COMMONWEALTH OF PENNSYLVANIA
Department of Conservation
and Natural Resources
DCNR RELEASES PREDATORY LADYBUGS TO COMBAT HEMLOCK WOOLLY ADELGIDhttp://www.dcnr.state.pa.us/news/newsre ... id0601.htm
Here some more info for you.
Tips for maintaining hemlocks and avoiding or decreasing hemlock woolly adelgid infestations:
Do not disturb shallow roots with heavy equipment or by digging or tilling;
Keep hemlocks well-watered (apply about 1 inch / week around drip line) during droughts;
Do not place a bird feeder amongst your hemlock trees in infested areas of the state. Birds can transport hemlock woolly adelgid crawlers to your trees.
Remove large, heavily infested trees that can act as reservoirs for uninfested trees.
Clip and burn heavily infested hemlock branches. If you can catch the infestation early enough, this may significantly slow the insect's spread and build-up.
Do not change the grade (slope of the land) near hemlocks, such as excavations or tree wells;
Do not change water runoff patterns around hemlocks. Simply moving a downspout or installing a patio can stress these trees;
Do NOT fertilize trees infested with hemlock woolly adelgid with nitrogen. Researchers have found five times as many hemlock woolly adelgids on nitrogen-fertilized trees, regardless of whether fertilization occurred at infestation or six months later. Once an infestation has been eradicated, fertilize hemlocks lightly with a balanced fertilizer, such as 5-10-5, late in the fall.
When applying lime or weed killers to lawn areas, keep them at least 10 feet away from the drip line (tips of outermost branches) of hemlock trees.