Efficacy of <em>Eucalyptus citriodora</em> and <em>Syzygium aromaticum</em> essential oil as insecticidal, antiovipositant, and fumigant against <em>Callosobruchus maculatus</em> F (Coleoptera: Bruchidae)

Abstract

Callosobruchus maculatus is the most pernicious pest of stored grain worldwide. Even though synthetic insecticides are commonly used to eliminate this insect pest, the negative effect of this pest management method on humans and the environment raises concern among people around the world. This study was done to identify the active ingredient of essential oils in Eucalyptus citriodora and Syzygium aromaticum and to evaluate the effectiveness of those essential oils in controlling C. maculatus. The results of gas chromatography/mass spectrometry analysis indicated that the essential oil extracted from the leaves of S. aromaticum are rich in Eugenol and β caryophyllene as much as 81% and 14.65% consecutively, while E. citriodora oil contains 86% of Citronella. According to the bioassay results, increasing the essential oil concentration from 1% to 3% resulted in a significant increase in insect mortality rate, oviposition deterrence, and fumigant toxicity. Additionally, S. aromaticum has significantly shown a higher insecticidal performance compared to E. citriodora. However, there are no synergistic effects observed on the use of essential oil of both plant species on C. maculatus. These results suggest that S. aromaticum and E. citriodora essential oils could be potential candidates as a natural insecticide in managing C. maculatus in stored products.