The most distinctive symptoms of Phytophthora root rot are the brown lesions on roots of all sizes. In severe cases, nearly all roots may be girdled or rotted off. Symptoms include tan or brown spots with concentric rings. Phytophthora capsici also causes greasy, purple-brown stem lesions. Infection of plants occurs at any stage of growth when there is free water in the soil.
Damage is greatest in poorly drained, compacted, or overirrigated soils.
Avoid wide fluctuations in soil moisture, which predisposes plants to infection. Keep tops of bed dry to avoid buckeye rot of the fruit. Planting cereals as a rotation crop may reduce the level of infestation in the soil. The Regents of the University of California. All rights reserved.