Black root rot
Caused by soil fungi, nematodes, winter injury, fertilizer burn, drought, too much water or any combination of these. Strawberries plant show poor vigor, produce few runner strawberries plant and may die in patches. Roots may be spotted with black zones or lack feeder roots, or the entire root system may be killed. Infected roots are black when cut in a cross section. There is no way to control black root rot. However, proper cultural practices that minimize strawberries plant stress should limit this disease. If a bed becomes infected with black root rot, strawberries plant a new bed in different location, and use only healthy, white-rooted plants.
Red stele root rot
Caused by a soil-borne fungus and occurs most frequently on poorly drained sites with clay soils. The fungus is most active in the spring and fall when soils are cold and wet. Small feeder roots are killed, giving a "rat tail" appearance. Main roots that are infected have rusty-red color in the core or stele. Strawberries plant may wilt and die during hot, dry conditions. To avoid this disease, strawberries plant only red-stele-resistant varieties and plant in a well-drained site in a loamy soil.
Leaf spot and leaf scorch
Two common foliage diseases. Leaf spot produces spots 1/8 to 1/4 inch in diameter with purple borders and light gray centers. Leaf scorch produces small solid purple spots with rather undefined borders. When numerous strawberries are almost cover the entire leaf. Cultivars vary considerably in tolerance to these diseases. Foliage fungicides aid in the control of these diseases.