Insect biology and host fruit volatiles can influence the efficacy of novel attract and kill (ACTTRA SWD) formulations against Drosophila suzukii

In the continental United States, the invasive insect, spotted-wing drosophila, Drosophila suzukii Matsumura, has become a primary pest of multiple stone and soft-skinned fruits. A new innovative adjuvant formulation, ACTTRA SWD, mixed with a suitable insecticide, constitutes a novel attract-and-kill tactic to manage D. suzukii in fruit crops. We hypothesized that background odors present in crop fields, particularly odors from host fruits, negatively affect the effectiveness of this attract-and-kill formulation, as odors from these sources can compete for insect attraction. Additionally, we evaluated the influence of adult D. suzukii physiological status on its response to the ACTTRA SWD formulation. For this, we used two-choice bioassays to test the response of adult D. suzukii to two ACTTRA SWD formulations (named OR1 and TD) in the presence and absence of host fruits (blueberries, raspberries, blackberries, and strawberries). We also tested the effects of sex, age, and mating status on D. suzukii attraction to the two ACTTRA SWD formulations. Results from this study show that odors from raspberries were significantly more attractive than those from the ACTTRA SWD TD formulation. For the ACTTRA SWD OR1 formulation, odors from both raspberries and blackberries were significantly more attractive than the adjuvant. Compared with females, males D. suzukii were more attracted to the ACTTRA SWD TD formulation over the blueberry fruits. The results from this study will improve our understanding on how D. suzukii physiological status and host fruit availability impact the efficacy of new attract-and-kill adjuvants such as ACTTRA SWD.