Characterization of Field-Evolved Resistance to Afidopyropen, a Novel Insecticidal Toxin Developed from Microbial Secondary Metabolites, in Bemisia tabaci

Abstract

Afidopyropen, a newly identified chemical, is a derivative of pyripyropene A, which is produced by the filamentous fungus Penicillium coprobium. It is a promising novel pesticide applied against whiteflies in agriculture. In this study, the reversion and selection, cross-resistance patterns, synergistic effects, and fitness costs of afidopyropen resistance were studied in a field-developed resistant population of B. tabaci. Compared to a reference MED-S strain, the field-developed resistant Haidian (HD) population showed 36.5-fold resistance to afidopyropen. Significant reversion of resistance to afidopyropen was found in the HD population when it was kept with no selective pressure of the insecticide. The HD-Afi strain, developed from the HD population with afidopyropen pressure, developed 104.3-fold resistance to afidopyropen and significant cross-resistance to sulfoxaflor. Piperonyl butoxide (PBO) largely inhibited afidopyropen resistance in the HD-Afi strain, which indicates that P450 monooxygenase could be involved in the resistance. Significant fitness costs associated with afidopyropen resistance were observed in HD-Afi. This study indicates that a rotation of afidopyropen with other chemical control agents could be useful for impeding afidopyropen resistance in B. tabaci. In addition, we expanded upon the understanding of resistance to afidopyropen, offering evidence suggesting the importance of devising better strategies for the management of whiteflies.

Insecticide Resistance and Its Management in Two Invasive Cryptic Species of Bemisia tabaci in China

“…Resistance selection experiments showed that resistance to afidopyropen in one strain was stably increased from the second to the sixth generation. Additionally, this resistance was subsequently stabilized between the seventh and tenth generations [ 43 ]. Thus, in contrast to abamectin, B. tabaci is expected to rapidly develop resistance to afidopyropen when exposed to this insecticide within several generations.…”

“…In an abamectin-resistant MEAM1 (B) strain, the oxidase inhibitor piperonyl butoxide (PBO) and the GST inhibitor diethyl maleate (DEM) produce significant synergistic effects on abamectin, indicating that enhanced metabolism mediated by P450 monooxygenase and GST activity, but not esterase activity, may be involved in abamectin resistance [ 40 ]. In an afidopyropen-resistant strain, PBO also showed significant synergism with afidopyropen, suggesting that oxidative metabolism may be one mechanism that results in afidopyropen resistance [ 43 ].…”

“…There was no cross-resistance between afidopyropen and pymetrozine in B. tabaci , even though these pesticides target the transient receptor potential vanilloid (TRPV) channel of insects, suggesting that afidopyropen may more effectively target the TRPV channel [ 42 ]. Furthermore, afidopyropen-resistant MED (Q) individuals showed significant cross-resistance to sulfoxaflor, but little cross-resistance to cyantraniliprole, flupyradifurone, imidacloprid, or thiamethoxam [ 43 ].…”

“…Under pesticide selection pressure, B. tabaci resistance increases at different rates, depending on the pesticide. In the absence of a pesticide, resistance declines rapidly [ 30 , 43 ]. Selection of the most appropriate chemical insecticide for a given situation should take into consideration the available officially registered products and various parameters, such as crop stage, post-harvest interval, presence of beneficial insects or pollinators, pest infestation level, presence of other coexisting pests, and pesticide resistance history.…”

“…Rational use of synergists can effectively improve the efficiency of some metabolizable insecticides; the effects of various synergists are closely related to pesticide metabolic mechanisms. PBO can play a synergistic role with numerous pesticides, such as thiamethoxam, imidacloprid, acetamiprid, cyantraniliprole, flupyradifurone, and afidopyropen [ 31 , 32 , 34 , 38 , 43 , 44 ]. This indicates that oxidases have a key role in the metabolism of many pesticides.…”