Drift Resulting from Ground-based Sprays of Carbaryl to Protect Individual Trees from Bark Beetle Attack in the Western United States

A common method of protecting individual trees from bark beetle attack in the western U.S. is to saturate the tree bole with carbaryl using a hydraulic sprayer at high pressure. With this type of application method spray deposition will occur off-target and may contact open waters where sensitive species are subject to the toxic effects of the pesticide. We report on a recent study in which the authors reported carbaryl drift resulting from single tree protection treatments poses little threat to adjacent aquatic environments, a primary concern when treating trees in campgrounds in the Western United States. Using reasonable no-spray buffers will ensure that adjacent aquatic environments are protected from any negative impacts.