The Use of Controlled-Release Fluridone Fibers for Control of Hydrilla (Hydrilla verticillata)

Abstract

A fiber system for controlled delivery of fluridone {1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone} was evaluated for its potential use in the management of the submersed aquatic weed hydrilla [Hydrilla verticillata(L.f.) Royle # HYLLI] in slow-moving water. The release of fluridone from the fibers was first order and could be extended over several days simply by using fibers of larger diameters. Fibers of 0.8- and 1.2-mm diam released fluridone over a period of 40 and 50 days, respectively. Both effectively controlled hydrilla at a rate of 2.2 kg ai/ha in a 4-month study in replicated pools with water flow adjusted to provide one volume change every 24 h. Under the same conditions, the conventional liquid formulation was ineffective and a pellet formulation provided only marginal control.