adelgids treatment on Hemlocks

[Glenn Meyers]

Can anyone recommend the best way of treating a well established infestation of these critters in my neighbors and my hemlocks??

Thanks,

Glenn

[John McGaw]

If the trees are of a size where you can spray easily an insecticidal soap is possible. Otherwise, a systemic insecticide applied through soil drench is probably the best option. Injection systemic is another method used but typically it takes an arborist to do that and it is very expensive.

If you do a Google search for "treat hemlock adelgid" (without quotes of course) there are several articles that detail possible treatments.

I have at least 20 hemlocks on my property and am weighing the possibilities myself. Luckily I seem to have no active infestations (or none that I can see) and my trees are all

[symplastless]

I would not recomend injections and systemics of chemicals that are not good to eat for animals. many animails eat parts of the hemlock tree. If these chemicals go to the needles than they may well just be in the other editable parts of the tree. Other than that there is a lot on pesticides here:

trees do not tolerate fragmentation. Small disturbances such as post logging can have a great impact of hemlocks.

With respect to the adelgid of Eastern Hemlock. I believe they are a part of the clean-up crew. Think for a minute about the following information regarding Hemlock and decline there of. Too often the humans do nasty things to trees and their associates. then when decline starts. they blame it on the clean-up crew. A great example is in the Allegheny National Forest. In sections that were logged heavily years ago they have mortality which is blamed on drought. But wait, the wood that was removed would have been water reservoirs for plants and animals during dry time. Now with all their glory they are logging to address drought issues???????????? Anyway check this out and for a moment and say its true. Maybe this explains why Hemlocks in disturbed areas are declining. Eastern hemlock - Tsuga canadensis Hemlocks of sawlog size are notoriously subject to wind-shake (481), to radial stress cracks, and, following sudden exposure, to sunscald of the bark, and to death. These reactions may be the result of many adverse effects associated with a changed regime of solar heat and soil moisture and culminate in a decline often referred to as post-logging decadence. When hemlocks are left as residual trees following partial cutting, and when they are exposed, through road or other construction or clearing, they often die, even when their root area is covered with understory brush (661). Eastern hemlock is also considered to be one of the species most sensitive to sulfur fumes from smelters (1933). An interesting type of hemlock ring-shake follows sapsucker injury.

Reference: Hepting, George, H. July 1971 Disease of Forest and Shade Trees of The United States US. Dept. Agric. Forest Service Handbook Number 386 658 pages.

Sincerely, John A. Keslick, Jr. Arborist

Beware of so-called tree experts who do not understand tree biology. Storms, fires, floods, earthquakes, and volcanic eruptions keep reminding us that we are not the boss.