and the NYS Department of Agriculture, will cover good agricultural practices (GAPs) to help reduce the risk of microbial contamination on the farm, keeping food and consumers safe.
Urban Ag Food Safety Webinar
March 11, 2026
Urban and small-scale producers are encouraged to join us for the Urban Ag Food Safety webinar, featuring speakers from Cornell Cooperative Extension and Cornell IPM. We will explore the 'why' behind food safety, providing a basic overview and diving into specific urban ag considerations including water, pest, rodent, and soil health challenges. We will touch on the regulation and marketing landscape, and share resources for learning more. Bring your questions!
2026 NYS Processing Vegetable Educational Meeting
March 16, 2026
Batavia, NY
Processing vegetable industry members who grow, manage, or support crop production for Farm Fresh First/Nortera Foods, Seneca Foods and/or Love Beets, are encouraged to sign-up for the 2026 NYS Processing Vegetable Industry Meeting! You will:
- Network at this in-person meeting.
- Learn the results of industry-funded research.
- Have a voice in Cornell research and Extension.
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2.0 Certified Crop Advisor (CCA) credits available.