Óleos essenciais para o controle de Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae) e Tetranychus urticae Koch (Acari: Tetranychidae)

Abstract

Given the problems caused by the indiscriminate use of synthetic products, essential oils are an alternative for use in pest management. The objective of this study is to investigate whether binary mixtures of essential oils of Piper aduncum (PA), Melaleuca leucadendron (ML), Lippia sidoides (LS) and Schinus terebinthifolius (ST) leaves and green (SV) and ripe (SM) fruits of S. terebinthifolius potentiate their effects on Plutella xylostella (L.) (Lepidoptera: Plutellidae) and Tetranychus urticae Kock (Acari: Tetranychidae). About P. xylostella, residual and feeding deterrence action, Premio® insecticide (positive control) was more toxic (LC50=0.001μL/mL and DC50=0.0026μL/mL). Among the oils, PA showed a higher residual toxicity and deterrent (LC50=0.31μL/mL and DC50=1.08μL/mL). Toxicity and deterrence of the individual constituents indicated as the most active Dilapiol and Carvacrol (LC50=1.01μL/mL and DC50=0.075μL/mL). Among mixtures, PA+LS (50-50%) and PA+LS (25-75%) were the most toxic (LC50=3.93 and 4.48μL/mL, respectively), while PA+LS (25-75%) proved to be the most deterrent (DC50=3.23μL/mL). Synergistic effect was obtained only by residual action by LS+ST (75-25%). About T. urticae, eugenol e Vertimec® 18 EC (positive controls), were the most toxic by fumigation and residual (LC50=0.003μL/L air and 0.0006μL/mL, respectively). Among the mixtures, the most fumigantes were ML+PA (50-50%) and PA+SM (50-50%) (LC50=0.15 and 0.23μL/L air, respectively), while ML+SM (50-50%) promoted greater residual effect (LC50=6.95μL/mL). No mixture revealed synergism, being additive only ML+SM (50-50%) by residual action. The action of oils/mixtures on fecundity of T. urticae was also discussed. All oils were considered slightly harmful to Neoseiulus californicus by fumigation, while the residual action revealed harmless oils. Tests in a greenhouse indicated that after 72h, ML+SM (50-50%) promoted the same toxicity of synthetic acaricide. These results suggest that mixtures of essential oils may enhance its effects, being good candidates for use in formulations in the integrated management of P. xylostella and T. urticae.