Leather or crown rot occurs in most temperate regions of the world on a wide variety of plants. Infection is favored by warm, wet weather and poorly drained soil. 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 can develop along with the fruit rot.
Symptoms and Disease Cycle
Crown rot is caused by the soil-inhabiting fungus Phytophthora cactorum. The pathogen infects the roots of the strawberry through wounds in the root tissue. 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 can appear either without color change or bleached and ranging in color from light lilac to purple. Fruit rot occurs when berries come in contact with the soil. A serious crown rot can develop along with the fruit rot. 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 fruits by splashing rain or wind.
Practices, such as mulching, that keep the fruit off the ground and aid in minimizing rain splash will help control leather rot. Growers also should plant resistant varieties, provide good soil drainage, and avoid planting in low spots.