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Title: Organic duckweed management with pelargonic acid

item Webber Iii, Charles

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/5/2009
Publication Date: 10/15/2009
Citation: Webber III, C.L. 2009. Organic duckweed management with pelargonic acid [abstract]. Third National Conference on Agriculture & Natural Resources Conservation & Management, October 15-18, 2009, Dover, Deleware. p. 28.

Interpretive Summary:

Technical Abstract: Duckweed (Lemna spp.) are small, free floating aquatic plants that flourish on stagnant or slow moving water surfaces throughout the continental U.S. They are among the smallest flowering plants, providing food for fish and fowl, but their aggressive growth and invasive tendencies make them formidable aquatic weeds which uncontrolled can result in oxygen depletion, fish kills, and death of submerged aquatic plants. Greenhouse research was conducted at Lane, OK to determine the feasibility of using pelargonic acid to control duckweed. Pelargonic acid is a fatty acid naturally occurring in many plants and animals, and present in many foods we consume. AU720 (65% pelargonic acid, BioSafe Systems LLC) is a potential organic herbicide under development for aquatic weed control. Treatments included 4 dilutions of the product (0.0006%, 0.0015%, 0.006%, and 0.015% v/v) and a control (0% v/v) with 8 replications and the experiment was repeated twice. Duckweed (7.5 g) was added to 400 mL beakers containing 250 mL of the diluted solutions and the beakers placed in the greenhouse. Visual ratings were collected 1, 3, and 5 days after treatment. Pelargonic acid was phytotoxic at all dilutions. Duckweed control was less than acceptable (less than 10% control) at 0.0006% and 0.0015%, inconsistent at 0.006% (3 to 99% control), but very affective (96 to 100% control) at 0.015%. These preliminary studies demonstrated that pelargonic acid (AU720) has potential as a duckweed management tool, if used at 0.015% v/v.