MSU Extension Integrated Pest Management

Rhizopus rot

Disease

Rhizopus rot

Rhizopus stolonifer (Ehrenb.:Fr.) Vuill.

Distribution: Widespread; common to all fruit-growing regions in eastern North America.

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Although the rot is predominantly a postharvest problem, symptoms may also develop in the field. Rotted fruit appears similar to brown rot, but Rhizopus-affected fruit appears slightly darker, the skin may slip away from decaying flesh underneath, or the fruit may be very leaky. Visible fungal mycelium may be white and fluffy, appearing like whiskers when the fungus sporulates. Infected fruit lying on the orchard floor or in packaged containers will often be engulfed by the fungus, appearing fluffy, with the fungus appearing to turning from gray to black as the fruiting bodies of the fungus develop at the tips of the "whiskers" (A, B).

• Crops Affected: peaches

  Management

  Pre- and postharvest chemical treatments and storing fruit at cool temperatures will help to reduce the incidence of Rhizopus rot on harvested fruit. In the orchard, minimize wounding, disease, and fruit feeding by insects as infection by Rhizopus usually occurs as the result of wound colonization.

  Similar Species

  This disease can be confused with brown rot in the early stage of infection.