Effect of fumigation and toxicity of some essential oils on whitefly

Abstract

The present study aimed to control Bemisia tabaci through suitable successful Integrated Pest Management programs (IPMs) safe enough to man and environment, by inserting some plant oils as alternatives or synergists for pesticides. Three essential oils (Marjoram Origanum, Mentha spicata and Ocimum basilicum) extracted from Lamiaceae family were examined for their contact and fumigant toxicity against Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) under laboratory conditions during Oct. 2021. To determine fumigant toxicity, adult whiteflies were tested in airtight glass jars containing essential oil on filter paper. Mortality rates were recorded after 24, 48, and 72 h of exposure, at different concentrations (1.5, 3 and 5 ppm) of all essential oils . Essential oil from Marjoram Origanum plants was the strongest fumigant action among the tested oils, with mortality rates of 57.33%, 64.00%, and 72.00%, at concentration of 1.5 ppm, 66.67%, 74.67%, and 83.33%, at concentration of 3 ppm and 76.67%, 85.33%, and 95.33%, at concentration of 5 ppm, respectively. Mortality rates in the control were 0.0% at three ranged from 24, 48, and 72 h of exposure respectively, followed by essential oil of Mentha spicata causing mortality rates ranging from 57.33%, 64.00%, and 72.00%, at concentration of 1.5 ppm, 66.67%, 74.67%, and 83.33%, at concentration of 3 ppm and 76.67%, 85.33%, and 95.33%, at concentration of 5 ppm, respectively. essential oil of Ocimum basilicum had the third highest toxicity level which causing mortality rates of 52.00%, 58.00%, and 65.33%, at concentration of 1.5 ppm, 62.00%, 69.33%, and 78.00%, at concentration of 3 ppm and 72.67%, 81.33%, and 90.67%, at concentration of 5 ppm, respectively. Mortality rates in the control were 0.0% at three ranged from 24, 48, and 72 h of exposure with all three essential oils. The adult mortality was increased in conjunction with increasing dose of tested oils. Lethal concentrations (LC50) of all plant extracts were also estimated with serial dilutions of the plant extracts. For aqueous extracts, those of Marjoram origanum, Mentha spicata and Ocimum basilicum, however, clear from the obtained results shown that Marjoram origanum oil was the most potent against whitefly adults with LC50 value of 0.538 ppm, followed by Mentha spicata oil with LC50 value of 0.580 ppm and Ocimum basilicum oil with LC50 values of 0.631 ppm, after 72 hr, of all three oils, respectively. Conclusion: It is concluded that the tested oils may use as insecticide alternatives in an integrated pest management program for the subject pest.