How to Manage Pests

UC Pest Management Guidelines

SYMPTOMS

Blackberry and raspberry plants with Cladosporium fruit rot have berries that are covered with a soft, velvety, olive-green mycelial growth. While this growth is unsightly, it does not often damage the fruit. Cladoporium herbarum and C. cladosporoides can occur alone or in association with lesions caused by Botrytis cinerea (the causal agent of Botrytis fruit rot).

COMMENTS ON THE DISEASE

Cladosporium fruit rot of caneberry is primarily a postharvest storage disease. Even though these fungi cause little actual damage to fruit, the mycelial growth on the fruit is unappealing, so the fruit is unmarketable. Optimal temperature for the growth of these fungi is between 68° to 77°F (20° to 25°C), but may occur at lower temperatures during normal fruit storage.

This fruit rot is most commonly associated with fruit that is sunburned or damaged in some manner.

MANAGEMENT

Practice good sanitation and manage moisture within the planting to reduce inoculum levels and the risk of infestation. Harvest regularly and carefully, removing damaged and infected fruit. Cool berries as rapidly as possible to an optimum of 32°F (0°C).

Organically Acceptable Methods
Good sanitation and harvest practices are acceptable methods in an organically certified crop.

Treatment Decisions
Treat if weather conditions are favorable for the development of Botrytis and Cladosporium fungi (i.e., rain).

PUBLICATION

UC IPM Pest Management Guidelines: Caneberries
UC ANR Publication 3437
Diseases
S. T. Koike, UC Cooperative Extension, Monterey County
M. P. Bolda, UC Cooperative Extension, Santa Cruz County
E. J. Perry, UC Cooperative Extension, Stanislaus County
W. D. Gubler, Plant Pathology, UC Davis
L. J. Bettiga, UC Cooperative Extension, Monterey County

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