Abstract
The cotton whitefly, Bemisia tabaci (Gennadius) is a devastating polyphagous insect pest worldwide and has been shown to be resistant to insecticides in most chemical classes. The newly commercialized pyropene insecticide afidopyropen provided a new tool to control B. tabaci because of high selectivity and its novel mode of action. This study aimed to evaluate the susceptibility of B. tabaci Asia I from ten provinces of India to afidopyropen and other commonly used insecticides. Most field-collected populations were susceptible to afidopyropen, with LC50 values varying from 4.37 to 16.62 mg L−1. However, four field populations (W-MH, K-UP, M-WB and L-PN) exhibited moderate levels of resistance (28.53, 19.09, 35.27 and 30.81-fold, respectively), but no cross-resistance to cyantraniliprole and pymetrozine. Diethyl maleate (DEM) significantly restored the susceptibility of W-MH, M-WB and L-PN strains of B. tabaci to afidopyropen, whereas piperonyl butoxide (PBO) significantly inhibited afidopyropen resistance in K-UP, M-WB and L-PN populations. The activities of glutathione S-transferase (GST) and P450 monooxygenase increased in the afidopyropen-resistant field strains, while esterase activity did not change significantly. The present study showed a regional variation in afidopyropen toxicities among B. tabaci Asia I populations from different agro-climatic zones of India, which suggests a potential risk of afidopyropen resistance development. Metabolic detoxification mediated by GST and P450 monooxygenase was associated with afidopyropen resistance in B. tabaci Asia I.
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•First report of afidopyropen resistance in Bemisia tabaci Asia I.•Four field-strains exhibited moderate level of resistance.•No cross-resistance of afidopyropen with cyantraniliprole or pymetrozine.•Elevated GST and P450 activities in afidopyropen-resistant populations.