Efficacy of Neoseiulus longispinosus (Evans) in Controlling Spider mite on Cucumber: Laboratory and Field Studies

Abstract

Abstract The cultivation of cucumber (Cucumis sativus L.) is of great economic importance in India and is widely used in various culinary applications. However, its production is threatened by the increasing incidence of spider mite infestation. In this context, the present study evaluated the effectiveness of the predatory mite, Neoseiulus longispinosus (Evans) (Acari: Phytoseiidae), as a biological control agent against the emerging cucumber pest spider mite, Tetranychus macfarlanei Baker & Pritchard (Acari: Tetranychidae). The study involved laboratory and outdoor trials with varied predator-prey ratios of 1:25, 1:50, 1:100, and 1:200. Laboratory trials revealed that complete elimination of prey mites was achieved at 10 and 12 days after predator release at ratios of 1:25 and 1:50, respectively. Recommending ratios of 1:25 and 1:200 to the farmer was deemed uneconomical due to the negative impact on the cost of management. Field trials were conducted with the two most effective predator-prey ratios, 1:50 and 1:100, and both ratios resulted in a more than 99% reduction in the prey mite population 20 days after predator release. The study concludes that N. longispinosus is an effective and sustainable biocontrol agent for spider mites on cucumber plants. Recommending predator-prey ratios of 1:50 or 1:100 to farmers can lead to significant reductions in pest populations without incurring excessively high management costs.