University of Manitoba - Faculty of Agricultural & Food Sciences - Strawberry Black Root Rot
Strawberry Black Root Rot

Problem type: Disease

Name of problem: Strawberry black root rot

Plant name(s): Strawberry

Symptoms / Characteristics:
White healthy roots become blackened on the outside with a yellowish interior. Feeder roots are destroyed shortly after infection and eventually the entire structural root decays. The plant exhibits reduced vigor due to the deterioration of the root system. Small leaves and pale leaf colour are common in infected plants. Severe infection may result in plant death.

Black root rot is a disease complex that may be caused by several fungal pathogens, including Pythium, Fusarium, and Rhizoctonia. These soil-borne pathogens are also the causal agents of the damping-off disease that occurs in seedlings of all plant types. Strawberry black root rot is often associated with acid/ alkaline and waterlogged soils. Winter injury also facilitates the development of the disease.

Control / Preventions:
The best way to defend against black root rot is to plant strawberry patches in well-drained soil. Heavy clay soils should be avoided, as adequate aeration is essential for the growth and development of strong, healthy root systems. Good aeration also stimulates soil bacteria to perform chemical reactions that are essential for nutrient acquisition by the plant. Also avoid excessive irrigation and soil compaction. Minimize winter injury in order to reduce the risk of future root rot. Placing a layer of wheat or oat straw over the plants protects the crowns from cold, dry winter winds and protects the roots by stabilizing soil temperature. Apply the mulch in late fall after frost has occurred but before temperatures dip below -6ºC. Be sure to remove the straw promptly in the spring. There is no registered chemical control for the disease.