Performance of the lady beetle Eriopis connexa to sequential exposure to selective insecticides prevailed over its pyrethroid resistance.

Conservation biological control techniques support integrated pest management (IPM) and insecticide resistance management (IRM) by restraining pest resurgence and outbreaks of secondary pests. The lady beetle Eriopis connexa (Germar) (Coleoptera: Coccinellidae) is among the natural enemies in agricultural systems of brassica crops and their populations may be disrupted by exposure to insecticides. Pyrethroid-resistant and pyrethroid-susceptible E. connexa larvae and adults were exposed to eight insecticides (cyantraniliprole, chlorantraniliprole, chlorfenapyr, deltamethrin, spinosad, spiromesifen, methomyl, and pymetrozine) that target different pests of brassica crops. Evaluations were conducted on larval and adult survival, larval developmental time, fecundity and egg viability across 30 days, and consumption of Lipaphis pseudobrassicae (Davis) (Hemiptera: Aphididae) or larvae of Plutella xylostella (L.) (Lepidoptera: Plutellidae) during the exposure to the insecticides. In addition, the levels of aphids and diamondback moths infestation in field cages were evaluated as a function of insecticide application and release of the lady beetles. Neither survival of larvae and adult beetles, nor fecundity, were affected by the insecticides. Surviving lady beetles from pyrethroid-resistant and pyrethroid-susceptible populations consumed aphids and diamondback moth larvae when exposed simultaneous to the insecticides targeting these pest species. There was no additive effect of the control of these pests when lady beetles were used alone or with insecticides. The findings showed the compatibility of this natural enemy with selected insecticides through multiple exposures targeting different pest species combining different insecticide modes of action. [ABSTRACT FROM AUTHOR]