Oak wilt weakens white oak trees and kills red oaks within weeks of infection. Bacterial leaf scorch is a chronic disease that worsens over several years. Both diseases spread to nearby oaks.

The diseases are particularly severe on American sycamore, the white oak group, black walnut, and dogwood. The greatest impact of anthracnose is in urban environments.

Oak trees with wounds in their bark are susceptible to the disease, which can weaken white oaks and kill red oaks within a few weeks. “Oak trees should not be pruned between April 15 and July 15.

Oak wilt’s onset can be confused with other more common issues, such as drought stress, leaf loss from spongy-moth caterpillars, and diseases such as anthracnose and bacterial leaf scorch.

Mark Runkel, an Iowa DNR forest health technician, and John Mullen, a GIS analyst for the department, walked out into a stand of trees at Hickory Grove to look for white oaks with signs of oak wilt.

Oak wilt is one of the deadliest tree diseases in the U.S., responsible for killing millions of trees across 76 counties in Texas, according to the forest service.

Oak wilt is a fungal disease that can weaken white oaks and kill red oak trees within just a few weeks. The fungus enters the tree through wounds that are often caused by pruning or storms.

An invasive insect from Europe and the Middle East is attacking several Oregon white oak trees in the Wilsonville area, ... The fungus grows, robbing tree canopies of water necessary for growth ...

Oak trees are special for many reasons: they’re Iowa’s state tree, they’re important to our ecosystem and — they shouldn’t be pruned during the spring growing season.

Oak wilt weakens white oak trees and kills red oaks within weeks of infection. Bacterial leaf scorch is a chronic disease that worsens over several years. Both diseases spread to nearby oaks.