Hemlock Disease

Hemlock Woolly Adelgid Ovisacs

Hemlocks are beautiful. Eastern Hemlocks (Tsuga canadensis) are abundant around throughout the Taconic Mountains. Without hemlocks, the Taconic Mountains would lose a lot of character. Yet native to Asia, the hemlock woolly adelgid (Adelges tsugae) is a small, aphidlike insect that threatens the health and sustainability of eastern hemlock.  According to the USDA Forest Service, the hemlock woolly adelgid can attack all species of hemlock, but the eastern species are most vulnerable. The woolly adelgid feeds on stored starches that are critical to the tree's growth.

I haven't looked closely at our hemlocks yet, but I will certainly be doing so once it warms up. It may take 250 to 300 years for a hemlock to reach maturity and may live for 800 years or more -- that is unless attacked by a woolly adegid and left untreated, in which case expect it to die in less than 10 years!

So far, no sign of Emerald Ash Borers, in Rensselaer County but it's another threat to be cognizant of.

Read more:

• Diseases of Hemlock Trees
• Emerald Ash Borer
• Hemlock Disease Factsheets
• Ontario Extension Note: Eastern Hemlock
• Pest Alert: Hemlock Woolly Adelgid