Biological control of whiteflies and western flower thrips in greenhouse sweet peppers with the phytoseiid predatory mite Amblyseius swirskii Athiashenriot (Acari: Phytoseiidae).

Abstract

Currently, western flower thrips (Frankliniella occidentalis) is controlled in greenhouse sweet peppers with the phytoseiid predatory mite Amblyseius cucumeris, the anthocorid flower bug Orius laevigatus and the phytoseiid mite Iphiseius degenerans. Whiteflies (Trialeurodes vaporariorum and Bemisia tabaci are controlled by releasing parasitoids and mirid bugs (Miridae). Cage trials and trials in commercial greenhouse crops with the phytoseiid predatory mite Amblyseius swirskii (Athias-Henriot, 1962) have shown a high efficacy against Frankliniella occidentalis and against Bemisia tabaci in sweet peppers. When the predatory mites were released preventively on flowering sweet pepper plants in a greenhouse in the Netherlands the establishment of Amblyseius swirskii was successful. In all trials Amblyseius swirskii has shown a very high numerical response to the presence of prey. Biological control of whiteflies with phytoseiid predatory mites, which can be economically reared in large quantities, might be a major step forwards for biological control in greenhouse crops, especially in areas with high whitefly and thrips populations such as Southern Europe. INTRODUCTION The greenhouse whitefly, Trialeurodes vaporariorum, and the tobacco whitefly, Bemisia tabaci, are major pests in greenhouse crops. In commercial greenhouses whiteflies are mainly controlled by releases of the parasitoids Encarsia formosa and Eretmocerus eremicus against T. vaporariorum and Eretmocerus mundus against B. tabaci. Whitefly parasitoids are not able to establish in a greenhouse when released preventively. Mirid bugs (Miridae) such as Macrolophus caliginosus Wagner are expensive and their use is limited to greenhouse tomatoes. Therefore, a biological control agent which is able to establish in a crop before whiteflies enter the greenhouse would be a supplement to the system.