Efficacy of Ocimum tenuiflorum essential oil as grain protectant against coleopteran beetle, infesting stored pulses.

In the present investigation, essential oil (EO) of
Ocimum tenuiflorum and its principal constituent (eugenol)
was evaluated for its toxicity and mode of action against
Callosobruchus maculatus. Furthermore, fumigant toxicity
and germination studies on the application of O. tenuiflorum EO and eugenol against C. maculatus on different
pulses was also studied. Fumigant activity studies revealed
that EO toxicity was significantly (p \0.05) influenced by
concentration and exposure time. In fumigant toxicity
assay without food, O. tenuiflorum EO and eugenol showed
LC50 value of 278.6 and 256.5 lL/L air, respectively, at
one hour exposure. Further, O. tenuiflorum EO displayed
fumigant toxicity via inhibiting acetylcholinesterase
activity. Pulses treated with O. tenuiflorum EO showed
70% of C. maculatus mortality at 250 lL/L air concentration after 24 h. Furthermore, these treatments didn’t
affect the seed viability of the pulses tested. Hence, the
application of O. tenuiflorum EO has potential scope as a
botanical insecticide.