Direct and indirect effects of selective insecticides on two generalist predators of Bemisia tabaci (Hemiptera: Aleyrodidae)

Authors: PARKINS, ALBERTHA - University Of Georgia; KHEIRODIN, ARASH - Texas A&M University; PERIER, JERMAINE - University Of Georgia; CREMONEZ, PAULO S. - University Of Georgia; PAULO, DAVID - University Of Georgia; Simmons, Alvin; SCHMIDT, JASON - University Of Georgia

Submitted to: BioControl
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/22/2024
Publication Date: 11/1/2024
Citation: Parkins, A.J., Kheirodin, A., Perier, J., Cremonez, P.G., Paulo, D.G., Simmons, A.M., Schmidt, J.M. 2024. Direct and indirect effects of selective insecticides on two generalist predators of Bemisia tabaci (Hemiptera: Aleyrodidae). BioControl. 24(6): 1; ieae104. https://doi.org/10.1093/jisesa/ieae104.
DOI: https://doi.org/10.1093/jisesa/ieae104

Interpretive Summary: Arthropod predators serve an important role in helping to control agricultural pests. When insecticides are used in crop production, it is quite useful that the insecticides do not harm the predators. A study was conducted to assess the impact of two commercial insecticides (Cyantraniliprole and Pyriproxyfen) on the populations of two predators (convergent lady beetle and big-eyed bug) on whitefly infested plants. Overall, pyriproxyfen had a minimal negative impact on survival and feeding by the predators, while cyantraniliprole had a big adverse impact on the predators. The results from this study will be useful for the agricultural community to develop and implement improved management strategies for whiteflies and other pests.

Technical Abstract: Generalist arthropod predators have historically contributed to the suppression of arthropod pests in many agroecosystems. The successful implementation of Integrated Pest Management (IPM) programs hinges on the incorporation of insecticide that is compatible with the biological attributes of natural enemies of pests. A potentially promising pathway is improving biological control by natural enemies through the timely application of selective insecticides. However, knowledge gaps persist regarding sublethal impacts on natural enemies despite the potential benefits. In our study, adult predators were exposed to commercially available insecticides (Cyantraniliprole and Pyriproxyfen) using a combined laboratory and field approach to assess their effects on survivorship and predation. We isolated two predators, Hippodamia convergens Guérin-Méneville (Coleoptera: Coccinellidae) and Geocoris punctipes (Hemiptera: Geocoridae), in the laboratory to estimate survivorship and consumption of whitefly nymph, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). In the field, we deployed whitefly-infested potted cotton plants in replicated cotton plots with various insecticide treatments. We enumerated whitefly populations on enclosed (predator-exclusion) and open (predator-accessible) potted plants. While pyriproxyfen had a negligible effect on the predators, cyantraniliprole exposure directly affected H. convergence by reducing survivorship duration and indirectly influenced both predators by reducing prey consumption and altering prey preference. In field conditions, regardless of pesticide exposure, whitefly-infested potted plants that excluded predators had more whiteflies than predator-accessible potted plants. Overall, pyriproxyfen demonstrated minimal impact on the predators in the laboratory or field, while cyantraniliprole adversely influenced morality and indirect foraging under controlled laboratory conditions, but did not have a significant impact in the field.