White Rot and Black Rot Biology and Management
Mike Basedow, Tree Fruit Specialist
Eastern New York Commercial Horticulture
The white rot fungus, Botryosphaeria dothidea, often referred to as "Bot rot" or Botryosphaeria rot, can be a distinct canker on twigs, limbs, and trunks. The fungus produces two types of fruit rot, but leaf infections do not occur. Drought stress and winter injury have been associated with an increase in infection and canker expansion. This is a relatively weak fungal pathogen, and is only problematic when a tree is stressed, such as due to drought, winter injury, insect damage, or fire blight.
The black rot and frogeye leaf spot fungus, Botryosphaeria obtusa, attacks fruit, leaves, and bark of apple trees and other pomaceous plants.
White Rot and Black Rot Biology and Management (pdf; 287KB)
Apples
Apricots
Asparagus
Beets
Blueberries
Broccoli
Brussels Sprouts
Cabbage
Carrots
Cauliflower
Cherries
Cucumbers
Dry Beans
Eggplant
Ethnic Vegetables
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Grapes
Horseradish
Kohlrabi
Leeks
Lettuce / Leafy Greens
Melons
Nectarines
Onions
Parsnips
Peaches
Pears
Peas
Peppers
Plums
Potatoes
Pumpkins / Gourds
Radishes
Raspberries / Blackberries
Rhubarb
Rutabaga
Snap Beans
Squash - Summer
Squash- Winter
Strawberries
Sweet Corn
Sweet Potatoes
Tomatoes
Turnips
Upcoming Events
Rulfs Orchard Vegetable and Berry Field Meeting
August 4, 2026
Peru, NY
Join CCE vegetable specialists Elisabeth Hodgdon and Chuck Bornt for a vegetable and berry field meeting at Rulfs Orchard, in Peru, NY. We'll tour the farm's fields and talk about integrated pest management of sweet corn and cucurbit crops. Then, we'll view a drone demonstration and discuss new technologies for pesticide application and spotted wing drosophila management in berries. Light refreshments will be provided. A rain date will be announced if adverse weather is predicted.
Field Day at Philia Farm
August 6, 2026
Johnstown, NY
Visit organic seed production trials and tour the farm to see small-scale production systems at work, including tarping, cover cropping, and the use of assorted mulches and covers to modify the growing environment.
Capital Region Orchard Twilight Meeting
August 11, 2026
Rexford, NY
Join the ENYCHP and Cornell scientists on August 11 for the Capital Region Orchard Twilight meeting in Saratoga! We will be touring Bowman Orchards and reviewing seasonal recommendations for pests and diseases for apples, plums, and berries, as well discussing crop insurance.
NYSDEC Pesticide Applicator Recertification Credits: 1.25 in categories 22, 1A, & 10. Refreshments will be provided.
Free to attend, however we do ask that you register ahead so we know how many people to expect.