Predation by Neoseiulus cucumeris and Amblyseius swirskii on Thrips palmi and Frankliniella schultzei on cucumber

Abstract

Thrips palmi Karny and Frankliniella schultzei Trybom (Thysanoptera: Thripidae) are serious pests of various crops of economic importance across the globe. Two species of phytoseiid mites were evaluated as potential predators of T. palmi and F. schultzei in the laboratory, a shade house and a commercial cucumber production field. In a no-choice lab bioassay, both Amblyseius swirskii (Athias-Henriot) and Neoseiulus cucumeris Oudemans (Mesostigmata: Phytoseiidae) preyed in equal measure on larvae of T. palmi and F. schultzei placed on leaf disks. In the shade house, mites were only recovered from leaf samples and not in flowers. Consequently, they were only effective in controlling T. palmi on leaves. Two rates of mites (20 and 40 mites/plant) were tested in the field. Neither species nor rate suppressed F. schultzei in blooms. In contrast, both rates of A. swirskii suppressed T. palmi on leaves, although the high rate acted more rapidly and therefore had a greater overall effect over the course of the 22-day study. These results suggest that A. swirskii can serve as an effective alternative to conventional insecticide-based management of T. palmi in commercial open field cucumber production in Florida.