Effects of alternative pesticides on greenhouse whitefly in protected cultivation

Abstract

The greenhouse trials were conducted to determine the efficacy of environmentally safe insecticides/fungicides with physical mode of action [Agri-50E (propylene glycol alginate, hydrated) and SB Plant Invigorator] against Trialeurodes vaporariorum (Westwood). The efficacy of Agri-50E on adults and nymphs (first, second, third, and fourth instars) was compared to the commercially available standard Boxer 200 SL (imidacloprid) and an untreated control on greenhouse-grown poinsettia. Insecticides were applied by foliar spraying, Agri-50E (2 or 3 ml/l) two times and Boxer 200 SL (1 ml/l) once. Three and 7 days after first application (DAFA), imidacloprid was more effective than both concentrations of Agri-50E in controlling T. vaporariorum adults, whereas 10 DAFA there were no differences between insecticides. Twelve DAFA, imidacloprid was more effective than Agri-50E in controlling first, second and third instars and after 19 days in controlling second, third, and fourth instars. The results obtained from the poinsettia study, indicated that Agri-50E (2 or 3 ml/l) is successful in controlling T. vaporariorum adults and moderately effective against T. vaporariorum immature stages. In the second experiment, the efficacy of Agri-50E on adults was compared to SB Plant Invigorator (SBPI), the standard treatment Calypso 480 SC (thiacloprid), and an untreated control on greenhouse-grown tomato. Agri-50E (3 ml/l) and SBPI (2 ml/l) were applied four times while Calypso 480 SC (0.4 ml/l) was applied twice. The results obtained from tomato study showed that SBPI was the most effective insecticide against T. vaporariorum adults, followed by Agri-50E and Calypso 480 EC. Beside the ecological benefits, the alternative insecticides Agri-50E and SBPI might have an important role to play in future pest management programs.