How to spot oak wilt

Facts below come from Texas A&M (AgriLife / Forest Service) and TexasOakWilt.org. Only a trained professional or a lab test can confirm oak wilt.

Live oaks

• Veinal necrosis: leaf veins turn yellow, then brown. This is the most telling sign.
• Leaves drop fast. Dead leaves with brown veins can sit under the tree for months.
• Most infected live oaks lose their leaves and die within about 1 to 6 months after symptoms show, though some take longer.
• Look for a pattern: dying oaks spreading outward from one spot.

Red oaks (Spanish oak, Shumard, blackjack)

• Most susceptible. They rarely survive and can die in about 3 to 6 weeks.
• In summer they can stand out from a distance with fall-like red or bronze color.
• Leaves turn pale green or bronze from the edges inward. Young spring leaves just wilt and brown.
• Dead red oaks can grow sweet-smelling fungal mats under the bark, which is how beetles carry the disease to new trees.

How it spreads

• Through roots: mainly in live oaks, about 75 feet per year on average. This causes most of the spread in Central Texas.
• By beetles: sap beetles carry spores from fungal mats to fresh wounds on healthy oaks.

The February–June rule

Avoid pruning or wounding oaks February through June, when beetles are most active. Paint every oak cut, wound, and fresh stump immediately, any time of year. Never store unseasoned wood from infected red oaks near healthy oaks.

Think you have it?

Don't wait. Have a qualified arborist look, especially if nearby oaks are connected by roots. Request a free match