Maintaining the quality and adequate flow of waterways is a high priority among landowners, communities, and others responsible for the management of water resources. Hydrilla (Hydrilla verticillata) is an especially troublesome aquatic weed that degrades water quality, displaces native aquatic plants, and reduces oxygen levels. Thick mats of hydrilla can reduce water flow rates by 90 percent, seriously impeding the productive use of canals, irrigation systems, and other waterways. Many water resources are diminished because hydrilla infestations cannot be remedied, despite millions of dollars spent annually on its management. Aquatic-weed management has long been the focus at the U.S. Army Engineer Research and Development Center-Environmental Laboratory (ERDC-EL). ERDC-EL is the primary research entity for developing and evaluating new chemical and biological control techniques for aquatic systems in the United States. Because natural water bodies are sensitive ecological systems, any management technique used to reduce nuisance vegetation must be species-selective, while also minimizing any adverse impact to the aquatic environment and its users. With the discovery that the biological fungal pathogen Mycoleptodiscus terrestris is effective against hydrilla, Dr. Judy Shearer recognized an opportunity to develop an alternative to the chemical herbicides typically employed in hydrilla management. In 2000, ERDC-EL and commercial partner SePRO Corporation of Carmel, Ind., executed a Cooperative Research and Development Agreement (CRADA) for development of the M. terrestris pathogen into a biologically based mycoherbicide for hydrilla management. Shortly thereafter, the U.S. Department of Agriculture’s National Center for Agricultural Utilization Research (USDANCAUR) also entered into a CRADA with SePRO with the same objective in mind. The combined effort resulted in a patent that covers not only the fungus studied, but any fungus that produces microsclerotia in broth culture and can be used for aquatic plant control. In 2005, this patent was licensed to SePRO Corporation, which then entered into additional CRADAs with each laboratory to support the continued research and development of M. terrestris into a commercial bioherbicide. Each new formulation of the mycoherbicide is evaluated at ERDC-EL for its effectiveness controlling hydrilla. The goal of this publicprivate research effort is the development of a commercial formulation capable of controlling hydrilla in larger bodies of water. Large-scale testing in 2009 brought the product closer to the Environmental Protection Agency’s (EPA) required registration and widespread use in U.S. waterways.