VICKSBURG, Miss.— Studies conducted by research biologists at the U.S. Army Engineer Research and Development Center’s (ERDC) Environmental Laboratory (EL) on the management of the invasive aquatic plant flowering rush (Butomus umbellatus L.) were published in the 2021 Issue 59 of the peer-reviewed Journal of Aquatic Plant Management.
Dr. Bradley Sartain and Dr. Kurt Getsinger from ERDC-EL are credited as the first and second authors of the report. They are joined by 2020 ERDC University (ERDC-U) selectee Damian Walters, a wildlife biologist from the U.S. Army Corps of Engineers (USACE) Walla Walla District and third author.
Walters began his work with the team through ERDC-U, an initiative that pairs USACE division and district representatives with relevant laboratory mentors for a six-month research project. During that time, Walters experimented on the growth, sediment preference and feeding pressure responses of flowering rush. His goals focused on incorporating chemical, physical, biological and integrated control strategies to successfully manage and prevent the spread of flowering rush in run-of-the-river reservoir systems.
The research project focused on the “Evaluation of diquat, endothall, and diquat plus endothall under short exposure times for the management of Flowering Rush.”
“The adaptive plasticity of flowering rush to grow in a variety of habitat conditions has led to its spread and establishment in water bodies where a high rate of water-exchange can occur over a relatively short period of time,” Sartain said.
These conditions present a unique challenge for managing the species, and small-scale research evaluating contact herbicides under short — less than six hours — concentration exposure times (CETs) was lacking. This led the team to study ways to help manage flowering rush invasions which adversely affect native plants and wildlife habitats.
“Due to no significant exposure time effect at any of the harvest periods, it can be concluded that all exposures resulted in equal control of flowering rush shoot and rhizome biomass under controlled experimental conditions,” Sartain said. “In addition, no significant herbicide effect was detected for rhizome biomass at any of the three harvest periods.”
“However, the significant herbicide effect for control of flowering rush shoots 12 weeks after treatment indicates that diquat or products containing diquat are the best option for optimal reductions of flowering shoot biomass,” he continued. “Nonetheless, this research indicates that the contact herbicides evaluated, if applied in areas where CETs are greater than or equal to three hours, can be effective tools for managing vegetative and reproductive structures of flowering rush.”
For additional information on flower rush research, contact Bradley.T.Sartain@usace.army.mil.