Blueberry Facts

Botrytis blight and fruit rot
Botrytis cinerea (fungus)
Annemiek Schilder, MSU Plant Pathology
Bill Cline, NCSU Plant Pathology

Botrytis blight and fruit rot is a minor disease in most years but sometimes causes serious damage. Economic losses are mostly due to blossom blight and fruit rot.

		Symptoms On leaves, brown, irregular lesions develop that sometimes distort leaves. Blighted blossoms turn brown and soon become covered with abundant gray mold. Infected twigs are first brown to black and later become tan to gray.
Leaf lesion (left) and twig blight (right) caused by Botrytis.

Developing berries can also become infected, but fruit rot usually does not develop until after harvest. Infected berries become covered with a fluffy gray mold.

Disease cycle
The fungus overwinters as mycelium or hard black mycelial masses (sclerotia) on infected plant material. In spring, numerous airborne spores develop on plant debris and sclerotia. The fungus infects tender green twigs, blossoms, leaves, and fruit. Older plant parts are rarely attacked. Moderate temperaturers (59 to 68ºF) and frequent rains favor disease development.

		Management Remove infected plant material; reduce humidity in the canopy; apply effective fungicides during bloom and fruit ripening; avoid excessive use of nitrogen fertilizer in the spring; cool berries rapidly after harvest.
Flower blight (left) and postharvest rot (below) caused by Botrytis.

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