Efficacy of essential oils of Lippia alba (Mill.) N.E. Brown and Callistemon lanceolatus (Sm.) Sweet and their major constituents on mortality, oviposition and feeding behaviour of pulse beetle, Callosobruchus chinensis L.

BACKGROUND: Pulse beetle, Callosobruchus chinensis L., is the most destructive insect pest of pulses under storage in Asia and Africa. Keeping in view the negative impacts of synthetic insecticides and the demands of botanical pesticides, the present investigation explores the repellents, antifeedants, ovicidal, larvicidal and pupaecidal activity of two plant essential oils (EOs) and their major components, geranial and 1,8-cineole, when applied as fumigants for the management of the pulse beetle.
RESULTS: EO of Callistemon lanceolatus (Sm.) Sweet caused 100% repellency of pulse beetle in a Y-shaped olfactometer at a dose of 150 µL, while Lippia alba (Mill.) N.E. Brown EO and 1,8-cineole showed 76 and 74.7% repellency at the same dose. At 0.1 µL mL(-1) , both the oils and 1,8-cineole provided 100% insect mortality. The EO of C. lanceolatus was recorded as the most effective fumigant, showing 96.03% oviposition deterrency and 100% antifeedant activity at 0.1 µL mL(-1) . The LD(50) of L. alba (11049.2 µL kg(-1) ) and C. lanceolatus (14 626.3 µL kg(-1) ) exhibited their favourable safety profiles when recorded on mice.
CONCLUSION: EOs of L. alba and C. lanceolatus exhibited significant biological activity on the mortality and reproductive behaviour of pulse beetle. Based on their high LD(50) values, the oils could be safely recommended as non-mammalian toxic fumigants in management strategies for pulse beetle.