How to Manage Pests

Pests in Gardens and Landscapes

Pest identification and confirmation—Phytophthora

To confirm the presence of Phytophthora, cut away the outer bark around the stain streaks or canker. The concentric margins between the healthy whitish or yellowish wood and the reddish or brown infected wood in the trunk look as if they are soaked with water. Woody roots decaying from Phytophthora are firm and brittle. In contrast, roots destroyed by excess water are soft, although Phytophthora -infected roots eventually soften as a result of the action of secondary organisms.

Brownish streaks in roots indicate infection
Brownish streaks in roots indicate infection


Statewide IPM Program, Agriculture and Natural Resources, University of California
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