Control of the emerging aquatic weed Amazon frogbit with flumioxazin

Abstract

Amazon frogbit is an emerging aquatic weed that causes significant impacts to freshwater systems in Australia. Currently there are limited control options available, with only one herbicide (flumioxazin) registered for its control. Outdoor pond trials demonstrated that foliar and subsurface flumioxazin application provide excellent Amazon frogbit control (95-100% biomass reduction) at intermediate label rates. Subsurface application provided slightly better control than foliar spray. However, in deeper waterbodies foliar application will be more economical. In a field trial, a subsurface injection of flumioxazin (200 ppb) in a farm dam covered by a dense Amazon frogbit infestation provided ~99% control with a single application within three months. Overall, our work demonstrated that flumioxazin is an excellent control tool to manage Amazon frogbit and will greatly enhance the management of this invasive aquatic weed.