| [College of ACES] | [University of Illinois] | [Illinois CES] |
You are right. The picnic beetle is responsible for spreading the fungus. When the fruiting bodies of the fungus burst, the spores can be blown by the wind.
For the last two springs I have worked with Jennifer Jeswick at the University of Minnesota. Jennifer is researching a naturally occuring innoculant to spray on oaks. They go out early in the spring to mark spore mats. Then they spray the trees with their "soup" to see what results they get. the part that I play is to go out and chop out and grade the spore mats. Fun work for a couple of days in the spring. Squirrels will get into the spore mats to eat them. When the spore mats are ripe they have a very pleasant, candy smell. I never tasted any but it was tempting.
By airborne, i meant transmition through the air. The other way that oak wilt can transfer is through root grafts. These can occur at any time of year. I always let my clients know about the different vectors of transmission of oak wilt. I am careful to let my clients know that the trees can get oak wilt after the spring window. There is really no practical way to prevent root grafts unless you want to bring in a six foot vibratory plow. That is done in some areas out in the woods but not a lot in residential areas.
Tom Dunlap