Aquatic Plant Control Research Program. Allelopathic Aquatic Plants for Aquatic Plant Management: A Feasibility Study

Use of allelopathic terrestrial plants has received attention in agriculture as a weed management strategy. Putnam 1983 achieved success with annual rotation of allelopathic crops or companion plantings of allelopathic and perennial crops. He was able to suppress up to 95 of several important weeds. Allelopathic aquatic plants may provide a management system for undesirable aquatic vegetation. Replacement of an undesirable species by a desirable one as a long-term, site-specific method of aquatic plant management was suggested over 30 years ago. This report presents results of a literature search and feasibility study of the use of allelopathic aquatic plants for aquatic plant management. To establish a list of potential allelopathic plants, 16 aquatic macrophytes native to the southeastern United States were subjected to two bioassays -- one involving lettuce seedlings and one involving the aquatic plant Lemna minor as the target species. The results suggest that Nymphaea odorata and Brasenia schreberi are both highly inhibitory and are therefore candidates for aquatic weed management. The results also indicate that the simple lettuce seedling assay may be a reasonable first easy assay for determining the allelopathic potential of aquatic plants. Keywords Aquatic weed control Allelopathy Aquatic macrophytes Bioassay Biocontrol Growth inhibition.