Assessing New Tools for Management of the Pepper Weevil (Coleoptera: Curculionidae) in Greenhouse and Field Pepper Crops

The pepper weevil, Anthonomus eugenii Cano, is an economically important pest of field and greenhouse pepper crops in North America. In this study, a series of insecticides covering a broad-spectrum of insecticidal modes of action were assessed for their potential in managing the pepper weevil under laboratory and greenhouse conditions. To accomplish this, laboratory mini-spray tower and greenhouse cage trials were conducted that evaluated the efficacy of 16 conventional, reduced-risk, and microbial insecticides. In laboratory trials, adult weevils were sprayed with insecticides, placed on treated leaves within a cup cage, and were monitored for their survival over 10 d. Of the 16 insecticides tested, 8 provided greater than 60% weevil control, a threshold considered necessary for including products in further greenhouse testing. In greenhouse trials, adult weevil mortality, bud and foliar damage, bud and fruit abortion, and subsequent weevil offspring emergence were measured following each of three weekly insecticide applications. The most efficacious insecticides included kaolin clay and mineral oil, which performed as well as the thiamethoxam-positive control, and incurred 70 and 55% of adult weevil mortality, respectively. Additionally, kaolin clay and mineral oil reduced offspring weevil emergence by 59 and 54%, respectively, compared with untreated controls. Despite the clear challenge that controlling this pest represents, this study has identified useful new tools for the integrated management of the pepper weevil, which may accelerate the rate at which these become available for use in greenhouse and field pepper production.