The predatory mite Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseidae) is a key biological control agent of the spider mite pest Tetranychus urticae Koch (Acari: Tetranychidae) and can be vulnerable to IPM practices that involve acaricide application.
This study investigated the selectivity of three classical acaricides, bifenazate, cyflumetofen, fenbutatin oxide, and two botanicals, Prev-Am and Requiem, towards P. persimilis via a direct application, an acaricide-laced diet, and a combination of direct contact, diet, and residual contact. RNA was isolated, Illumina sequenced, and the transcriptome of P. persimilis was assembled to shed light on the molecular mechanism behind the acaricide selectivity towards P. persimilis. The transcript levels were estimated to pinpoint the transcriptomic changes resulting from oral exposure to sub-lethal doses of fenbutatin oxide and Prev-Am. Subsequently, transcript read information was reviewed in search for well-known acaricide-target-site mutations. Selectivity of botanical acaricides was low but may be improved by limiting P. persimilis exposure to a single route. Differential gene expression analysis did not show a robust induced stress response after sub-lethal exposure. However, several acaricide target-site mutations have been identified, explaining the physiological selectivity of some classical acaricide classes. Less...