Over the past several years we have intermittently tried applying insecticides to our elm trees in an effort to slow down this insect. This year, one of our vendors, Davey Tree Care, is utilizing a new system to administer the pesticide that we feel will do an excellent job of striking the pest while greatly reducing any chances of harming non target organisms, including people and pets, on our campus. This system is called ArborJet and uses a pressurized cannister to push the insecticide into the cambium layer of the tree allowing the trees' own trans-evaporation processes to then move the product up the trunk and into the smaller branches and twigs where the scale is feeding. This is a much more direct application of the product than a soil drench to the roots of the tree. None of the product is disbursed into the surrounding environment and therefore cannot likely be contacted by non targeted or beneficial insects. Only the insects that puncture the trees and feed are subject to the insecticide. Most any insect feeding on the trees juices or foliage is not considered beneficial to the landscape.
Working within Integrated Pest Management practices means that in addition to using this pesticide, we will continue to practice other forms of plant health care for these trees, as well. This will take the form of continued dead wood removal from the canopy, small amounts of structural pruning, and supplemental watering. The sanitation of the dead wood is especially important in elms in order to lower the attraction of the bark beetles which can vector the Dutch Elm Disease.
The following photos show the insecticide being administered by a professional crew from Davey Tree Care Co. contracted to work on our campus.