Skip to Main Content
Assessing an integrated biological and chemical control strategy for managing hemlock woolly adelgid in southern Appalachian forestsAuthor(s): Kenton L. Sumpter; Tom J. McAvoy; Carlyle C. Brewster; Albert E. Mayfield; Scott M. Salom
Source: Forest Ecology and Management
Publication Series: Scientific Journal (JRNL)
Station: Southern Research Station
View PDF (603.0 KB)
DescriptionIn the eastern United States, hemlock woolly adelgid (HWA), Adelges tsugae Annand (Hemiptera: Adelgidae) is considered an invasive pest of eastern hemlocks; an ecologically foundational tree species. Current management of HWA focuses on chemical and biological controls, with recent research suggesting that these two tactics could be integrated successfully. The approach is
to protect a subset of hemlocks with systemic insecticides while releasing predatory insects onto adjacent, unprotected trees. The goal of this study was to assess the eﬀects of chemical and biological control tactics, alone and in combination, on hemlock health and HWA densities at three southern Appalachian sites (KY, WV, and TN) from 2010 to 2016. Although insecticide applications were effective at protecting individual trees, none of the overall treatments (chemical, biological, or combined) had a signiﬁcant eﬀect on tree health or HWA population index values relative to untreated plots. Tree health generally declined at all sites over time. HWA populations were highly variable over time and were likely more strongly inﬂuenced by extremely low, winter temperatures than by the treatments. Cross-correlation analysis of tree health and HWA population indicated a time-lag eﬀect. At two of the three sites, recovery of tree health lagged 0 – 3 years behind decline in HWA population, and decline in HWA populations lagged approximately 0 – 1 years behind decline in tree health. The predatory beetle, Laricobius nigrinus, was recovered two-years, post- release at the KY and WV sites in 2012 and 2013, but was not recovered from the TN site. The lack of sustained recovery of L. nigrinus may be attributable to the occurrence of extremely low, winter temperatures in 2014 and
2015, which produced subsequent crashes in the HWA populations. In TN, the L. nigrinus population may have been unrecoverable due to a decline in the HWA population shortly after initial release.
- You may send email to firstname.lastname@example.org to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationSumpter, Kenton L.; McAvoy, Tom J.; Brewster, Carlyle C.; Mayfield, Albert E.; Salom, Scott M. 2018. Assessing an integrated biological and chemical control strategy for managing hemlock woolly adelgid in southern Appalachian forests. Forest Ecology and Management. 411: 12-19. https://doi.org/10.1016/j.foreco.2018.01.018.
KeywordsAdelges tsugae, Laricobius nigrinus, IPM, Forest health, HWA, Imidacloprid, Biological control, Eastern hemlock, Tsuga canadensis
- Hemlock declines rapidly with hemlock woolly adelgid infestation: impacts on the carbon cycle of the Southern Appalachian forests
- Early regeneration following the presalvage cutting of hemlock from hemlock-dominated stands
- Effects of the removal of overstory hemlock from hemlock-dominated forests on eastern redback salamanders
XML: View XML