How to Manage Pests

UC Pest Management Guidelines

SYMPTOMS

Like the fungus that causes Rhizopus fruit rot, Mucor spp. invade the fruit through the slightest wound. The fungus secretes an enzyme that rapidly results in a leaky fruit rot. Under conditions of high humidity, the berry becomes covered with a coat of tough, wiry mycelium and black, spherical spore-bearing structures. Mucor and Rhizopus fruit rots closely resemble each other and may be difficult to differentiate in the field.

COMMENTS ON THE DISEASE

Because the fungus lives on dead and decaying organic matter, field sanitation is important.

MANAGEMENT

Remove all ripe fruit and plant debris from the fields. Remove and destroy all ripe and near-ripe fruit from fields after rains. Use plastic mulch to keep fruit from contacting soil. Practice good sanitation during harvest, packing, transport, and storage, and avoid damaging fruit at all times. Unlike Rhizopus, some Mucor species such as M. mucedo and M. piriformis are not inhibited by cold temperatures.

Cultural Control
Field sanitation is extremely important. Handle fruit with care at all times. Remove all ripe fruit from the field at harvest. Be sure when fruit is being picked that the entire fruit is removed from the stem, not leaving behind the fleshy receptacle of the fruit as it can serve as a site for invasion by fungus. Cultivars with thick cuticles are less susceptible to Mucor fruit rot because they are better able to resist infection.

Organically Acceptable Methods
Sanitation, cultivar selection, and rapid postharvest cooling are acceptable for use in an organically certified crop.

Treatment Decisions
Fungicide treatment is generally not recommended.

PUBLICATION

UC IPM Pest Management Guidelines: Strawberry
UC ANR Publication 3468
Diseases
S. T. Koike, UC Cooperative Extension, Monterey Co.
W. D. Gubler, Plant Pathology, UC Davis
G. T. Browne, USDA Crops Pathology and Genetics, UC Davis

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