Inseticidas nas sementes e a entomotoxina cry 1 ac protegem a soja contra a lagarta-do-velho-mundo

Abstract

The Helicoverpa armigera caterpillar occurs from the emergence of the plants to the reproductive stage of the soybean crop, which can cause significant losses.As an initial pest, both neonate and more developed caterpillars can be found, the latter from the previous crop.The use of Bt cultivars and insecticides in seed treatment are options to pest managementat the beginning of soybean development, but there are doubtsabout the efficacy of these control methods. Thus, the objective was to evaluate the protective effect of insecticides applied to seeds and Cry 1Ac protein, in relation to the attack of the H. armigeracaterpillar, as an initial pest in soybean plants.Experiments were conducted in the laboratory, using a completely randomized design, with six treatments:four insecticides related to seeds and control (without insecticide), in conventional cultivar soybeans (Target BMX), and the Cry 1Ac protein in soybeans cultivate Bt (DM 5958 IPRO), without insecticide. Our results confirm that under laboratory conditions the insecticides cyantraniliprole (60 g ai / 100 kg of seeds) and chlorantraniliprole (62.5 g ai / 100 kg of seeds) protect the soybean against the injuries of H. armigera3º-4ºínstars, in cotyledons and unifoliolate and trifoliolate leaves, at 5 days after the emergenceof the plants. The protein Cry 1Acprotects the soybean plants from this type of injury caused byboth3rd-4thand 5th-6thínstarscaterpillars, at 5 and 10 days after emergence.