Consumption of Bemisia tabaci by various guilds of generalist predators in Georgia cotton fields detected by molecular gut content analysis

Bemisia tabaci is a major polyphagous pest of several crops worldwide and has recently infested agricultural fields in Southeast USA. Given the rapid development of resistance towards major insecticides, alternative ecosystem-friendly management options are warranted. We studied available primers for B. tabaci for their sensitivity, specificity and half-life detectability for B. tabaci DNA. While all tested primers were sensitive and specific, they had considerably different detectability of half-life for B. tabaci DNA. The half-life was longer for spiders and sucking bugs with 62 and 44 h than chewing beetles with 23.5 h post-feeding. The percent of predators positive for B. tabaci within each functional group was adjusted based on their half-life weight to estimate a standardized frequency of B. tabaci predation. Several abundant predators, including Hippodamia convergens, Geocoris punctipes, Orius spp. and Thomisidae spider, tested positive for B. tabaci , with 60, 27.7, 24.4 and 19% weighted positives, respectively. In this study, for the first time, we have reported predation on B. tabaci by fire ants, Dolichopodidae flies, Coccinella septempunctata, Tetragnathidae and Oxyopidae spiders. Overall, our results provide evidence of a diverse group of predators contributing to B. tabaci suppression in the Southeast USA.