Effect of some micro and nanoemulsified essential oils and plant extract on sweet potato whitefly, Bemisia tabaci (Gennadius), under laboratory condition

One of the most important pests of agricultural crops is sweet potato whitefly, Bemisia tabaci. Although some essential oils and plant extracts have shown suitable insecticidal properties against this pest, because of considering the high volatility and instability of essential oils, application of these substances for pests control is not practically and commercially possible. In this study, essential oils of Rosmarinus officinalis, Mentha piperita and Eucalyptus globules and extract of Thymus vulgaris, formulated based on micro and nano-emulsion and their insecticidal efficiency and stability was tetted agianst B. tabaci in laboratory condition. Bioassay was carried out by leaf dip method on second instar nymphs and LC50, LC90, and LT50 values were determined. Also, alive second instar nymphs to alive adults conversion ratio and fecundity in treated insect were determined as sublethal effects and compared with Palizin® vegetable soap, distilled water and control (without treatment). The results showed that nano-emulsion treatment containing all tested essential oils was the most efficaciouswith LC50=0.7454 mg/l, LC90=3.1208 mg/l, and LT50=15.92 h. Also, alive second instar nymphs conversion ratio to alive adults in this treatment was 80% and the mean number of eggs was 191.33 that was most efficacious. Afterwards, microemulsion treatment containing essential oils and extract had a acceptable effect. These two treatments were known as promising compounds in integrated management of this pest and further testing is required for commercialization of these compounds.