Black root rot is a disease complex causing root decay in strawberries. The problem is not caused by a single factor, but by a combination of environmental conditions and disease organisms. Some contributing factors in black root rot include root rot fungi, nematodes, poorly drained soils, winter injury, or any combination thereof. The symptoms of black root rot include wilting, leaf scorch, poor runner production, and general decline of plants. These above ground symptoms are a result of a poor root system.

To diagnose black root rot, plants should be dug up to expose the entire root system. When diagnosing, it is helpful to be familiar with the appearance of healthy roots. Healthy young roots are a creamy white color. As roots age, they become woody and the cortex (surface layer) darkens in color. The tissue immediately beneath the cortex remains white and firm in healthy roots. The roots of plants with black root rot may have a lack of feeder roots, root tips which are dead and stubby looking, and/or roots with a blackened cortex which sloughs off when scratched with a fingernail.

Black root rot is caused by a disease complex, therefore chemical control is seldom effective for home gardeners. The following cultural measures provide the best control.

• Remove weak, infected plants.
• Renovate old strawberry beds to keep the incidence of black root rot low.
• If the bed is in heavy, poorly drained soil it may be necessary to establish the beds in a new, sunny, well-drained location.
• Replant with healthy winter-hardy varieties from reputable growers.
• Mulch properly to avoid winter injury.

P239S
Revised 11/99
Chad Behrendt, Crystal Floyd