UMass Extension Landscape Message July 25, 2014
I saw European chafer adults flying in mid June, and have seen oriental beetles and a few Japanese beetles flying since early July. Sadly all these observations were in my own yard. The point is that the beetles are right "on schedule", which means many of the females are laying eggs now. That means that we are in a good period to apply a neonicotinoid to control the grubs that will soon be hatching from those eggs. Remember, however, that all the neonicotinoid labels specify that you should not apply the product on plants where bees are foraging. Since this seems to be a bumper year for clover in lawns, you need to be particularly careful and pay attention to details. (Studies conducted in Dr. Dan Potter's lab at the University of Kentucky indicate that theimpact of neonicotinoids on honey bees and other pollinators can be greatly reduced in lawn settings by mowing just before the application - at a height that removes the clover blossoms.) However, scientists are still trying to determine the impact of the neonicotinoids on flowering trees and shrubs that might be located near the turf application. "Discretion is the better part of valor", so in my humble opinion, when in doubt, you probably should avoid or delay the application until the trees or shrubs are no longer flowering."
Report by Dr. Pat Vittum, Professor & Extension Entomologist, UMass Stockbridge School of Agriculture and Interim Director, UMass Center for Agriculture Food and the Environment