A predatory mite, Amblyseius swirskii, and plastic mulch for managing melon thrips, Thrips palmi, in vegetable crops

Abstract

Melon thrips, Thrips palmi Karny (Thysanoptera: Thripidae), is a significant pest of vegetable crops and ornamental plants due to feeding and oviposition injury to vegetative and reproductive tissues. As an integrated approach, we evaluated the efficacy of a phytoseiid mite, Amblyseius swirskii Athias-Henriot, and different colored and UV-reflective plastic mulches for managing T. palmi in snap bean (Phaseolus vulgaris L.), cucumber (Cucumis sativus L.), yellow squash (Cucurbita pepo L.), eggplant (Solanum melongena L.), Jalapeño pepper (Capsicum annuum L.), and tomato (Solanum lycopersicum L.). The five mulch treatments evaluated were: “Shine N′ Ripe” (Metalized top and black bottom), “Can-Shine” (Metalized top and white bottom), “Black” plastic black-on-black (Can-Grow-XSB), black-on-white (Can-Grow XSB), “White” plastic; white-on-black (Can-Grow XSB), and bare soil with no mulch. The number of T. palmi adults and larvae in leaf samples collected from the middle third (stratum) of plants in each treatment was determined. In 2015 at 49 days after planting (DAP), curative release of 40–50 A. swirskii per plant did not suppress T. palmi effectively when the thrips population was high. There were no significant interactions between A. swirskii and crop or A. swirskii and mulch type on the number of T. palmi. However, in 2016 at 15 DAP, preventive release of A. swirskii, reduced the number of T. palmi in each of the mulch and crop treatments. Metalized mulch reduced the number of T. palmi early in the season when plants’ canopy did not shade the mulched area. These results suggest that use of metalized reflective mulch and A. swirskii, each have the potential to manage T. palmi at low population densities.