Hello:

Regarding the woolly adelgid problem on Hemlock trees:

Live outside of Boston.

Very confused over when the "best" time to spray is.

Spoke to a few arborists that do this, but i have the feeling they have a
stock answer that
the best time seems to be whenever one calls them.

Might someone please summarize for me when I should have spraying done, and
what treatment (oil, soap, type, etc. ), when in the year ?

Is the above answer different if one sees no problem, but wants to prevent
one, vs
the belief that there is already a problem.

Much thanks,
Bob