Taphrina communis (Sadebeck) Giesenh.
Infections occur soon after blossoms open and are first evident on fruits when they reach 6–12 mm in diameter. Symptoms first appear as white to off-white spots or blisters that enlarge rapidly to cover the entire fruit. Infected fruit are distorted, spongy, and abnormally large (A). The tissues of the seed cavity wither and die, forming a pocket within the fruit (B). As the fruit dry, they turn velvety gray as a result of spore production on their surfaces, eventually turning brown, withering and falling from the tree. Diseased leaves are thickened and curled, similar to peach leaf curl. Symptoms on leaves may or may not coincide with fruit symptoms.
Common to all fruit-growing regions in eastern North America.
This disease is easily controlled with one well-timed fungicide application, most effective when applied either in autumn after 90% of the leaves have fallen, or in spring just before bud swell.
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