Biological Control of Tetranychus Urticae (Tetranychidae) On Rosebushes Using Neoseiulus Californicus (Phytoseiidae) And Agrochemical Selectivity

The two-spotted spider mite, Tetranychus urticae (Tetranychidae), is an important pest in rosebush (Rosa spp.), currently controlled by using agrochemicals. Phytoseiidae mites are used for biological control of pest mites. This study aimed to evaluate the biological control of the T. urticae on rosebushes grown in greenhouse after releases of the predatory mite Neoseiulus californicus (Phytoseiidae). In addition, the selectivity of some agrochemicals for disease and mite control was tested. Three experiments were conducted in a completely randomized design using potted roses. Twenty females per plant of the two-spotted spider mite were placed for infestation. After nine days, 0 to 14 predatory mites per plant were released. After 15 days a new release was made in one of the experiments. Predation was assessed one month after release by randomly collecting rosebush leaves from the apical, medial and basal regions, and the number of living T. urticae was counted. Selectivity was studied by using the laboratory method of residue spraying on a glass surface. Products were sprayed in a Potter tower with the highest doses recommended for the products. The number of live females and eggs laid by the predatory mite were evaluated. It was concluded that N. californicus is efficient in controlling the T. urticae under greenhouse conditions. The mineral oil, acephate, tebuconazole, iprodione, fenpropathrin and abamectin showed to be slightly harmful to the predator and could be used for integrated control. On the other hand, fenpyroximate was highly toxic to the predator mite.