Potential push-pull cropping approach for pickleworm (Diaphania nitidalis) management in Hawaii

Historically pickleworm, Diaphania nitidalis Cramer (Lepidoptera: Crambidae), has been a major pest in the southeastern United States, though over the past decade it has become a pest in Hawaiian cucurbit production. In Hawaii, growers rely heavily on insecticide sprays for pickleworm management. However this practice is unsustainable due to the increased likelihood of insecticide resistance, and its negative impact on bees, which pollinate cucurbits. This study investigated the potential of a push-pull cropping approach to manage pickleworm on cantaloupe (Cucumis melo L.). Seven locally relevant squash varieties (Cucurbita pepo L.) were evaluated to be a potential trap crop (pull) based on their relative attractiveness as an egg-laying site. Three watermelon varieties (Citrullus lanatus [Thunb.] Matsum. & Nakai) were assessed as possible deterrent intercrops (push) based on oviposition preference. Finally the relative oviposition preference of three cantaloupe varieties was investigated to determine if there are any inherent differences in the attractiveness among cantaloupe varieties. The results suggest that female moths have no strong oviposition preference among varieties within each plant species. This implying that any of the seven squash varieties could be appropriate as a potential trap crop, likewise all of the cantaloupe and watermelon varieties should function equally well in this cropping system. In addition to oviposition preference, a larval host plant preference study was conducted with naïve neonate larvae and larvae that had experience feeding on a particular diet. Results indicate that larval feeding experience does influence larval diet preference. The implications of this will be discussed.