What Is Wrong With My California Bay?

Are there any entry holes in twigs or branches?

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

Are the leaves yellow and the plant looks weakened, tiny, white insects are present?

Do the leaves have any small circular or irregularly shaped dry spots that are gray to straw in color?

Are there any small, black angular spots or large, irregular brown spots on foliage?

Is the tree's growth stunted, cankers may be visible on the trunk?

Are there any discolored, sunken cankers on twigs, stems, and trunks; orange fruiting bodies may be present?

Leadcable borers tunnel into twigs or branches, often at the crotch. It may cause twig dieback. Adult beetles are black or brown and about 1/4 inch long. Prune out affected plant parts. Remove and dispose of nearby dead wood, which is where the beetles breed. Chemical control is ineffective once beetles have infested a tree.

The 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.

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.

These symptoms indicate a fungal disease - Anthracnose. Keep plants dry when watering to prevent spread. Spray plants with copper when the first fruit develops if you have had problems in the past. Bordeaux mixture can also help to protect the plant from the disease.

Bacterial blight (caused by Pseudomonas syringae) Causes small, black angular spots or large, irregular brown spots on foliage. Branch cankers and brown streaks in the wood may also occur. The spread of the disease is greatest during humid, wet weather conditions. Practice good garden hygiene at the end of the season and discard, do not compost, possibly diseased plants and plant parts. Pull out and destroy infected plants.

Twig dieback and trunk cankers damage and kill the cambium, which is responsible for tree growth. Vigorous trees may be able to tolerate multiple cankers for several years, but some infected trees rapidly decline and die within 1-2 years. Bark becomes discolored, then peels off to reveal blackened and cracked wood. The two diseases are often present together. Monitor trees for early signs of the diseases so that they can be caught early. Pruning infected branches, shoots, and flowering stalks can be somewhat effective at slowing the progression of the disease.

Nectria canker on trees is a fungal infection. The pathogen known as nectria invades fresh wounds and damaged areas of bark and wood. Orange fruiting bodies appear during spring and summer. Nectria rarely kills older, established trees. There is no cure for nectria canker. Prevent it by avoiding pruning during wet conditions, and by protecting your trees from winter injury.

Heart rot is a fungal disease that may cause problems in California bay. 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.