Your County Extension Agency likely has a brochure on the issue, including strategies that work in your area.

Dan

Pay close attention to the dogwoods so that you can spot them while still very small. VERY small. That's when they are fairly easy to control with insecticidal soap applications. I suspect that very early applications of neem (cold pressed) oil would be extremely effective for this insects, too. The active ingredient in Neem acts as a growth regulator. Again, applications need to be made very early in the hatchlings' development.

As Dan suggests, your local extension office may have some pertinent information for you, such as when to begin looking for the tiny hatchlings. I expect that egg laying begins in May or June in your location, but the extension office will know for sure.

I agree with rhizo about the Neem, but the timing has to be right. In your area the Extension folks should have information about timing.

Dan

Yep, the timing of such applications is very important.

FYI...I did contact my local state agricultural extension ? office and what they said was that in addition to horticultural oil and insecticidal soaps i could use imidcloprid...sold as Merit..water in in late April,early May. I'm thinking I'm going to go for the big guns d/t the extent of the problem over past few yrs! Hope this helps anyone else who has had the same problem.