Bioensaio da ação inseticida de folhas de nim, Azadirachta indica A. Juss sobre Myzus persicae (Sulzer, 1776)

Abstract

The neem, Azadirachta indica A. Juss, due to the presence of insecticidal substances in its leaves and fruits, has been used as an alternative in the control of numerous pests. Among the insects that affect the production of arugula (Eruca sativa Miller), the aphids of the species Myzus persicae (Sulzer, 1776) stand out because of their high reproductive capacity, high potential for economic damage and performance in virus transmission. Their control is made primarily of synthetic chemical pesticides which, when misused, can have adverse effects on the environment, man and other animals. The efficiency of the insecticidal activity of the aqueous extract of neem green leaves obtained by the manual maceration process in the 4%, 6% and 8% (w / v) concentrations was evaluated under laboratory conditions, treatment as control: water. Arugula plants (Eruca sativa) infested with nymphs and adults of aphids Myzus persicae were placed in confinement cages, after the counting of the insects in said plants. These cages were maintained in the laboratory with a temperature of 27 ± 8 ° C, 70% RH and 12-hour photophase, receiving the plants, 04 treatments, with 04 replicates. In the T1 treatment (control), only distilled water was used, while in the other T2, T3 and T4, an aqueous extract of neem green leaves was used in the concentrations 4%, 6% and 8% respectively. After 24 hours of the spraying of the extracts in the plants, it was verified that all the treatments presented significant differences in relation to the control it was observed an efficient insecticidal action, both in the nymphal phase and in the adult phase of the aphid Myzus persicae, controlling 100% the insects. The concentrations used did not provoke signs of phytotoxicity during the experiment, and the aqueous extract of neem green leaves was shown to be a natural defensive potential.