Ação do extrato de folhas do nim sobre o pulgão da couve

Abstract

The neem, Azadirachta indica A. Juss is a plant that has insecticidal properties and has been used as an alternative in control of many arthropod pests. Being the aphid Myzus persicae (Sulzer, 1776) an important pest for the cultivation of kale (Brassica oleracea L. var. Acephala), action of the aqueous extract was evaluated of green neem leaves on this insect. After natural infestation of the cabbage seedlings Myzus persicae was performed by counting the number of living insects per plant: nymphs and adults, then the plants were placed in containment cages, maintained in the laboratory under temperature of 28 + 8 ° C Relative humidity of 70 + 5% and photophase of 12 hours. They were employed four treatments, with four replications. In the first treatment (T1) or control, was used only distilled water in the other, we used aqueous extract of green neem leaves the following concentrations 8%; 10% and 12%, represented by T2; T3 and T4, respectively. The mortality of aphids was assessed 24 hours after spraying, when it was found that all neem-based treatments showed significant differences compared to the control. The extracts at all concentrations tested were effective insecticide action on the control of Myzus persicae, controlling 100% of the bugs in the nymphal stage and 99.94% in adulthood. The concentrations used did not cause signs of phytotoxicity during the experiment, showing that the aqueous extract of green leaves a natural defensive potential and a viable alternative to chemical pesticides due to favorable ratio efficiency / cost to the farmers, to their low environmental impact and the contribution to human health.