Two-lined chestnut borer
Oaks weakened by drought, defoliation, or wounding are targets for the two-lined chestnut borer, Agrilus bilineatus. After chewing their way through the bark, adult beetles lay eggs which hatch into very slender, flattened white larvae that have two spines at the end of their abdomens. As these larvae feed and tunnel through the live tissues of the inner bark and outer sapwood they girdle infested branches and trunks. Leaves wilt, turn a uniform brown, and usually remain attached for several weeks before dropping. Scattered oaks in Itasca, Aitkin, Crow Wing, Morrison and Mille Lacs Counties were killed in June and July. Many more oaks just have a dead branch or two. To prevent further damage, water the oaks affected by drought, if possible. Trim off the dead and dying branches his summer or fall then pile and tarp the wood for one year. Otherwise, dispose/ burn it before next spring.