If you have been on campus the last two weeks, you may have noticed a Bartlett Tree Co. spray truck parked around. They have been injecting our American elms, Ulmus americana, with Arbortet fungicide to protect them from Dutch Elm Disease, Ophiostoma ulmi.
This treatment is done every two years in even numbered years. Small holes are drilled into the root flare of the tree and small nozzles connected to plastic tubing are inserted. The diluted fungicide is then injected under pressure into the sap stream of the tree to be carried throughout the tree.
Dutch Elm Disease first arrived in America in the 1920’s creating devastation through the American Elm population. This fungus attacks the vascular system of the tree and causes it to plug up the xylem and phloem. The clogged vessels cut off the flow of water and nutrients to the branches and cause the tree to wilt and die. This can happen within months or even days. Elm bark beetle is the main carrier of this fungus, although natural root grafts of closely planted trees will also spread it.
We have some very massive American elms on campus between the Scott office and McCabe Library, and along the railroad tracks by Sharples Drive. So far the treatments have been working for us.