Phytophthora represents a group of fungal-like organisms that cause crown rots, root rots, and trunk rots of many trees, shrubs, and flowering plants. The name "phytophthora" means plant destroyer. It is sometimes referred to as a water mold because it grows and reproduces best in standing water or saturated soil or media. Excessive irrigation or rainfall combined with poorly drained soil favors disease development. Plants infected with this root rot show a variety of symptoms. Shrubs may wilt as if they are affected by drought stress, even though plenty of water is available for uptake. Leaf yellowing, leaf curl, stunting, and dark, decayed roots may develop on infected plants. Affected plants die once their root system is killed. Prevention - Disease-free plants are a must to prevent Phytophthora from becoming established in landscape beds. Plants grown in containers should be examined for symptoms of root rot before purchase. Physical control - Ericaceous plants should be grown in raised beds if clay is the predominant component of landscape beds. Two to 4 inches of pine bark may be incorporated into beds to improve drainage and raise the height of the bed. Chemical control - Fungicides are helpful in preventing infection but of limited use after a plant becomes infected. Remember, fungicides are best used as preventive treatments and may be of little value to infected plants, especially if site conditions are favorable for phytophthora root rot. Contact your local Extension office for information on specific fungicides.

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