The Impact of Hexane and Ethanol Extracts of Jatropha Seeds, Arqel Stems and Malathion on Mortality and Fecundity of Tomato Leaf Miner Tuta Absoluta (Lepidoptera: Gelechiidae)

Abstract

The effects of hexane and ethanol organic extracts of jatropha Jatropha curcas seeds, argel (Solenostemma argel (Del.) stem and malathion on mortality and fecundity of the tomato leaf miner Tuta absoluta were evaluated under laboratory conditions at a temperature of 27 ± 2c and a relative humidity of 30 ± 5%. Two-day old adults were tested against four different concentrations of each extract. The mortality results showed that all tested concentrations gave significantly higher mortality percentage than that of the control. The LC50 values of the ethanolic extract of jatropha seeds after 24, 48 and 72 hrs of exposure were 6.406, 2.278 and 2.493 respectively whereas those of the hexane extract were 6.219, 5.629 and 3.139 respectively. The results also showed that the LC50 values obtained by jatropha seeds ethanolic extracts after 48 and 72 hours were lower than their counterparts of the hexane extract which may be suggest that the active ingredient in jatropha seeds is easily extracted in ethanol rather than in hexane. The LC50 values of ethanol extracts of argel stems after 24, 48 and 72 hrs were 17.716, 8.336 and 6.860 respectively whereas those of the hexane extract were 26.191, 26.191 and 13.571 respectively. The mortality results generated by the 15% hexane and ethanol extract of both jatropha seeds were not significantly different from the standard, malathion, after 48 and 72 hrs of exposure which indicates the potency of these extracts. The results also showed that all tested concentrations of hexane and ethanol extracts of both jatropha seeds and argel stems resulted in a significantly lower fecundity of the treated insects than that of the control; however, there was no significant difference in fecundity among insects treated with different concentrations.