Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2015
Publication Date: 1/20/2015
Publication URL: https://handle.nal.usda.gov/10113/62376
Citation: Marble, S.C., Prior, S.A., Runion, G.B., Torbert III, H.A. 2015. Control of yellow and purple nutsedge in elevated co2 environments with glyphosate and halosulfuron. Frontiers in Plant Science. 6:1. doi 10.3389/fpls.2015.00001.
Interpretive Summary: The atmospheric concentration of CO2 is increasing. High CO2 can increase growth in not only crop species but also in weeds. This has raised questions on if weed management will be more problematic in a future CO2 enriched world. We tested the effectiveness of two herbicides (glyphosate and halosulfuron) on purple and yellow nutsedge at elevated and ambient CO2 levels to determine if herbicide efficacy would be reduced under high CO2. Both herbicides provided complete control of both nutsedges when used alone or in a tank-mix at rates ranging from 0.5 to 1.5 × the labeled rate. Both nutsedges grew larger under high CO2, but increased biomass did not correlate with increased herbicide tolerance. Based on our results, glyphosate and halosulfuron will provide effective control of both nutsedges in a future CO2 enriched world when applied at similar growth stages (10 and 20 cm in height for purple and yellow nutsedge, respectively). In order to prepare producers for weed control challenges in future environments, further research is needed to determine the impact elevated CO2 levels on additional weed species and herbicide active ingredients.
Technical Abstract: Atmospheric concentrations of carbon dioxide (CO2) have significantly increased over the past century and are expected to continue increasing in the future. While elevated levels of CO2 will likely result in higher crop yields, weed growth is also highly likely to increase. An experiment was conducted in 2012 to determine the effects of an elevated CO2 environment on glyphosate and halosulfuron efficacy for control of purple and yellow nutsedge (Cyperus rotundus L. and C. esculentus L.). Both species of nutsedge where grown in 3.0 L containers under either ambient or elevated (380 and 720 ppm CO2, respectively) CO2 in open-top field chambers and treated with 0.5×, 1.0×, and 1.5× of the manufacturer’s labeled rate of halosulfuron, glyphosate, or a tank mix of the two herbicides. Results show that both species of nutsedge had a positive growth response to elevated CO2, as purple nutsedge had increased shoot and root dry weights and yellow nutsedge had increased shoot, root, and tuber dry weights and counts. Few treatment differences were observed among the herbicides at any of the rates tested. By 3 wks after treatment, both purple and yellow nutsedge were adequately controlled by all herbicides and combinations at all rates tested, regardless of CO2 concentration. Based on this study, halosulfuron and glyphosate efficacy will not be affected by predicted future increased CO2 levels when applied at rates as low as 0.5× to either purple or yellow nutsedge at the growth stages described here.