G3590
Lake States Oak wilt management— Woodlands what are the options?
Jane Cummings Carlson Trees at risk Biology and spread A. Jeff Martin housands of oaks in woodland of oak wilt and urban settings die from oak Mats of fungus, known as “pressure wilt every year. Widespread in pads,” develop under the bark of trees Wisconsin, Minnesota and that have died from oak wilt. Mats form Michigan, the disease is caused most often in spring, approximately 9- by the fungus Ceratocystis 10 months after a tree dies from oak fagacearum. Figure 1 shows the extent of wilt. These mats force the bark to crack Toak wilt in Michigan, Minnesota and open. The fungus produces a sweet Wisconsin. odor that attracts sap-feeding beetles Trees from the white and red oak such as Nitidulids. The beetles pick up groups, both found commonly in the fungal spores by crawling on the mats. Lake States, are susceptible to oak wilt. Then they fly to healthy oaks to feed on Because trees in the red oak group fall sap flowing from fresh wounds, thus prey to the disease most often, this pub- infecting new trees. lication focuses on the red oak group.