EFFECT OF SULPHUR FERTILIZATION ON IBERIS AMARA PLANT AND ITS INSECTICIDAL ACTIVITY

The effect of different types of sulphur on growth and chemical constituents of Iberis amara was studied for two successive seasons (2003 2004). The insecticidal activity of different extracts of /. amara on cabbage aphid was investigated. Ammonium sulphate increased plant height and flowers fresh and dry weight as compared to both potassium and sulphur. Ammonium sulphate at 120 kg S ha 1 led to increase suckers number, herb fresh weight, seed yield per increase plant, the highest contents of carbohydrate (13.95%, 14.0%) and fixed oils (13.62%, and 12.85%) for the first and second seasons, respectively and also highest contents of glucosinolates and phenolic compounds, while cucurbitacins showed a maximum with treatment of 90 kg S ha^1 ammonium sulphate. The highest concentration of ethanol extract induced the highest mortality for cabbage aphid (66.67% mortality after 96 hr), followed by Water extract after autolysis and chloroform extracts, both of which induced 53.33% mortality at the highest concentrations tested, hexane extract showed the least effect on target insect.