Thursday, May 29, 2014


Today we're going to look at a pest that is devastating our woodlands. It is called the Hemlock Woolly Adelgid.  It is commonly pronounced WULL-ee uh-DELLjed.   (This article is taken from the PA DCNR.)

What is the Woolly Adelgid? The hemlock woolly adelgid is a sap-feeding insect that attacks hemlock trees throughout eastern North America along the Appalachian mountains and surrounding regions, including Pennsylvania. It is particularly bothersome to both the eastern hemlock (Pennsylvania's state tree) and the Carolina hemlock (found further south in the Smokey Mountain sections of the Appalachians). These adelgids are also found as far north as southern New

                               Woolly Adelgid

The insects appear as white sacs clinging to hemlock twigs, resembling the tips of
cotton swabs. These sacs are on the underside of the twigs at the base of the needles, making them hard to see at first.  Hemlock woolly adelgids feed throughout the year, although spring is when they do the most tree damage. The pest sucks sap from the young twigs, depriving the needles and causing them to turn a grayish green (hemlocks naturally have a shiny, dark green color).

                               Hemlocks affected by the Woolly Adelgid

Obviously, the loss of sap jeopardizes the trees' health, and within a few years of
advanced infestation, hemlocks may lose most of their needles, and can often die if
other stresses, such as drought, affect them. The insects are dispersed as they hatch in spring by wind, birds and various mammals.

These forest pests are becoming a larger problem, both in the forests and in residential stands of hemlocks. Since Pennsylvania's hemlocks prefer relatively remote locations, such as near a stream or a protected, shady locale, it is somewhat difficult to treat the trees to rid them of the pests.

The hemlock woolly adelgid, Adelges tsugae, was introduced to North America in the Pacific northwest in 1924, probably from Japan. It was first spotted on the eastern seaboard (in Virginia) in the early 50s. Defoliation due to the insect has been occurring ever since, and it is spreading.

                                      Close-up of a WA

About 35 (out of 67) counties in Pennsylvania have now confirmed the presence of this adelgid, mostly in the southern and eastern counties. The pest first appeared in Pennsylvania (in Chester County) in the mid-'60s; at the time, they were confined to ornamental hemlocks. Over the last 20 years, however, the hemlock woolly adelgid has become a significant threat to Pennsylvania's state tree.

                         Affected areas

Well I hope this article has informed you of what is happening in Penn's Woods, which are our woods. Is this devastating? Yes, but it's not the end. We can still enjoy the woods, hiking, and Geocaching.



GREAT ARTICLE BigAl! Totally an eye opener for me. I have heard about them but this piece gives me the whole picture and it isn't pretty. This whole Northeast PA area is heavily populated by Hemlocks, it's our state tree for goodness sake and this could be disastrous. Not just in PA according to the map, Connecticut, New York, Rhode Island and Massachusetts have a lot to lose as well.
Two questions:
1. Where do these critters come from?
2. Are there plans to combat these critters with pesticides and what alternate effect will that have on the region?

sarah saad said...

شركة نقل عفش بينبع
نقل العفش والتخزين
شركة نقل عفش بالمدينة المنورة

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