Preston, Carrie E.Arneson, AliciaSeiler, John R.Salom, Scott M.2023-04-122023-04-122023-03-29Preston, C.E.; Arneson, A.; Seiler, J.R.; Salom, S.M. The Impact of Predation of Laricobius nigrinus (Coleoptera: Derodontidae) on Adelges tsugae (Hemiptera: Adelgidae) and Tsuga canadensis (Pinales: Pinaceae) Tree Health. Forests 2023, 14, 698.http://hdl.handle.net/10919/114490The hemlock woolly adelgid (HWA), <i>Adelges tsugae</i>, has threatened the sustainable management of <i>Tsuga canadensis</i> in the eastern United States. Biological control efforts have led to the establishment of <i>Laricobius nigrinus</i>, a specialist predator of HWA. Although <i>L. nigrinus</i> has a significant impact on HWA populations, its effect on the health of HWA&rsquo;s host is unknown. In 2020, 14 eastern hemlocks at one site in Virginia were selected to determine whether predation of <i>L. nigrinus</i> at different densities on HWA populations had an effect on tree health. <i>Laricobius nigrinus</i> predation significantly impacted the HWA sistens generation, resulting in significantly more new shoots produced on treatment branches with the greatest density of <i>L. nigrinus</i> adults. Final HWA density was lowest on treatment branches with <i>L. nigrinus</i>, followed by the negative control, and the treatment without <i>L. nigrinus</i>. In June, the photosynthetic rate was significantly greater for the negative control, followed by <i>L. nigrinus</i> treatments. There were no statistical differences among measured tree physiological parameters in July and October, indicating a temporary effect from <i>L. nigrinus</i> predation on hemlock tree physiology.application/pdfenCreative Commons Attribution 4.0 Internationalclassical biological controlhemlock woolly adelgideastern hemlockphotosynthesisLaricobius nigrinusArticle - Refereed2023-04-12https://doi.org/10.3390/f14040698