Predation rates of commercially available Neoseiulus cucumeris and Amblyseius swirskii on familiar and unfamiliar prey in strawberry

In Florida, strawberries are prone to infestation by Tetranychus urticae Koch (twospotted spider mite). Management of these pests using conventional miticides is becoming difficult, thereby forcing many growers to adopt the use of mass reared commercially available biological control agents especially Neoseiulus cucumeris Oudemans and Amblyseius swirskii Athias-Henriot. Nonetheless, these predators are mass reared on prey different from T. urticae, and their prey switching capacity is unknown. Therefore, the objective of this study was to compare the predation rates of A. swirskii and N. cucumeris feeding on familiar and unfamiliar prey. Thus, a no choice test was conducted where A. swirskii and N. cucumeris were each provided with the familiar prey mite Acarus spp., and compared with egg, deutonymphs, and adult females of T. urticae as prey. Prey consumption was recorded at 12, 24, 36 and 48 hours. Our results show that both A. swirskii and N. cucumeris exhibited higher prey consumption when prey was familiar (Acarus spp.) compared to unfamiliar prey. In 12 hours, both predators had consumed 50% of eggs, however, 36 to 48 hours were required for 50% of the T. urticae adults and nymphs to be consumed. Therefore, strawberry growers utilizing these predatory mites ought to refrain from the use of insecticides known to be detrimental to predatory mites for a period of at least 48 hours to allow the predators to adjust to the new prey and environment.