Oak wilt kills both red and white oaks. It spreads mainly through root grafts between adjoining oak trees, but insects may also spread spores from infected trees to fresh wounds on other trees. Oaks usually die in pockets in the woodland. Avoid pruning oaks or wounding their bark from April through July when spores are being produced. If an oak wilt infection is present, harvest infected trees within four weeks of wilting, and harvest non-infected oaks for a distance of 100 feet beyond the infected trees. In high value stands, cutting root grafts with a vibratory plow or by chemical means may stop the disease from spreading.