INVESTIGATION OF THE INSECTICIDE POTENTIAL OF Melaleuca leucadendra ESSENTIAL OILS ON Plutella xylostella

Abstract

Plutella xylostella is one of the most important pests of agricultural interest, its damage can cause total crop loss. Currently, their control has been carried out by highly toxic synthetic insecticides, and through their continuous use has promoted the emergence of resistant populations.Studies of products derived from plant matrices, such as essential oils (OEs) show low toxicity to non-target organisms and the environment, awake interest of researchers as an alternative source to synthetic insecticides. Melaleuca leucadendra, characterized by the high production of essential oils, are reported as antimicrobial, fungicide and acaricide, and emerges as a candidate for pest control. The OEs obtained from leaves and fruits of M. leucadendra by hydrodistillation showed yielded of the 0.30±0.02% and 0.18±0.01%, respectively. GC-MS analysis of the OEs revealed a predominance of the sesquiterpene (E)-nerolidol in both leaves (95,49%±1,32) and fruits(92,06%±0,45). The insecticide potential on P. xylostella of the OEs and (E)-nerolidol isolated by column chromatography was performed by larvicidal and embryocidal toxicity bioassays. Leaf OEs (LC50 = 0,17 mg/mL), fruits (LC50 = 0,15 mg/mL) and (E)-nerolidol (LC50 = 0,18 mg/mL) revealed similar toxicities to P. xylostella larvae. On the other hand, OEs of the fruit (LC50 = 0.28 mg/mL) and leaves (LC50 = 0.23 mg/mL) were more toxic to eggs of P. xylostella than (E)-nerolidol (LC50 = 0.66 mg/mL). Comparing the results obtained for OEs and (E)-nerolidol with the commercial insecticide Azamax®, it was observed that both OEs and (E)-nerolidol showed higher toxicity to larvae and eggs of P. xylostella than Azamax® (LC50-lalvas = 2.75 mg/mL; LC50-eggs = 2.57 mg/mL).