ABSTRACT
The neem plant (Azadirachta indica A. Juss) possesses insecticide properties and has been used widely as an alternative in the control of a number of pest arthropods. As the aphids Brevicoryne brassicae (Linnaeus, 1758) and Myzus persicae (Sulzer, 1776) are important pests in the cultivation of kale, the present study was aimed to evaluate the efficiency of the extract of neem oil for the control of these insects. Ten adult aphids were put into Petri dishes 5 cm in diameter, containing leaf disk of kale on an agar gel layer. The insects were given the substances by means of a hand sprayer at the concentrations of 0.25%; 0.50%; 0.75%; 1.0% and 2.0%. As positive controls, 0.028% imidacloprid was utilized, while the negative control was only distilled water. The Petri dishes were maintained in an climatic chamber at 25 ± 2º C, relative humidity of 70 ± 10% and 12-hour photophase. The evaluations of mortality of the aphids and of the number of surviving nymphs from the treated adults were carried out at 1h, 6h, 12h, 24h, 48h and 72h after spraying of the compounds on the insects. Neem oil at all the tested concentrations is efficient in the control of B. brassicae, but for M. persicae it is toxic only at the concentrations of 1% and 2%.
KEY WORDS
Brassicaceae; botanic insecticide; aphids; mortality
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