What Is Wrong With My Coyote Bush?

Are there wet, sappy areas on the bark of the main trunk, which may crack?

Do the leaves have holes?

Are the leaves covered with small bumps?

Are the leaves covered with white powder?

Are there any irregular galls on undersides of leaves, leaf stalks, and/or new shoots?

Larvae of flathead borers tunnel beneath the bark, causing wet, sappy on the bark of the main trunk. Boring may kill limbs or entire trees. Prevention is the most effective management approach for flathead borers, which typically attack trees that have been previously injured or damaged. Providing proper care and protecting landscape plants from injury will make them less attractive to the borers. Avoid pruning spring-summer while adults are active. Properly dispose of infested wood material, as beetles may emerge from logs and attack nearby plants.

Several species of leaf-feeding caterpillars will feed on coyote bush leaves. They may also feed on stems, flowers, and fruit. Handpick and destroy caterpillars, or spray plants with BTK if caterpillars are feeding. Many foliage-feeding caterpillar populations are controlled by general predators, parasites, or naturally occurring viruses.

Leaves covered by small bumps are caused by scales. These tiny, shelled insects often feed on the undersides of the leaves, causing an unhealthy appearance with yellowish blotches on the upper leaf surfaces. Scrape off minor infestations with your fingernail. Prune out badly infested growth, or use a soft brush and soapy water to gently scrub the scales off the stems. Control scales by spraying insecticidal oil during the growing season.

White, powdery patches on the leaves are caused by a fungal disease Powdery mildew. Powdery mildew usually appears in damp places. Encourage good air circulation around the affected plants by thining them and any surrounding plants. Water plants from below to keep foliage dry. Any affected leaves should be cut off and removed. The appropriate fungicidal spray will protect your plant from further infections.

Gall mites and blister mites are known pests of coyote bushes. Landscape plants can usually tolerate some gall and blister mite damage, and no controls are known for most species. Aesthetic damage can be managed by pruning and disposing of infected leaves. When mites are abundant, it is important to conserve natural enemies and to keep plants healthy and vigorous.

Yellow leaves and stunted look are caused by whiteflies. These tiny, mothlike flies and their larvae feed by sucking plant juices. Whiteflies secrete honeydew, a sugary substance that makes leaves sticky to the touch. Control whiteflies by eliminating garden weeds and by introducing green lacewings in the garden. Spray infested plants with insecticidal soap every 3 days for 2 weeks.