My Western Hemlock is infested with woolly adelgid. Help! How can I save my tree?
The USDA Forest Service website
includes information on different ways of managing the Hemlock woolly adelgid.
The most effective approach is prevention, as treatment tends to be expensive
and is not always effective. Information from University of Maryland Extension does describe the use of dormant oil spray in late winter and summer application of horticultural oil and
insecticidal soap, but care must be taken to cover the entire tree. Also, it is
important to avoid the use of nitrogen-heavy fertilizers which create a lot of
succulent new growth attractive to the pest.
I recommend that you consult a certified arborist for advice on how to save your <em?Tsuga heterophylla (Western hemlock). You can obtain
referrals from Plant Amnesty or you can select an arborist from the directory of the Pacific Northwest Chapter of the International
Society of Arboriculture.