THE BIOLOGY OF CANADIAN WEEDS.: 88. Elodea canadensis Michx.

Abstract

A review is provided of information on the biology of elodea (Elodea canadensis Michx.). This submersed aquatic develops dense beds that impede water traffic and restrict water-based recreation in the southern portions of Quebec, Ontario, in British Columbia and Alberta. In some regions the dense beds decrease the efficiency of irrigated agriculture. Native to North America, elodea has recently spread to other parts of the world including Europe, Asia, South Africa, Australia and New Zealand. Elodea is beneficial in providing food and cover for insects and other small aquatic organisms, and consequently it increases food availability for fish and ducks. It also has some potential as a source of food and forage because of its relatively high nutritional content. Elodea is most frequent in clear, nutrient-rich, alkaline water. Phosphorus levels in the plant have been utilized as an indication of trends in the nutrient enrichment of water bodies. Limiting nutrients include bicarbonate and iron. Although seed formation is rare, dispersal of overwintering dormant apices and stem fragments by water and by waterfowl can result in rapid spread. Mechanical controls, including boats equipped with cutters, are the preferred methods of managing elodea, but adequate harvesting of cut material is necessary because every fragment with an axillary or terminal bud may develop into a new plant. Biological control using nonreproductive plant-eating fish is a promising area of research.Key words: Elodea canadensis, weed biology, aquatic, Canada, distribution