Summary of Native and Established Predators of the Hemlock Woolly Adelgid and the Balsam Woolly Adelgid (Homoptera: Adelgidae) in the Southeastern United States

There has been little research conducted on the effects of native or established predators on populations of the hemlock woolly adelgid, Adelges tsugae Annand, or the balsam woolly adelid, A. piceae Ratz. This paper reviews what is known about the native and established predators of both species in the southeast. Field surveys and cage exclusion experiments were used to examine the relationship between established predators and A. tsugae. Predators were collected in very low densities. Harmonia axyridis Pallas (Coleoptera: Coccinellidae), lacewings (Neuroptera: Chrysopidae and Hemerobiidae), and gall gnats (Diptera: Cecidomyiidae) represented 81% of the total predators collected in 1998. Cage exclusion experiments revealed no significant predator effects in all study sites. It is unlikely that established predators are exhibiting any significant control on hemlock woolly adelgid populations because of the low densities of predators that were encountered at a time when adelgids were abundant. While similar studies of the predators of balsam woolly adelgid have not been conducted, it is clear that predators have had little impact on this adelgid.