Efeito inseticida de óleos essenciais de espécies de Piper para o controle da Plutella xylostella (L.) (Lepidoptera: Plutellidae)

Abstract

Plutella xylostella (L.) (Lepidoptera: Plutellidae), commonly known as diamondback moth, is an important pest of brassica crops, because its damage causes large losses of economic value to producers. Therefore, its control consists mainly in the use of synthetic insecticides, which can cause among others, biological imbalances. Control alternatives have been developed, among them, the use of essential oils (EO's). Essential oils of the Piper genus have been extensively researched and are promising as an alternative to synthetic insecticides for pest control. The objective of this study was to evaluate the insecticidal activity of larval and ovicidal toxicity, deterrence, repellency and phytotoxicity of Piper capitarianum and Piper krukoffii oils for the control of P. xylostella, as well as the synthetic insecticide Decis® and the commercial botanical insecticide Azamax®, for comparison purposes. The oil of P. capitarianum provided the best results in all bioassays, with CLs50 (0.21 mg mL-1) and (0.60 mg mL-1) for larval and ovicidal toxicity, respectively; IA50 of 0.70 mg mL-1, being more effective than Azamax®; repellence degree high to moderate with IR ˃ 1 in CL20 at 24 h, and mild phytotoxicity. The oil of P. krukoffii showed to be more attractive, with lower deterrent effect and less larval and ovicidal toxicity, and it could be used with bait. Essential oils seem promising but require further work to acquire more information.