Why Does My Holly Tree Look Unhealthy?

Are the leaves tunneled?

Are the leaves webbed together?

Are the leaves yellow and covered with small bumps?

are the leaves stoppled with yellow and the foliage is webbed?

Do the leaves have notched margins?

Are the leaves yellowed?

Have the leaves and shoots blackened, leaves have moist or brown sunken spots?

Do the leaves have spots on them?

Do the leaves have a powdery white coating on them?

Are the trunk and the branches of your holly tree oozing sap through the lesions?

Tunneled leaves indicate the most serious pest of hollies - Leafminers. Small maggotlike larvae tunnel through the leaves and feed on them, adults are black-and-yellow insects. Remove and destroy mined leaves. Apply row cover as soon as plants emerge to prevent problems. Use yellow sticky traps to catch adults.

Webbed leaves on holly usually indicate larvae of Bud moths. These greenish-white caterpillars web together and feed on the tips of new holly shoots in May. Fully grown larvae usually drop to the ground and overwinter in plant debris. Remove fallen leaves around plants. Destroy webs and handpick caterpillars. Spray leaves with BTK in April and May.

Yellow 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.

Spider mites often cause problems for holly trees and shrubs. You can control spider mites by spraying plants thoroughly with water 2-3 times a day for several days. For severe infestations, spray plants with insecticidal soap or pyrethrin.

Leaves with notched leaf margins on privet are caused by insects - Japanese weevils. Adult Japanese weevils feed on foliage, but the larvae attack roots exclusively. The application of a sticky substance on the lower stems should prevent adults from climbing up the plants. Introduce parasitic nematodes into the soil to control the larvae. Spray leaves several times with pyrethrin for severe infestations of adults.

Nitrogen deficiency causes leaves to yellow. This is usually most noticeable on older leaves. Regular fertilization helps keep hollies green and vigorous. Apply cottonseed meal or a generous mulch of compost in early spring.

The most likely cause for these symptoms is a fungal disease - Anthracnose. Keep plants dry when watering to prevent spread. Cultural controls such as regular fall cleanup and thinning to improve air circulation are effective. Treat severe problems with copper fungicide sprays.

Several kinds of fungi cause leaf spots on holly trees and shrubs. Spots may enlarge rapidly, especially in wet weather. Destroy infected leaves. Spray plants with sulfur to prevent the disease from spreading, especially if the weather is wet. Prevent problems by thinning plants to provide good air circulation.

If the leaves have a powdery white coating on them, the cause is a fungal disease Powdery mildew. Powdery mildew usually appears in damp places. Thin your plants to ensure good airflow. Water plants from bellow to keep foliage dry. Any affected leaves should be cut off and removed. Any commercial fungicidal spray will protect your plant from further infections.

Oozing lesion is caused by cankers. Cankers can be caused by several different kinds of fungi. Mildly affected plants will recover if you remove and destroy all affected branches. Heavily affected plants can't be cured and you should remove the whole plant. Avoid damaging your plant with lawnmowers, trimmers or pruning tools because the wounds are the best place for cankers to start.

If the leaves are mottled yellow the cause is probably whiteflies. These tiny, white, mothlike insects and their even smaller larvae feed on the undersides of leaves, weakening the plant. Spray leaves with insecticidal soap, or pyrethrin as a last resort and repeat weekly until pests are under control.