Precision and accuracy of field versus bioassay insecticide efficacy for the control of immature Bemisia tabaci

Authors: CREMONEZ, PAULO - University Of Georgia; PERIER, JERMAINE - University Of Georgia; NAGAOKA, MIRELA - University Of Georgia; Simmons, Alvin; RILEY, DAVID - University Of Georgia

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/16/2023
Publication Date: 7/17/2023
Citation: Cremonez, P.S., Perier, J.D., Nagaoka, M.M., Simmons, A.M., Riley, D.G. 2023. Precision and accuracy of field versus bioassay insecticide efficacy for the control of immature Bemisia tabaci. Insects. 14:645. https://doi.org/10.3390/insects14070645.
DOI: https://doi.org/10.3390/insects14070645

Interpretive Summary: It is important to have precise and accurate information when assessing insecticide resistance in pest populations. The sweetpotato whitefly was used as a model for developing a tool for assessing insect resistance for insect pests on crops. Laboratory assays were found to be more precise in measuring insecticide efficacy compared with field assays, and seasonal variations indicate the importance of identifying and considering external factors when estimating insecticide efficacy or predicting the status of the field response of pests to insecticides. This information will be useful for researchers and pest management profession.

Technical Abstract: Ecotoxicological studies often result in reports on the limitation and sometime failures of biological assay data to predict field response to similar treatments. Nevertheless, it is widely accepted that controlled bioassays can better quantify the specific mortality response of a target pest species to a specific toxin. To quantify the relationship between laboratory bioassays and field response data, we evaluated a controlled laboratory assay and a concomitant cucurbit field trial method to assess insecticide efficacy for controlling the sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae); data were based on oviposition and nymphal development. We specifically tested the assumptions that a maximum dose bioassay would more precisely measure insecticide efficacy than a comparable field spray test evaluation and that the response would be equal between the laboratory bioassay and the field as a measure of control accuracy for both adult oviposition and development of the nymphal stages. To make a direct comparison, we tested the same whitefly population subsamples from 352 plots in eight cucurbit field experiments in Georgia, USA, in 2021 and 2022. Laboratory assays are significantly precise in estimating proportional whitefly response. As expected, treatment-specific nonequivalence in immature counts between the bioassay and field, i.e., a lack of accuracy, only occurred with insecticides that were not highly toxic to all growth stages of whiteflies.