Potencial inseticida de óleos essenciais sobre Chrysodeixisincludens (Walker, 1858) (Lepidoptera: Noctuidae)

Abstract

Chrysodeixis includens (Walker, 1858) (Lepidoptera: Noctuidae), popularly known as soybean looper, is a polyphagous insect that attacks approximately 29 plant families, and in Brazil there are around 73 host species, among them grains and vegetables growing, becoming an economically important insect-plague. One of the reasons of having difficulty of control is because of its low susceptibility to synthetic chemicals. The problem worsens when it is associated with organic production systems. Plant essential oils may present insecticidal potential and present alternative methods of pest control. In this sense, the objective of this work was to evaluate the insecticidal potential of five essential oils of different species on second instar caterpillars of C. includens and to identify the main chemical compounds. The essential oils evaluated were Eugenia uniflora L.(Myrtaceae), Casearia sylvestris L. (Salicaceae), Melaleuca alternifolia C. (Myrtaceae), Pogostemon cablin B.(Lamiaceae) and Andropogon nardus L. (Poaceae). applied at the concentration of 1% on the diet of C. includens on 12-well acrylic plates (repetition), using eight replicates per treatment. The plates were conditioned in an air-conditioned room at a temperature of 27 ± 2 ° C. The evaluation was performed daily for 10 days, quantifying the number of dead insects. It was found that the oils at the 1% concentration caused the following mortalities, and presented as major compounds: E. uniflora - 32.27%, Calamen-10-one; P. cablin B. - 30.20%, Pachoulol; C. sylvestris L. - 24.48%, y-Murolene; A. nardus L. - 23.97%, B-Cironelal.