Blueberries: Fruit shrivels or rots prior to harvest

Common causes:

Drought

Blueberries do not wilt as readily as many other plants. Berries will shrivel and drop before leaves die.

Blueberry bush with several branches with tan, dry leaves. Most branches are healthy and green. Ripe blueberries on bush appear slightly shriveled.
Drought affecting a blueberry planting. Photo courtesy of Laura McDermott.

Frost Injury

Frost injury causes fruit to have a dark, shrunken appearance that readily distinguishes them from unaffected fruit. Severely damaged fruit appear hollow when cut in half. Frost or freeze injured fruit may drop to the ground prematurely before harvest.

View pictures (Mississippi State University).

Anthracnose fruit rot

Anthracnose fruit rot is caused by the fungus Colletotrichum gloeosporioides. Blossom and twig infections also occur. Spores from these early infections may be rain splashed onto developing fruit.

Blueberry twig ending in blossoms. Blossoms and twig are shriveled and wilted and salmon-colored. There is a sharp line on the twig above which healthy green tissue is visible.

Fruit Infections may occur from bloom to fruit ripening. This fungus causes the berries to “leak” and have a shrunken appearance, especially near the blossom end of the fruit.

Cluster of blueberries on branch. Half of the berries are shriveled and dark. Some berries are entirely shriveled, some are plump at the stem end but symptomatic at the blossom end.
The blossom end of blueberries will shrivel first, following anthracnose infection.
Cluster of blueberries with wrinkled, orangish areas on sides of berry.
Blueberries infected with anthracnose fruit rot.

Later, an orange or pink slime develops on the berry surface.

Close-up of blueberry fruit oozing salmon-colored liquid from multiple, small spots in the flesh. Ooze is evenly distributed across the berry and can be seen inside of the crown.
Anthracnose ooze on a blueberry fruit.

Alternaria fruit rot

Alternaria fruit rot causes black or dark moldy growth on the blossom end of the berry. Berries later shrivel and darken.

Dark black, shriveled berry cluster on a blueberry twig. Berries and stem are entirely black and severely wrinkled.

Mummy berry

Mummy berry infected fruits shrivel and turn pink. They are inedible. Mummified fruit drop to the ground prematurely. These overwinter to cause primary leaf infections the following spring.

Cluster of ripe and ripening blueberries. Several berries are blue in color but very small and shiveled.

Cluster of ripe blueberry fruit. Numerous berries are shrunken and shriveled. Shriveled berries are either gray-blue, or blue with orange-colored sections.

Cluster of ripe and unripe blueberries held in hands. Several berries in cluster are shriveled, and one has striped appearance when viewed from above from blossom end. Striped berry has alternating streaks of dark blue and pale, pithy orange.

Stripy looking blueberry held in hands. Blueberry peel has turned pithy and orange in color. The peel has been partially removed to show deep blue-black flesh of berry.