Efficiency of Various Wild Plant Extracts Against the Cotton Aphid, Aphis gossypii Glov. (Aphididae: Homoptera)

Crude extracts of wild plant species were investigated for their activity against cotton aphid, Aphis gossypii Glov. Extracts were obtained by extracting fresh plants successively with solvents of variable polarities, hexane, diethyl ether, ethyl acetate, acetone and ethanol. Among of 125 solvent extracts, hexane, diethyl ether, and ethyl acetate extracts of Hyoscyamus muticus, acetone extract of Verbascum sinuatum and ethanol extract of Rumex dentatus gave high toxicity against A. gossypii. Their LC50 values were 0.727, 0.883, 1.013, 0.805 and 1.143 mg/cm2, respectively. Results indicated that 19 plant hexane extracts induced high toxic effect (LC50 ranged between 0.727 and 7.481 mg/cm2) against A. gossypii. Also, 22 plant diethyl ether extracts showed high toxic effect towards the tested insect (LC50's ranged from 0.883 to 10.00 mg/cm2). On basis of the LC50 value, 21 plant ethyl acetate extracts exhibited potent activity to A. gossypii (LC50 values ranged between 1.013 and 10.857 mg/cm2). Twenty-two acetone extracts that revealed high toxic effect (LC50 values ranged from 0.805 to 9.377 mg/cm2) to the tested pest, also 24 tested plant ethanol extracts that exhibited potent activity to A. gossypii (LC50 values ranged between 1.143 and 8.727 mg/cm2). The ethanol plant extracts proved superior efficiency against A. gossypii followed by acetone, hexane, ethyl acetate and finally diethyl ether plant extracts.