Toxicity, ovipositional behaviour and electrophysiological response of rice moth Corcyra cephalonica (Stainton) adults to essential oils

Rice moth Corcyra cephalonica (Stainton) is a serious pest on storage commodities. The management of C. cephalonica relies on the use of chemical pesticides. Insecticide resistance and its effect on nontarget demand for compounds that are clean, and green. Essential oils (EOs) viz., Trachyspermum ammi (Ajowan), Piper betle (betel), Eucalyptus citriodora (citridora), Cymbopogan nardus (citronella), Pelargoniumgraveolens (geranium), Rosmarinus officinalis (rosemary) and Ocimum basilicum (sweet basil) were investigated for their cidal activities against the egg and adult stages of C. cephalonica. On ovicidal action, among the EOs tested P. betle was found to have higher cidal action to eggs (EC₅₀ 3.79 mg/ dm³), followed by T. ammi EO (EC₅₀ 4.17 mg/ dm³). P. graveolens and P. betle EOs caused the highest fumigant toxicity in adults with the lowest LC₅₀ values (12.58 and 18.01 mg/ dm³). All the EOs tested caused an antennal response in C.cephalonica female adults. Among the Eos, R. officinalis and P. graveolens elicited the highest antennal response in female moths (1.3 mV and 0.84 mV). In the behavioural assay, the female moths showed reduced preference for the oviposition substrate treated with EOs. The desirable cidal, physiological and behavioural response of EOs on C. cephalonica adults makes them a viable alternative to synthetic pesticides.