Phytophthora Root Rot (Rhododendron Wilt)
This disease is caused by one of several species of Phytophthora and is primarily a problem where wet soil conditions occur.
Symptoms
The leaves of infected plants look off-colored and eventually wilt. In the advanced stages the leaves are rolled lengthwise and the leaves and stems appear brown in color. The root systems of infected plants are greatly reduced. The remaining roots often appear water-soaked and brown.
Control
Buy only healthy plants from a reputable nursery. Avoid plants that lack normal green color or appear wilted. Plant in an area with good soil drainage and use raised beds if necessary. As a last resort, fungicide treatments can be used to prevent the spread of Phytophthora into and among plants. A fungicide used as a soil drench can be an effective treatment when used as recommended on the label.
Contact your local Extension office for fungicide recommendations.
