Insecticidal activity of oil-in-water emulsion formulations of essential oils against white fly, Bemicia tabaci (Gennadius)(Homoptera: Aleyrodidae)

Whitefly, Bemisia tabaci (Gennadius)(Homoptera: Aleyrodidae)is one of the global polyphagous pests in many agricultural crops. Besides, other control strategies, essential oils are being considered as one of the promising candidates for developing alternative strategies for its management. We evaluated the Oil-in-water (O/W)formulations (47.6 percent)of 6-essential oils (pine oil, lemongrass oil, geranium oil, eucalyptus oil palmarosa oil and citral)against B. tabaci to determine their contact toxicity potential and phytotoxicity effects. The GC-MS analyses of test essential oils contained geraniol (69.8 percent)in palmarosa oil, ?-3-carene (50.7 percent)in pine oil, citronellal (33.4 percent)in geranium oil as major constituents. The O/W emulsion formulations were physically stable at room temperature with average droplet size of 136-425 nm. Geranium oil showed high phytotoxicity at 0.125 percent concentration in brinjal, Solanum melongena (Variety: MEBH-10)leaves, whereas, the eucalyptus and pine oils were not phytotoxic. Comparatively, palmarosa oil displayed maximum contact toxicity with LC50 and LC90 values of 0.241 and 0.658 percent respectively at 24 h and 0.142 and 0.398 percent at 48 h after exposure. This study revealed that O/W emulsion formulations of palmarosa and lemongrass oil can be effectively used in whitefly management.