Alternaria fruit rot

Alternaria alternate (Fr.:Fr.) Keissl

Distribution: Common to all fruit-growing regions in eastern North America.

Photos

Red cherries show velvety dark green to black, circular, sunken lesions. Alan Jones, MSU
B

The disease appears as velvety dark green to black, circular, sunken lesions on mature fruit; the infected tissue is firm and brown (A, B). Disease is typically associated with over-ripe or damaged fruit, or fruit held in storage (where serious losses can occur). The pathogen has also been reported to cause superficial red spotting on the surface of apricots and peaches. The spots eventually turn tan to brown, becoming necrotic, but typically retaining a red halo.

Crops Affected: apples, cherries, peaches, pears

Management

Avoid damaging mature fruit particularly during harvest. There are no practical chemical control recommendations.

Similar Species

On stone fruit, this disease can be confused with brown rot or Rhizopus infections. Rhizopus infections, however, tend to be softer than Alternaria-infected fruit. Brown rot-infected fruit will produce powdery gray to light brown spores, whereas Alternaria-rotted fruit will develop a dark green to brown mass of spores.