Impact of two formulations of the acaricide bifenazate on the spider mite predator Phytoseiulus persimilis Athias‐Henriot (Acari: Phytoseiidae)

Abstract

AbstractTwo formulations of the novel miticide bifenazate, Floramite SC (240 g/L bifenazate) and Acramite SC (480 g/L bifenazate) were separately evaluated at a rate of 310 mg a.i./L (1.3 mL/L Floramite or 0.65 mL/L Acramite) for side effects on the phytoseiid predatory mite Phytoseiulus persimilis. Tests included a combination of contact and residual treatment by overhead spray, direct contact by immersion, residual contact with treated leaf discs and repellency of a treated surface. Spray application of Acramite to protonymphs and to adult females on leaf discs did not cause increased mortality over 5 days to either stage. Oviposition by treated adults was not affected over 5 days. Egg‐laying by adult females sprayed as protonymphs was reduced, but fewer males and inadequate food supply may have been partly responsible. For adult females treated as nymphs by micro‐immersion in Floramite or Acramite, there were no significant differences between treated and untreated P. persimilis in mortality or oviposition. For both formulations, there was a significant reduction in oviposition rate of the first generation reared from eggs deposited on treated foliage, but the reduction was <20%. Foliar applications of both formulations to leaf discs were repellent to adult females, resulting in reduced oviposition. The repellency from a treated surface and low direct and indirect toxicity suggests that application of both Acramite and Floramite against two‐spotted mite, Tetranychus urticae, at the currently recommended rate of 310 mg a.i./L would be compatible with use of P. persimilis, particularly as a spot treatment.