What Is Wrong With My Tanoak Tree?

Are there any sunken areas in the wood of the branch, stem, or trunk that contain dead tissue?

Are the leaves covered with white powder?

Are there any mushrooms or fungus conks on the tree?

Do the roots and crowns have dark brown spots at the soil level?

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

Are there any tiny entry holes accompanied by frass in the bark of the tree?

Are the leaves curled and distorted, sticky to the touch?

Do the leaves have white, cottony clusters on them?

Are the leaves and twigs covered with small, armored insects?

Hypoxylon canker is a disease that attacks tanoak. Prune out and destroy dead branches and infested areas. Be sure to make pruning cuts at least 3 or 4 inches below the canker and disinfect pruners between cuts. Spray both the healthy and diseased sections of a tree with copper during and shortly after periods of excessive rain.

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.

Heart rot is a fungal disease that may cause problems for tanoak. This fungal disease enters trees that have been injured by a storm or improper pruning. Once the fungus enters the tree, it slowly rots the wood, weakening and eventually killing the tree. To prevent heart rot, prune the tree regularly to remove branches damaged by ice or wind.

These symptoms indicate fungal disease Phytophthora Root and Crown Rot. Phytophthora pathogens are favored by wet conditions, and the risk of disease can be reduced with good water management. The disease tends to affect plants in poorly drained areas, where susceptible plants are surrounded by standing water or saturated soil for prolonged periods. Provide adequate drainage and know the water needs of individual plants.

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 flatheaded 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.

Western oak bark beetle is native to California. It bores under the bark to create shallow galleries in which it lays its eggs. The beetle is considered a minor pest and tends to attack trees that have already been weakened by drought or are otherwise stressed. Control is usually unnecessary for the beetle.

Distorted and sticky leaves and stems are caused by aphids. These tiny insects cluster under leaves and on growing tips where they feed on plant sap. Leaves, stems, and buds get distorted and later leaves and flowers drop from the plant. You can control them by washing them off the plant with water spray. Insecticidal soap should be used only with severe infestations.

White, cottony clusters on leaves are caused by mealybugs. These tiny insects are covered with a fluffy white coating. They feed by sucking plants sap. They produce the sticky substance honeydew which makes leaves sticky. You can control them by washing them off the plant with water spray. Insecticidal soap should be used with severe infestations.

Small, armored insects on leaves and twigs are armored 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.

Mineral deficiencies can cause tip chlorosis or necrosis or cause foliage to discolor, fade, distort, or become spotted, sometimes in a characteristic pattern that can be recognized to identify the cause. When nutrient deficiencies occur, nitrogen and iron are the most commonly seen deficiencies. Apply only the mineral found to be deficient. Excess nutrients, on the other hand, cause symptoms like leaf tip dieback, marginal leaf chlorosis, necrosis (or burn), branch dieback, and pest problems. In this case, you should provide good drainage, and use good