Aquatic plants continue to create problems associated with navigation, flood control, agriculture, irrigation and drainage, values of lands, conservation of wildlife and fisheries, and water resource supply. While much research is being done to find more effective and economic control measures, there is now a great need to apply known facts to achieve a measure of control by the means available. It is the purpose of this volume to provide a scientifically documented treatise of the known facts as they apply to the control of aquatic weeds in river basins and their allied waterways with particular emphasis on alligator weed and water hyacinth.