Utilização de extrato pirolenhoso e nim sobre a oviposição da traça das crucíferas

Abstract

The diamondback moth (Plutella xylostella) is the main pest of brassicas, causing damage to several species of economic importance. Plutella xylostella interferes with productivity of these crops, as well as the attractiveness and commercial value of the products, generating significant economic impacts for producers. The control of this insect is mainly done by chemical products, however, they are products with high commercial value and offer risks mainly to the environment and human health, making it necessary studies that aim at alternative methods for pest control. In this context, the objective of this work was to evaluate the oviposition inhibitory effect of the species Plutella xylostella in cabbage. Two experiments were carried out, both in a completely randomized design with 15 replications. In the first experiment, the treatments used were concentrations 0; 0.5; 1.0; 2.0; 3.0; and 4% pyroligneous extract. In the second experiment, the treatments were the dose of 1.5% of Azadirachta indica and distilled water. The kale leaf discs were immersed for five seconds in these concentrations and after drying they were offered with a choice to 60 non-sexed adults of P. xylostella for oviposition. For six days, every 24 hours the discs were replaced and the number of eggs was counted. The number of total eggs of the insect in leaf discs of cabbage was evaluated. The doses of pyroligneous liquor applied on kale leaf discs did not inhibit the oviposition of adults of Plutella xylostella. Azadirachta indica applied at 1.5% produced a suppressive effect on the oviposition of P. xylostella in kale leaf discs.