Alternaria fruit rot on blueberries

Alternaria species are an abundant, ubiquitous component in the environment and are a natural part of the fungal micro-flora. At least 20% of all agricultural spoilage is caused by Alternaria species. Fruit rot caused by Alternaria species is one of the most important factors affecting the post-harvest quality and shelf life of blueberries.

Alternaria can infect the fruit beginning at the end of bloom and throughout the fruit development stage, up until harvest. Infections remain latent until the fruit ripens. In the field, sporulation by Alternaria spp. will often appear on ripe fruit, as sunken areas near the calyx covered with a dark green, velvety growth. Infected fruits exhibit a shriveling or caving-in of the side of the berry and become watery in storage.

The growth of Alternaria species in blueberries is especially problematic since it could result in accumulation of mycotoxins. The major Alternaria mycotoxins belong to three structural classes: the tetramic acid derivative, tenuazonic acid (TA); the dibenzopyrone derivatives, alternariol (AOH), alternariol methylether (AME) and altenuene; and the perylene derivatives, the altertoxins.

Alternaria fruit rot is a primary issue when fruit is not harvested in a timely fashion and overripens on the bush.
Alternaria fruit rot on blueberries