Deadly Fungal Disease Sprouts on North Texas Trees

Oak wilt, a deadly fungal disease, has been discovered in patches across North Texas.

The disease plugs the vascular system of red oak and live oak trees and essentially starves the trees of vital nutrients. It can kill a red oak in a just two weeks.

"It's almost impossible to treat a red oak," said Doug Andrews, the Dallas County extension director for the Texas AgriLife Extension. "By the time you notice you've got a problem with a red oak, you've got a dead tree or one that way beyond the ability to treat."

Live oaks can be saved if the disease is caught early enough. The telltale sign of oak wilt on a live oak tree is veinal necrosis, when the veins of a leaf turn yellow. The other symptom is "flagging," when a branch of leaves in the tree will show a different type of color pattern.

There is no cure for oak wilt, but it can be treated in live oaks to stop the spread of the disease. Arborists inject Alamo fungicide into the root system of the infected tree. Treatment is costly and complicated and has to be done a continual basis to save the tree.

If not treated, the disease can spread easily from tree to tree.

"You'll have a tree here and a tree here, and the roots will grow together and they transfer that disease from one tree to another," Andrews said.

If there is no intervention, the result can be an entire neighborhood of dead trees overcome by oak wilt.

"It can devastate real estate values as well as aesthetic value of a neighborhood and an individual home," Andrews said.

The disease is also spread by nitidulid beetles, which are attracted to the sap of a fresh wound on a tree. Experts advise residents to prune during only the coldest days in winter and during the hottest months of the summer, when the beetles are not a threat.