I went with Bayer Tree & Shrub (1 oz. per 1" circumference in a 2gal.
Watering can). 2 gal. covered 8 trees of between 22" and 54" and I've got to
get another 2gal. for the rest of the hemlocks. As you say, it is late, and
since Maryland tends toward dry summers I'm figuring on watering the trees
heavily to get the systemic treatment absorbed by the roots. According to my
local garden center (River Hill) it should take effect in about a month and
the results are dramatic.

JP (West Friendship)


Most of the reasonably knowledgeable folks I have discussed this with here
(also Maryland) tell me they have had best luck with systemic treatment.
You need to get the Merit into the soil so the roots suck it up. I had
decent success using granular Merit & scratching into the soil / mulch
area under my hemlocks, then watering it in thoroughly. It may be too late
in the season by now to control them this way.

There are tons of articles on the subject by various regional
Universities. One short concise one is he

http://www.uky.edu/Ag/Entomology/ent...rees/ef452.htm

I also used granular Merit in the soil at the base of my Purple Leaf Plum
trees to help with controlling Japanese beetles, both the grubs in the
soil as well as the adults munching on the leaves. The numbers of dead
adults under these treated trees was amazing.

David in Olney