Efeito de extratos vegetais e óleos essenciais no desenvolvimento de Plutella xylostella (L.) (Lepidoptera:Plutellidae)

Abstract

The family Brassicaceae is one of the most economically important in the world, having as their main pest to Plutella xylostella (L.) (Lepidoptera: Plutellidae), which causes great damage to the crop with up to 100% of yield losses. In order to investigate alternatives to synthetic insecticides, medicinal plants have been in recent years in search of compounds with insecticidal properties, repellent, fumigant or that act directly on the disruption of biological cycles of pests such as P. xylostella. Furthermore, the literature is scarce when it comes to studies with the use of essential oils and organic extracts to verify their potential insecticide. Accordingly, the medicinal plants chosen to carry out the research potential of the insecticide are the following families: Tiliaceae (Muntingia calabura) Piperaceae (Piper marginatum) Rutaceae (Citrus reticulata x Citrus sinensis, C. reticulata Blanco) and Myrtaceae (Melaleuca leucadendron). The bioassays carried out indicated that P. xylostella larvae were susceptible to all selected plant extracts and oils tested. Furthermore the extract etanolic of flowers (MCEFL) achieved 99.5% of larvalmortality and a lethal concentration LC50 estimated of 1.63 mg/mL. In addition the extract MCEFL caused 100% of pupal inviability on treated larvae. The development of larvae increased 1.62 days when being treated with the extract hexanic of fruits (MCHFR) compared to the untreated ones. P. xylostella was susceptible to all essential oils tested. Among the oils the mosttoxic was those prepared from Citrus (LC50 of 0.55ppm for C. reticulata and 0,78ppm for C. sinensis x C. reticulata). Also, the oil from C. reticulata x C. sinensis increased larval development in 2.2 days compared to the other oils and untreated larvae.