From the order, Hemiptera, the hemlock woolly
adelgid, or HWA (Adelges tsugae) is an invasive species wreaking havok
on hemlock stands in the eastern United States. The nymphs of this
species (pictured below in an S.E.M.) feed on tissues of
the young twigs of the trees. This damages the tree by depriving it of
the stored starches the young tissue would provide. The HWA gets its
name from the woolly-looking substance that covers the insect and its
eggs as it matures.
Management efforts to control this pest
include selectively applying pesticides as well as introducing predatory
beetles as a biological control.
Read more: http://tinyurl.com/c5a74vz
http://www.uri.edu/ce/factsheets/sheets/hemadelgid.html
http://www.nps.gov/neri/naturescience/hwa.htm
http://en.wikipedia.org/wiki/Hemlock_woolly_adelgid
Photo: http://www.nps.gov/neri/naturescience/hwa.htm