Black root rot may be caused by several factors, known as a "disease complex." This complex is associated with a number of pathogenic soil fungi especially Rhizoctonia and Pythium species.
Gray mold, or Botrytis blight, is a common disease of a number of non-woody plants worldwide and causes a greater loss of strawberry flowers and fruit than any other disease. The causal organism, Botrytis cinerea, can live as a parasite as well as a saprophyte on decaying plant debris.
There is a wide array of leaf spots that infect the cultivated strawberry and often wild strawberry species. Some are known as leaf spot (birds-eye leafspot), black leaf spot, Septoria leaf spot, Cercospora leaf spot, Alternaria leaf spot, red spot, and Angular leafspot. These leaf pathogens are caused by several fungi and may occur with other foliar diseases. Usually, disease development is favored by rain and warm, humid weather.
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.
Red stele, or red core, is the most serious disease of strawberry. In areas with cool, moist soil conditions, especially soils heavy in clay that are saturated with water during cool weather, the disease is more prevalent. Red stele is caused by the soil-inhabiting fungus Phytophthora fragariae.