Fruit rot is caused by a fungus. The disease is characterized by a watery, soft rot of infected fruit, either in the field or in storage. In moist conditions, the diseased fruit develops a characteristic coating of powdery, gray-brown fungus. The fungus can also attack canes, spreading from infected leaves into the cane and causing pale brown or "watermarked" gray and white lesions. The cane infections may also show fungal growth during humid conditions. The fungus typically overwinters in diseased plant debris and can be spread by wind and splashing water. The disease thrives in cool, moist weather and may cause serious fruit losses. Black raspberries are commonly less affected by fruit rot than are red raspberries.

Management Options

Non-Chemical Management

'Chilliwack', 'Comox', 'Fairview', 'Meeker', 'Munger', and 'Nootka' show moderate resistance to fruit rot, while 'Chilcotin', 'Meeker', 'Nootka', and 'Willamette' are resistant to cane infections.
Space plantings, prune, and train to provide good air circulation and reduce humidity.
Avoid overhead watering.
Provide proper culture. Excess fertilizer promotes dense, slow-drying foliage which may be more susceptible to disease problems.
Clean up all plant debris. Destroy or discard (do not compost) diseased materials.
Pick ripe fruit frequently and thoroughly to reduce losses. Avoid injuring fruit and cool promptly.

Select non-chemical management options as your first choice!

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides

None recommended

Images

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Caption: Botrytis on fruit Photo by: R.S. Byther
Caption: Botrytis on ripe fruit Photo by: Unknown
Caption: Botrytis on young fruit Photo by: R.S. Byther
Caption: Botrytis sporulating overwintering bodies Photo by: R.S. Byther
Caption: Botrytis overwintering bodies Photo by: R.S. Byther

WSU Extension

Hortsense