Influência da aplicação de inseticidas no desenvolvimento, sobrevivência e crescimento populacional de Orius insidiosus (Say, 1832) (Hemiptera: Anthocoridae) em laboratório

Abstract

Among the natural enemies of pests that occur in tomato crop, bugs of the genus Orius are excellent predators of both eggs and small larvae of Lepidoptera, being considered biological control agents. The aim of this work was to evaluate the effect of the insecticides abamectin, cartap, spirotetramat + imidacloprid, flubendiamide, pymetrozine, pyriproxyfen and rynaxypyr on eggs of Orius insidiosus (Say, 1832) in laboratory. The experiment was conducted at the Laboratory of Selectivity of UFLA. Stems of Bidens pilosa L. containing the eggs of O. insidiosus were immersed in the chemical products aqueous solutions for five seconds. The length of the embryonic period and daily nymphs hatching were evaluated. Nymphs from treated eggs were individually placed in Petri dishes, where they received Anagasta kuehniella eggs. The nymph survival and duration of the nymphal stage were evaluated. The products were grouped in classes of toxicity based on IOBC. The reproductive capacity of O. insidiosus from treated eggs was assessed only for treatments in which it was possible to form five or more couples. To the couples it was given daily a B. pilosa stem. It was evaluated every 24 hours the number of eggs and survival of adults. It was evaluated every 24 hours the number of eggs and the adult survival. Abamectin, cartap, flubendimiade and spirotetramat + imidacloprid affected negatively the embryonic and nymphal periods of O. insidiosus (class 4). Pyriproxyfen and rynaxypyr were categorized as class 1 and pymetrozine as class 2, which was possible to form survival and fertility curves. These insecticides affected early nymphal instars of O. insidiosus, but the survival and fertility curve were similar when compared to control. The life table parameters were only negatively affected by the insecticide pyriproxyfen. The critical stage of mortality to the control treatment was first nymph and to pyriproxyfen was the first and third instars nymph. Rynaxypyr and pymetrozine did not have a critical stage of mortality of O. insidiosus. Therefore, rynaxypyr and pymetrozine can be recommended in IPM in tomato crop as a strategy for preservation of this natural enemy. Pyriproxyfen despite being selective to O. insidiosus, affected the life table parameters and further studies should be performed. Abamectin, cartap, spirotetramat + imidacloprid and flubendiamide negatively affected O. insidiosus and caused sublethal effects to nymphs and adults of the predator and, therefore, are considered toxic and should be tested in greenhouse and field conditions, to confirm or not their toxicity to O. insidiosus.