HWA Controls

The hemlock woolly adelgid is a tiny insect with an enormous capacity for destruction in a complex ecosystem.  And when the question is, "How can we get rid of these pests?" the answer is far from easy.  Sadly, the short answer is that we cannot, and probably never will, get rid of them completely. 

Perhaps the more appropriate question is "How can we control them?"  Again, the answer is not simple, but scientists believe that by using a combination of methods, it may be possible to control HWA populations and the damage they cause to such an extent that the hemlocks can survive and even thrive again.

There are three main categories of HWA controls: cultural, chemical, and biological.  Property owners should use a combination of cultural techniques and chemical treatments for the most reliable and cost-effective HWA control.

High priority stands of hemlocks on public lands (national forests, state parks, recreational areas, etc.) are being treated with carefully managed programs of chemical and/or biological controls; please see Hemlock Conservation Areas (HCAs).

Some Imidacloprid products in liquid formulations are more economical than the powdered products.  See the  Chemical Controls page for their names and the Contacts page for sources.

A fourth predatory beetle, Scymnus coniferarum, has been identified in the Pacific Northwest, but we are not sure if or when it will be designated for release on eastern forests.  In addition, two species of silver flies in the Pacific Northwest are showing promise as potential biological controls for hemlock woolly adelgid in the eastern U. S.