Best time to treat for Ash Borer
Please advise if it is too early to spray for Ash Borers - March 21, 2013.
We are scheduled for this service however opinions differ.
Arapahoe County Colorado
In a "normal" spring, first emergence and pheromone trap capture of lilac-Ash borers is in early-mid-April. The recommended time for trunk sprays of carbaryl or permethrin is about two weeks after first captures of adults in pheromone traps. So, roughly April 15 would usually be a good time for trunk application in Denver.