When is the best time to spray for those ladybugs (asian beetles), boxelder bugs and/or cluster flies? Why did my technician recommend I have my house treated in the fall?
The best time is in the fall, roughly from September 15th to October 15th. That is when the bugs are coming in from the fields looking for warm places (inside your house) to spend the winter. With that said, we can spray just about any time, but with lesser results. We do a bunch of houses in the spring, but 99% of those houses were not done the previous fall.
NOTE re: BOXELDER BUGS - If you have a Silver Maple tree near your house you may see these mid-summer, but not in the fall. Best treatment for mid-summer boxelder bugs is to rake the Silver Maple seeds from your lawn and clean them from your gutters. Then dispose of them away from the house.