Controle do pulgão verde com extrato foliar de nim

Abstract

Neem, Azadirachta indica (A. Juss) has insecticidal properties distributed by the constituents of the plant that is used as an alternative in the control of several different pests. As one of the pests that cause damage to the culture of the Lettuce (Lactuca sativa L.), the aphid Myzus persicae (Sulzer, 1776) is a pest that presents high severity due to its fast reproduction and transmission of viruses. The action of the green leaf aqueous extract of neem on this insect was evaluated. After the natural infestation of lettuce seedlings by Myzus persicae, the number of live insects per plant was counted: nymphs and adults, then the plants were placed in confinement cages, kept in laboratory under 28 + 8 ºC temperature. Relative Humidity 70 + 5% and 12 hour Photophase. Four treatments were used with four repetitions. In the first treatment (T1) or control, only distilled water was used; in the others, aqueous extract of green neem leaves was used at the following dilutions 4%; 6% and 8%, represented by T2; T3 and T4, respectively. The aphid mortality was evaluated 24 hours after spraying, when it was found that all neem-based treatments showed significant difference in relation to the control. The extracts in all evaluated dilutions had an efficient insecticidal action to control Myzus persicae, controlling 100% of the insects in the nymphal phase and 100% in the adult phase. The dilutions used did not cause any signs of phytotoxicity during the experiment, showing that the aqueous extract of green leaves is a natural defensive potential and a viable alternative to chemical pesticides due to the favorable efficiency / cost ratio for the rural producer. environmental impact and pose no risk to human health.