How plant and insect host characteristics affect pepper weevil Anthonomus eugenii parasitism efficacy by the pteromalid Jaliscoa hunteri

The pepper weevil Anthonomus eugenii (Cano) (Coleoptera: Curculionidae) is an economically important pest of both field and greenhouse pepper crops, Capsicum annuum Linnaeus (Solanaceae) in North America. Among its natural enemies is the parasitoid wasp Jaliscoa (= Catolaccus ) hunteri (Crawford) (Hymenoptera: Pteromalidae), whose potential control of A. eugenii appears promising but is currently unclear. We conducted controlled environment trials to quantify A. eugenii offspring emergence following exposure to J. hunteri , examining how parasitoid exposure period, weevil host life stage, pepper cultivar, fruit size and abscission status affect weevil-natural enemy dynamics. In pepper cultivar comparison trials, we identified a significant reduction in weevil offspring emergence from three different cultivars of ornamental peppers infested by A. eugenii , but no difference among them. In trials comparing wasp exposure period and weevil larval instar, pepper plants of one cultivar (Blaze) were exposed to A. eugenii adults, and subsequently to J. hunteri wasps for either three or seven days, when offspring weevils were either at the L1 or L3 instar. Offspring emergence was significantly reduced up to 62% when L3 but not L1 weevils were exposed to wasps for 7 days. Following this longer exposure period, significantly greater weevil suppression occurred in small (71.7%) versus large fruit (62.5%), with an additional 15.1% weevil suppression resulting from attached relative to abscised fruit. These results highlight the potential for J. hunteri as a biological control agent of A. eugenii on pepper crops, with particular value in commercial greenhouse production where wasp retention rates can be high.