Evaluating the efficacy of granular copper and triclopyr alone and in combination for control of flowering rush Butomus umbellatus

Authors: TUMAGE, GRAY - Mississippi State University; WERSAL, RYAN - Lonza Corporation; Madsen, John

Submitted to: Journal of Aquatic Plant Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/2/2017
Publication Date: 7/1/2017
Citation: Tumage, G., Wersal, R.M., Madsen, J.D. 2017. Evaluating the efficacy of granular copper and triclopyr alone and in combination for control of flowering rush Butomus umbellatus. Journal of Aquatic Plant Management. 55:120-122.

Interpretive Summary: Flowering rush (Butomus umbellatus) is spreading across the United States as an invasive aquatic plant, yet an accepted recommendation for control of this noxious weed has not yet been determined. We tested two different copper complexes, granular triclopyr, and a protein solution alone and in combination to determine if these herbicides or combinations would be effective in controlling flowering rush. Triclopyr alone and with the copper complexes was effective in reducing above-and belowground biomass compared to an untreated reference. Further work should be pursued to examine control using triclopyr.

Technical Abstract: Flowering rush (Butomus umbellatus) is an invasive aquatic plant to lakes, reservoirs, rivers, and irrigation canals from New England to Washington State. At this point, there are no standard herbicide use patterns for control of this nuisance species. In this study, we evaluated the use of granular copper ethylenediamine and granular triclopyr formulations, alone and in combination to control flowering rush. Plants were grown for seven months in flats placed within thirty-six 1140 L mesocosm tanks. Water was added to the tanks to a depth of 41cm, or a volume of 757L. Prior to herbicide treatment, samples were collected for pretreatment biomass levels. Treatments included a granular copper-ethylenediamine (0.75 mg/L), liquid copper-ethanolamine complex (0.5 mg/L), granular triclopyr (1.5 mg/L), granular copper + granular triclopyr (0.5 + 1.5 mg/L), liquid copper complex and granular triclopyr (0.5 + 1.5 mg/L), and all of the above with a protein solution (0.001 ml/L). The experiment was replicated four times in tanks. Six weeks after treatment (WAT), all treatments and the untreated reference were harvested, separated to above- and belowground biomass, and dried at 70C for five days. Granular triclopyr alone, protein solution and granular triclopyr, and the triclopyr + protein solution + complexed copper combinations reduced aboveground and belowground biomass by six WAT.