Insights on mitigation, fumigant persistence and oviposition deterrence of Callosobruchus chinensis using Ocimum gratissimum essential oil

Abstract

An increased human population rate has advanced the need to manage production and shelf life of food grains. Significant loss of food grains by insect pests has led to the overuse of chemical pesticides for their management. The present study focuses for an alternative to synthetic pesticides, a natural derived insecticidal biorational from Ocimum gratissimum (O. gratissimum) essential oil (EO) against Callosobruchus chinensis (C. chinensis) which is a notable pest responsible for quantitative and qualitative loss of stored pulses. The EO obtained from unique Ocimum chemotype contains thymol (26.67%), gamma terpinene (19.98%) and o-cymene (13.54%). The insecticidal toxicities (fumigant and contact) of EO showed significant death rate (100%) of C. chinensis at 24 h. Additionally, EO concentrations with 10%–50% showed good oviposition deterrence of C. chinensis. SEM analysis of EO treated C. chinensis exhibited disintegrated setae on elytral surface. Besides, treated grains has revealed no significant residual persistence of aroma and retained germination. Hence, O. gratissimum EO might be a potential biorational entrant for the effective control of C. chinensis.