Often gum exudes profusely from active lesions. The dead bark frequently breaks away from the wood in vertical strips. Callus tissue begins to form on the margin of the surrounding healthy bark if the fungus becomes inactive because of unfavorable weather conditions. The disease may become active again when conditions become favorable. If the lesion encircles the trunk, girdling occurs and results in death of the tree.
Healing is slower if infection occurs below ground level.
The fungus may attack young feeder roots, causing them to decay. Infection of lateral and fibrous roots can become widespread in wet soils. This infection results in poor health of the tree, a thin canopy, failure to make new growth and poor fruit production. Examination of the crowns of infected trees shows symptoms similar to those described for older trees. Phytophthora foot rot can best be controlled by preventative practices, including use of resistant rootstock and planting in well-drained land.