Leather rot occurs in most temperate regions of the world on a wide variety of plants. It is caused by the soil-inhabiting fungus, Phytophthora cactorum. The fungus attacks berries in the field at all stages of growth. Fruit rot occurs when the berries come in contact with the soil. The pathogen may also cause a serious crown rot, which may develop along with the fruit rot.

Symptoms

Symptoms are different depending on the fruit stage. On immature, green fruit, the infected areas appear dark brown or normal green with a brown edge. On ripe, mature fruit, they appear bleached and range in color from light lilac to purple, or there may be no change in color. Infected fruits are characteristically tough and leathery, having a bitter taste. When weather conditions are warm and rainfall is abundant, the pathogen releases its spores into the soil. These infested soil particles are dispersed onto the fruit by splashing rain or wind.

Disease Cycle

Phytophthora cactorum is a fungus that is always present in the soil and possibly exists in all strawberry plantings. Only when weather conditions are favorable does this fungus become a pathogen. Infection takes place through wounds in the strawberry root, when spores are splashed with soil particles onto flower parts and when ripe fruit are in contact with wet soil. The fungus produces motile spores that can "swim" when free moisture is abundant.

Disease Management

Practices such as mulching, which keeps the fruit off the ground and aids in minimizing rain splash, will help control leather rot.