Aquatic Plant Management and The Impact of Emerging Herbicide Resistance Issues

Abstract

Aquatic plants provide many benefits to the environment, but must be managed when growth reaches nuisance levels or when invasive plant species are released. Management tactics include biological, chemical, cultural, mechanical, and physical tools. Each specific management technique has advantages and disadvantages. In addition, the implementation of these techniques can become complicated because of the multiple users, managers, and stakeholders that may be present on large bodies of water. As an example, hydrilla is the most economically damaging aquatic weed in the United States. It reproduces through fragmentation, turions, and occasionally seed and can colonize a wide variety of aquatic environments. The most common management tactics for hydrilla include biological, chemical, and mechanical tools. Triploid grass carp have been the primary biological control agent, whereas fluridone has been the only systemic herbicide used. Because of heavy utilization of fluridone, biotypes have developed resistance to this herbicide in Florida. Although several acetolactate synthase-inhibiting herbicides are in development, herbicides with additional modes of action are needed for resistance management. Other aquatic plant management needs include additional control tactics for algae and additional extension resources for public education.Nomenclature: Fluridone, hydrilla, Hydrilla verticillata (L.f.) Royle, triploid grass carp, Ctenopharyngodon idella Val