Long-term weather variability and shifting distribution limits of the invasive hemlock woolly adelgid (Adelges tsugae Annand)This article is part of a larger document. View the larger document here.
The hemlock woolly adelgid (HWA) is a small, aphid-like piercing-sucking insect native to Asia and northwestern North America (Havill et al. 2006, 2007). First documented in 1951 in the eastern United States near Richmond, VA, the HWA has spread to infest at least 17 states along the Appalachian Mountains from Georgia to southern Maine, where infestations have been limited to coastal regions with more moderate temperatures. Currently, the northern regions of Vermont, New Hampshire, and Maine remain uninfested.