Oak trees are well known for their foliage that gracefully drops well into the heart of autumn. Help your oak stay healthy and avoid the common diseases that plague oak trees, robbing them of their cool-season display. Fungal diseases are at the top of the list for oak tree disorders. Gardeners should watch carefully for signs of an infection, and act accordingly.
Anthracnose is a fungal disease that cause scattered, small brown spots or light brown blotches to form along the veins. The disease also causes an oak tree's leaves to look scorched. Anthracnose is spread by rainfall.
Diplodia canker is a disease that affects the twigs and small branches of the coast live oak and the valley oak. Once infected with this disease, oak trees appear shabby due to a loss of foliage and color.
Oak Root Fungus
Oak root fungus is a disease that primarily attacks oak trees that have been injured by over-pruning, compaction or root cutting. Once infected, oak trees with this disease suffer from thinning foliage. In advanced stages of the disease, stem cankers can be seen bleeding or oozing from the trees' bark.
Oak trees growing in close proximity to a coastline are susceptible to powdery mildew disease. The disease typically affects young trees, giving their leaves a needle-like appearance and preventing them from developing.