The inter- and intraspecific differential responses of Frankliniella fusca and Frankliniella occidentalis (Thysanoptera: Thripidae) to systemically-applied imidacloprid and cyantraniliprole

The electrical penetration graph (EPG) technique has been used to monitor and quantify the feeding behavior of piercing-sucking insects both in the presence and absence of insecticides. Among these observed insects are several species of plant virus-vectoring, economically important thrips (Thysanoptera: Thripidae). Herein we observe the feeding behavior of two thrips species, Frankliniella fusca and Frankliniella occidentalis, both of which make up a pest complex responsible for the transmission and movement of tomato spotted wilt virus (TSWV) in various agroecosystems in the southeastern United States, on tomato plants treated with systemically-applied imidacloprid and cyantraniliprole. We couple our quantitative EPG data with the knowledge of factors conducive to the successful transmission of TSWV to generate visual representations of their feeding behavior, thereby allowing for facilitated insight into both the interspecific differential responses present between the members of this pest complex, intraspecific differential responses to two insecticides with differing modes of actions, and the putative effect of these responses on successful TSWV transmission. Interspecifically, our findings show that the feeding behavior of F. occidentalis is likely more conducive to TSWV transmission than that of F. fusca. Intraspecifically, our findings show that neither insecticide likely has an appreciable effect on disrupting F. occidentalis-vectored TSWV. Both insecticides likely disrupt F. fusca-vectored TSWV, albeit in different ways. Our findings can aid in managerial decisions against this insect-virus complex, and offer insight into how insecticides of varying chemistries function when employed as part of an integrated pest management regimen.