Potencial inseticida dos óleos essenciais das espécies de Mentha para o controle de Plutella xylostella (L.) (Lepidoptera: Plutellidae)

Abstract

Use of synthetic insecticides remains the main tactic used to control agricultural pests. Small growers, such as cabbage producers of agricultural areas of Pernambuco, use synthetic insecticides as the main way to solve their problems with insect pests. However improper use results in a high number of insecticide sprays, resulting in undesirable side effects such as, the natural biological control depression, incease of the production cost, developing of insect resistance to pesticides, among others. Diamondback moth (L.) (Lepidoptera: Plutellidae) is the main pest of the family Brassicaceae, and the insect which has the highest reported cases of resistance to synthetic insecticides, so that spraying of such products has shown inefficiency. The need to develop new chemicals for pest control has increased the development of researchs with botanical insecticides. Essential oils of the species Mentha arvensis L., Mentha piperita L. and Mentha spicata (L.) has shown insecticidal activity against a wide variety of arthropods, causing repellent, ovicidal, larvicidal, and feeding deterrent effects and still affecting biological parameters to such organisms. The oils of Mentha species showed an interesting insecticidal action against 3rd-instar larvae of DBM producing DL50 lower the que Azamax, a synthetic insecticide of plant origin. However the insecticides Premio® 200 SC and Decis® 25 EC, had a lower DL50 all oils. The spraying of oils over the eggs inhibited the emergence of P. xylostella. The exhibition of DBM larvae to sublethal doses of the Mentha species oils caused effects on biological parameters, affecting the percentage of pupation, pupal weight, viability of eggs, larval survival and viability of offspring.