Insecticidal Activity of Some Wild Plant Extracts and Plant Essential Oils Against Whitefly, Bemisia Tabaci (Genn.)

摘要

Extracts of seven plants and five plant essential oils were investigated for their toxicity against a field population of the whitefly Bemisia tabaci (Genn.). Among hexane extracts, Haplophyllum tuberculatum extract was the most effective at the LC_(50) level (0.029 mg/ml). The hexane extracts of Anthemis melanopodia and Monosonia senegalensis had not the same high effect (LC_(50), 0.053 and 0.056 mg/ml, and toxicity index 54.72 and 51.79 %, respectively). As for chloroform extracts, Silybum marianum was the most toxic to B. tabaci than those of other plants (LC_(50):0.039 mg/ml and 100 % toxicity index). The acetone extract of Polygonum equisitiforme gave the highest toxic effect (LC_(50): 0.021 mg/ml). Also, the extracts of S. marianum, H. tuberculatum and Launea spinosa gave high toxic effect against the adult stage of the insect (LC_(50) 0.121, 0.446 and 0.940 mg/ml, respectively). The ethanol extract of P. equistrforme had a high potency among seven tested ethanol extracts at Lc_(50) level. From the results, three plant hexane extracts, H. tuberculatum, A. melanopodia and M. Senegalensis, chloroform extract of S. marianum, and acetone extract of P. equistrforme were the most toxic as compared to the remaining extracts. All tested plant oils had toxic effects on the whitefly, B. tabaci adult and the oil of O. basilicum was the most toxic (LC_(50) 1.6%) followed by M. viridis (LC_(50) 2.2 %), M. hortensis (LC_(50) 2.3%) L officinalis (LC_(50) 2.5%) and M. piperita (LC_(50) 2.7%).