Oak Wilt

Oak wilt is a deadly fungal disease that infects and disables the water-conducting system in oak trees. All oaks are susceptible to this disease, but some species more so than others. With no known cure, methods to control and treatments are expensive and not guaranteed.

Oak wilt is prevalent in Central Texas and spreads both above and below ground. Fungal mats develop under the bark on the trunks and major branches of infected Red oak trees. When the fungal mat enlarges and cracks the bark of the tree, an odor is released that attracts sap-feeding beetles. The fungus is transmitted when these beetles feed on the fungal mats and carry fungal spores to fresh wounds or cuts on healthy oak trees. Because oak trees have interconnected roots, the disease can be spread below ground through grafted root systems, eventually killing great numbers of oak trees in the area.

Trees are an important public resource that enhance the quality of life, add value to properties and reduce energy costs and pollutants. Our City Arborist has some tips you can follow to help prevent oak wilt in your neighborhood.

• Minimize pruning oak trees between February 1 and July 1. this is when the oak wilt fungus is most active.
• Best time to prune trees is either in the middle of the summer, when temperatures are the hottest, or in late fall/early winter months when temperatures can be the coldest.
• Paint all cuts and wounds on oak trees within 30 minutes.
• Remove red oaks identified with oak wilt.
• Know where your firewood comes from. Don't transport unseasoned firewood from diseased red oaks.
• Make sure contractors doing tree pruning have a valid, City issued tree maintenance license and proper training.

If you suspect oak wilt in your neighborhood, contact the Texas Forest Service at 830-792-8885.