This close-up photo depicts a moderate Hemlock Woolly Adelgid (HWA) infestation. These woolly, cotton-like egg sacs are most visible in late winter and early spring. They are found on the undersides of the branch and contain 90 to 300 eggs per cocoon.
This insect is decimating the hemlocks in the eastern US. I have witnessed this personally. In the high country along the Cherohala Skyway I have seen places where up to 90% of the hemlocks were already gone.
I'm not going to pretend to be an expert on the Hemlock Woolly Adelgid but I feel that these links have vital information on how to save this tree species. These organizations are working with government agencies and the public to help save this tree. Please contact them to learn what you can do to save your trees. There is hope. It just takes getting the word out.
In the winter and spring of 2010 we personally treated around 400 of our trees using imidicloprid according to recommended guidelines. The cost of the injector and chemicals was around $1000. (Prices have increased since then.) Four years later they appear to be HWA free and have alot of new growth.
These websites will get you pointed in the right direction.
Save Georgia's Hemlocks http://www.savegeorgiashemlocks.org/
Winner Atlanta's 2012
Cox Conserves Hero Award
Friends of the Blue Ridge Parkway http://blueridgefriends.org/index.cfm/fa/content.view/menuID/781.htm
Eastern Forest Environmental Threat Assessment Center http://threatsummary.forestthreats.org/