Parental exposure of tea tree ( Melaleuca alternifolia ) essential oil on offspring demographic traits in the rice moth, Corcyra cephalonica

Abstract The rice moth, Corcyra cephalonica (Lepidoptera: Pyralidae) is a dominant species infesting stored grains that feeds on a wide variety of hosts. Currently, there is increasing emphasis on using plant essential oils for sustainable crop protection. Hence, the current study was conducted to characterise tea tree ( Melaleuca alternifolia ) essential oil followed by its contact and fumigant toxicity across generations against C. cephalonica . Oil extraction was carried out by the hydro‐distillation method and subjected to chemical profiling through gas chromatography mass spectrometry analysis. The chemical constituents 1,8‐cineol (67.79%), α‐pinene (16.73%) and α‐terpinol (4.87%) were the major components of essential oil responsible for toxicity against insects. From contact toxicity bioassay, it was observed that tea tree oil exhibited 86.67% mortality, whereas 70% mortality was observed in the case of fumigant toxicity. Lethal and sublethal doses obtained from contact toxicity bioassay were applied to C. cephalonica larvae to study generational effects on their biological as well as population traits. The results demonstrated that the individuals of two subsequent generations of test insects have a lower net reproductive rate ( R 0 ) and gross reproductive rate when exposed to LC 30 and LC 50 as compared to control. Reduction in adult fecundity and longevity was also observed for both generations for these two doses. Overall, the present study is useful in providing important knowledge regarding the lethal and sublethal toxicity of the essential oil on C . cephalonica larvae for their management and also, leveraging for mass rearing of natural enemies on C. cephalonica as a factitious host.