EFEITO INSETICIDA-FUMIGANTE DO ÓLEO ESSENCIAL DE MENTRASTO SOBRE Zabrotes subfasciatus (COLEOPTERA: CHRYSOMELIDAE: BRUCHINAE)

Naturally, plants use secondary metabolites to defend themselves from pests. This feature can be used as a sustainable alternative to replace conventional insecticides that cause biological imbalances and compromise human health, which therefore becomes a major concern. Therefore, the objective of this work was to evaluate the insecticide-fumigant activity and chemical composition of the essential oil of the weed, Ageratum conyzoides L. (Asteraceae), in the stored grain pest Zabrotes subfasciatus (Coleoptera: Chrysomelidae: Bruchinae). In the chemical characterization, by gas chromatography coupled to the mass spectrometry (GC / MS), 17 compounds were found, highlighting the peaks number 5 (2H-1-Benzopyran) and 6 (7-methoxymethyl). 2,2-dimethyl- or Precocene I) as major compounds. In the fumigation test, it presented a lethal concentration of 10,601 μL / L Ar to kill 95% (CL95) and a sublethal concentration of 2,40 μL / L Ar to kill 50% (LC50) of the population. Thus, stepfather essential oil can be used in agriculture as an ally in stored grain pest control.