Efeitos de formulações de inseticidas botânicos e óleos essenciais sobre a biologia e comportamento de Aphis gossypii Glover (Hemiptera : Aphididae), em algodoeiro

Abstract

The aphid, Aphis gossypii Glover (Hemiptera: Aphididae) stands out among the major cotton pests, and therefore alternative tactics have been used in its control, such as botanical insecticides. This study aimed to evaluate the lethal and sublethal effects of botanical insecticides on the biology and behavior of this pest. Experiments were performed in the laboratory using leaf discs of cotton CNPA 8H cultivar, immersed in the concentrations of formulated botanical insecticides (emulsifiable oils and extract) and essential oils as food substrate. Formulations based on neem and Bioalho® caused significant reductions in reproductive rates obtained by the life table of fertility. On the other hand, essential oils did not alter significantly these parameters except the oil of Chenopodium ambrosioides L. (Chenopodiaceae), which increased reproductive rates due to the likely hormoligosis effect. For products tested by the instantaneous rate of population growth, Compostonat®, Rotenat® and Neempro caused aphid population decline, while Natuneem promoted positive rates, indicating that the population continued to increase. Concerning the aphid behavior, repellency-choice experiments were performed. The oils of Piperaduncum L. (Piperaceae), Azadirachta indica A. Juss. (Meliaceae) and Cymbopogom winterianus (L.) (Poaceae) had the highest repellency percentage (66.67, 60.87 and 84%) for adult females.The latter two oils also reduced nymphs production (80.65 and 92%). The opposite occurred with F. vulgare, which attracted significantly aphid females to the treated disks and stimulated nymphs production.