Impact of Syzygium aromaticum (L.) essential oil as fumigant against Tribolium castaneum (Coleoptera: Tenebrionidae)
Bhuwan Bhaskar Mishra, SP Tripathi and CPM Tripathi
Use of synthetic chemicals is a great hazard for the environment and consumers. In the present study, essential oil from buds of Syzygium aromaticum was isolated by hydro-distillation methods and tested their insecticidal activity against Tribolium castaneum (Herbst). The results showed that the essential oil of S. aromaticum have fumigant toxicity, oviposition and developmental inhibitory activity against T. castaneum. The percentage mortality increased with increasing exposure time and concentration. The median lethal concentration (LC50) of S. aromaticum essential oil at 48 h was 13.871 and 15.551 µl against larvae and adults of T. castaneum, respectively. The essential oil significantly reduced oviposition (F3,20=303.983) in adults and also reduced pupation (F3,20=54.716) and adult emergence (F3,20=101.309) in larvae when fumigated with sub-lethal concentration. The per cent grains infection was reduced 54.69% at 60% of sub-lethal concentration of 24 h LC50. Fumigation of insect with sub-lethal concentration of S. aromaticum essential oil inhibited AChE activity. Reduction in AChE activity was 9.32.48 and 10.93% of the control, after 24 h of fumigation with sub-lethal concentration. In conclusion, this essential oil probably induces toxicity in insect by inhibiting AChE activity.