Black root rot is known as a "disease complex," meaning that it can be caused by several factors.
Gray mold, or botrytis blight, is a common disease of a number of nonwoody plants worldwide and causes a greater loss of strawberry flowers and fruit than any other disease. It is found on green as well as ripening and harvested fruit.
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 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.
Powdery mildew occurs on a wide range of hosts and almost everywhere the strawberry is grown. It is observed mostly as a foliage disease, but it occasionally causes a serious fruit rot. Severe foliar infection can damage leaves and reduce photosynthesis.
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.
Verticillium wilt of strawberry, caused by the soilborne fungus Verticillium albo-atrum, occurs throughout the temperate zones of the world, infecting more than 300 kinds of cultivated plants. Its hosts are annual and perennial crops as well as weed species.