Abstract
Additional active ingredients are needed for use in aquatic systems in order to respond to new threats or treatment scenarios, enhance selectivity, reduce use rates, and to mitigate the risk of herbicide-resistance. Florpyrauxifen-benzyl is a new synthetic auxin developed for use as an aquatic herbicide. A study was conducted at North Carolina State University, in which 10 µg L−1 of 25% radiolabeled florpyrauxifen-benzyl was applied to the isolated shoot tissue of ten different aquatic plant species in order to elucidate absorption and translocation patterns in these species. Extremely high levels of shoot absorption were observed for all species and uptake was rapid. Highest shoot absorptions were observed for crested floatingheart [Nymphoides cristata (Roxb.) Kuntze] (A192 =20 µg g−1), dioecious hydrilla [Hydrilla verticillata (L.f.) Royle] (A192 =25.3 µg g−1), variable watermilfoil (Myriophyllum heterophylum Michx.) (A192 =40.1 µg g−1) and Eurasian watermilfoil (Myriophyllum spicatum L.) (A192 =25.3 µg g−1). Evidence of translocation was observed in all rooted species tested with the greatest translocation observed in N. cristata (1.28 µg g-1 at 192 HAT). The results of this study add to the growing body of knowledge surrounding the behavior of this newly registered herbicide within aquatic plants.
