Want to protect several cornus floridas from dogwood borers in zone 5/6 northwest NJ. Arborists explained that our favorite 15 foot Cornus florida native just died from borers. It was a native that was probably damaged by construction 20 years ago and died a long slow death. Was hoping for a clean simple solution avoiding nasty spraying. But my on-line research seems to indicate that Bayer Advanced Tree & Shrub does not work for clear winged dogwood borers. It does appear to work great for Pieris japonica lacebugs though. What is the best way to protect the Cornus floridas? Also have some kousas. Do these need to be protected from the borers if they are otherwise very healthy?