INSECTICIDAL EFFICACY OF MINTWEED, YAM BEAN AND CELERY SEED EXTRACTS ON Aedes aegypti L.

Biological control of Aedes aegypti, the dengue virus vector, is needed to replace synthetic insecticides. This study demonstrated the insecticidal efficacy of water and ethanolic seed extracts of mintweed Hyptis suaveolens (MSE), yam bean Pachyrhizus erosus (YSE) and celery Apium graveolens (CSE) on controlling of Ae. aegypti larvae and adults. The cytotoxicity of the extracts was investigated by brine shrimp lethality assay (BSLA). Yam bean extracts were highly cytotoxic to brine shrimps. All seed ethanolic extracts were more toxic to mosquitoes than water extracts. The insecticidal efficacy of all extracts ranged as YSE/e > YSE/w > MSE/e > CSE/e > MSE/w > CSE/w. YSE/e was most toxic to Ae. aegypti 2nd instar larvae and adults with LC50 of 16.22 ± 0.20 μg/ml and 91.41 ± 0.49 μg/ml respectively and much higher than MSE/s and CSE/e. YSE in combinations produced strong synergistic effects to the other extracts. The insecticidal activities of MSE and CSE were mild. They could lessen the activity of YSE. This study demonstrates that the safe utilization of plant seed extracts, particularly of the very toxic yam bean seeds, as Ae. aegypti biological control agents are possible by either individuals or suitable combinations with other plant or seed extracts.