Influence of Abiotic and Biotic Factors on Kudzu Bug Populations in Kudzu in Eastern Tennessee

The kudzu bug, Megacopta cribraria (F.) (Hemiptera: Plataspidae), was first discovered in the U.S. in 2009. Kudzu bug feeds primarily on invasive kudzu vine (Pueraria montana Lour. (Merr.) var. lobata (Willd.) [Fabales: Fabaceae]) but has become a pest of soybeans (Glycine max (L.) Merr. [Fabales: Fabaceae]) and homes throughout the South. Previous research has shown that established populations are bivoltine, and that the second generation of kudzu bugs are problematic for soybean growers in Tennessee. Most research to date has focused on management of this pest in soybeans. Large-scale ecological factors affecting kudzu bug populations have yet to be examined in depth within kudzu. This research aims to elucidate factors that impact kudzu bug populations. Research objectives are to: 1) investigate kudzu bug populations in eastern Tennessee, 2) elucidate abiotic factors that may impact kudzu populations, and 3) assess the impact of natural enemies on kudzu bug populations. Samples were gathered in kudzu patches in six eastern Tennessee counties to assess kudzu bug populations. Factors including climactic data were analyzed for population-level impacts. Natural enemies that were investigated included the entomopathogenic fungus, Beauveria bassiana (Bals.- Criv.) Vuill (Ascomycota: Hypocreales: Cordycipitaceae), and a previously undetected egg parasitoid of kudzu bugs (Hymenoptera: Encyrtidae). Percent infection by B. bassiana was estimated in each county via sampling along within-patch transects. Kudzu clippings were also screened for endophytic B. bassiana. Egg masses were collected from six counties and parasitoids allowed to emerge. Kudzu bug population densities have diminished substantially in the last four years in eastern Tennessee. Drought, temperature, and recent precipitation were all related to kudzu bug population densities. Egg parasitoids were recovered from kudzu bug eggs from early June – late September 2017, and B. bassiana was recovered from late August – late October in both 2016 and 2017. Endophytic B. bassiana was observed in kudzu collected from all sites. The combination of these natural enemies may offer season-long biological control of M. cribraria and maintain kudzu bug populations below economically damaging levels for soybeans. This research will enhance understanding of factors driving kudzu bug population dynamics and aid in the refinement of management strategies.