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
|
