Horowitz, M., Division of Weed Research, Agricultural Research Organization, Newe Ya'ar Experimental Station, Haifa, Israel
Givelberg, A., Division of Weed Research, Agricultural Research Organization, Newe Ya'ar Experimental Station, Haifa, Israel

Six surfactants used as additives to pesticide sprays, were applied in aqueous solution to the roots of sorghum plants. After a few hours of exposure to the surfactant solution, ions and amino‐acids leaked from the roots into the ambient solution, presumably due to a loss of membrane integrity. After 2‐3 days, the plants wilted and, at high concentrations of surfactants, they died. Toxic effects varied with the surfactant and its concentration, but no clear relationship was found between the physical effect of lowering the surface tension, the release of solutes by the roots, and the injury caused to the plant. The results are of significance because of the proposed use of sewage effluents, known to contain detergents, for irrigation purposes in Israel. Copyright © 1979 John Wiley & Sons, Ltd