Exploring the efficacy of Ambylseius swirskii as a potential biocontrol agent against whiteflies in different varieties of tomato

Bemisia tabaci is a notorious pest of vegetable crops and a major pest in the tomato production system. Although insecticides were historically the primary method of control, whiteflies rapidly evolved resistance.  Research efforts are exploring alternatives, such as resistant varieties and maximization of biological control. This experiment aims to explore the potential of predatory mite Ambylseius swirskii as a biological control agent of whiteflies and assess the efficacy of tomato lines with high acylsugar content on whitefly management. The study was conducted in an organic field in which a factorial design of tomato variety and biological control were arranged in a randomized complete block design (n = 4). Tomato varieties consisted of two commercial and two experimental acylsugar lines, while the biological control consisted of the application of predatory mites at different positions on tomato plants (i.e. top, bottom, sachet, and no mite control). Treatments were applied a week after transplanting tomato seedlings and weekly samplings of predatory mites, natural enemies, and whiteflies were conducted for 6 weeks. Results indicate no significant effect of mite application on whitefly populations. Notably, we recovered few mites on any sample date (9 mites recovered out of ~8800 mites applied to the plants). However, whiteflies were significantly affected by the tomato varieties, with the lowest populations observed on acylsugar tomato lines. Despite the lower population of whiteflies, higher level of Tomato Yellow Leaf Curl Virus were observed on acylsugar tomato lines, suggesting that acylsugar lines successfully decreased the whitefly populations but not the disease.