Phytophthora Root Rot is a widespread but often overlooked disease of landscape plants. These fungus-like organisms attack many species including rhododendron, holly, boxwood, hemlock and dogwood. Oaks, beech, fruit trees and maple are also susceptible.
Common on soils that are poorly drained, or those that receive excessive irrigation, symptoms vary depending on the impacted species. Diseased roots are discolored, lack fine roots and are pulled apart easily.
When soil moisture and temperature conditions are favorable for disease development, Phytophthora can increase rapidly. Infection can occur months or even years before visible symptoms appear.
To help prevent infection, ensure the root collar is exposed – not buried in soil and mulch. Improvement of soil drainage will also help. Species planted on sites subject to saturated soils may require periodic treatment to minimise infection.
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