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Abstract plant species belonging to family Euphorbiaceae were investigated for their feeding deterrent effect, stomach poison, contact effect and biological effects on further development of larvae of Spodoptera littoralls (Boisd.). The plant species investigated were :- (1) Euphorbia pulohrrima (Willd). (2) Phyllanthus nivosus ~ atropurpureus (Bull). (3) Euphorbia laetea (How.). (4) Euphorbia aphylla (Brouss). In the first plant leaves, stems and flowe~s were used and in the second one leaves and stems were used. The other plants, aerial parts were examined as a whole. The dry powder of pl.antorgans were prepared and extraoted with the following solvents successively 1.e. ethanol, acetone, chloroform, petroleum ether and distilled water respectively. Castor leaves were treated by impregnation with the extracts and introduoed to fourth instar larvae of oatton leaf worm the peroentage of reduotion in feeding of, treated leaves Was determined compared to leaves treated With the solvent alone as control. The results showed that petroleum ether leaf extracts of Phyllanthus nivoBus var atropurpureuB produoed the maximum feeding deterrence. Extracts were tested for their contact effect by topical application to fourth inetar larvae. Mortality was recorded after 24 and 48 hours. Results revealed that the chloroform extract of the stems of Euphorbia ]ulchrrima was the most effective. The fact that chloroform on ita own produced considerable mortalities shed some doubt on the result. Further detailed studies on this extract are needed. Some extracts were investigated for their biological effect on the development of 6 is instar larvae and results showed that petroleum ether extract of the leaves of Euphorbia pUlchrrima caused maximum adverse effects on development when it was topically applied to 6 ib inatar larvae of Spodoptera littoralis. However, no juvenoid-like effects were noticed. The adverse effects were confined to small percentages of mortalities, deformities in later stages and little depression in fertility among females. Preliminary phytochemical screening was carried out and showed that petroleum ether extract of leaves of Fhyllanthus nivoBus ~ atropurpureus whioh showed feeding deterrenoe had only one group; terpenes. Acetone extract of the above-mentioned plant organ contained several phytochemical groups i.e glycosides, flavonoids, alkaloids and saponins. A trial to separate these groups was carried out by column chromatography and the different fractions were eValuated by bioassay. Results showed that the most effective fractions were separated by elution with chloroform and ethanol. Phytochemical teste were run for these fractions and sh~Jed that chloroform separated saponins and alkaloids and ethanol separated glycosides and flavonoids. from the results and by comparison of the reduction percentages in feeding in the crude extract and in the fractions mentioned above, it Was concluded that the crude extract act s through a combinat ion of all these components. Qualitative chemical tests of the petroleum ether extract of the leaves of Euphorbia Eulcbrrima revealed that it contained flavonoids, glycosides and terpenes. The active material may be one or all these components. |