Amblyseius largoensis (Acari: Phytoseiidae) is a cosmopolitan species and a common predator inhabiting citrus orchards and other fruit crops in Florida. It has been reported as an efficient biological control agent of citrus leprosis mite Brevipalpus yothersi (Acari: Tenuipalpidae). For the success of IPM, it is imperative to determine the selectivity of acaricides to predatory mites. We studied the ecological selectivity of four acaricides to A. largoensis: abamectin, cyflumetofen, fenpyroximate, and spirodiclofen. The survival and fecundity of A. largoensis were assessed following acaricide administration via different routes: residual contact, direct contact, pesticide-laced prey (B. yothersi), or a combination of pesticide-laced prey, residual and direct contact. The survival and fecundity of A. largoensis were significantly affected by the route of exposure. The fecundity of A. largoensis was significantly reduced when the different exposure routes were combined compared to each exposure route alone. Selectivity of abamectin and spirodiclofen was relatively high for all the exposure routes. Cyflumetofen showed the lowest selectivity via direct and residual contact. Fenpyroximate showed low selectivity via direct contact, acaricide-laced prey and combined exposure routes. However, the selectivity of fenpyroximate via residual contact was high. Our results show that the selectivity of the tested acaricides to A. largoensis can be enhanced by restricting exposure to a single route.
