Ligustrum Pests

Insect Pests

• Insects with sucking mouthparts such as aphids, scale, mealybugs and mites find the juicy ligustrum foliage irresistible. These insects can cause foliage to shrivel or become deformed, lose color and fall off the plant. Aphids, scale insects and others excrete a sweet, sticky substance called honeydew that attracts ants and bees and provides a good environment for the development of sooty mold. Japanese beetles are voracious feeders and can turn a healthy leaf into a skeleton overnight. Weevils chew oblong holes in foliage.

Diseases

• Diseases caused by fungal infections, bacteria or viruses cause leaf spots, twig blight, cankers and root rots in ligustrum. Some insects can carry diseases to the plant, as well. Leaf spots may be tan, yellow, gray or black and may be round or have an irregular shape. Some cankers are lesions on the woody areas such as branches. Root rot can cause the plant to suddenly wilt, or make the foliage turn yellow. Take a sample of infected plant material to a laboratory for proper diagnosis. This will help you choose the proper fungicide, miticide or bactericide to treat your plant's specific pathogen.

Mildew

• Powdery mildew is a fungus that makes the ligustrum's leaves appear as if they've been dusted with baby powder. The "powder" is actually spores. Powdery mildew can distort the foliage and cause the leaves to turn yellow and fall. Powdery mildew spreads during the humid days and cool nights of early spring and does not need moisture to travel. Avoid handling the plant while it is wet so you don't accidentally spread the disease. Prune out as much of the infected parts of the ligustrum as possible. Use a fungicide before the spores begin to spread and spray both sides of the leaves.

Cultural Problems

• In hot climates, ligustrum can suffer leaf scorch in summer. Leaf scorch and heat stress cause the leaves turn brown along the margins or between the leaf veins. The foliage may turn completely brown and dry up. Mulch the plants to help keep the roots cool and conserve moisture. Water the plant thoroughly and deeply, especially during extended periods of dry, hot weather. Keep the plants healthy to help them withstand adverse conditions.

Prevention

• Pull weeds, rake up plant debris around the privet and dispose of the material away from the garden to help eliminate diseases and insects that may be lurking. Cut out infected areas of the plant and prune to improve air circulation. Disinfect the blades on shears and clippers between every pruning cut you make. Water ligustrum from below, or water early enough in the day for the foliage to dry out before dark. Plant disease-resistant ligustrum species.