Sericea lespedeza control with postemergence and preemergence herbicide applications in fields managed for northern bobwhite

• Published in: Wildlife Society bulletin (2011) 2023-06, Vol.47 (2), p.n/a
• Main Authors: Turner, Mark A., Powell, Bonner L., Wade GeFellers, J., Bones, Jacob T., Marshall, Spencer G., Harper, Craig A.
• Format: Article
• Language: English
• Subjects: Colinus virginianus; early succession; imazapic; invasive species; Lespedeza cuneata; northern bobwhite; postemergence herbicide; preemergence herbicide
• ISSN: 2328-5540; 2328-5540
• DOI: 10.1002/wsb.1442

Sericea lespedeza (Lespedeza cuneata) is an invasive nonnative legume that commonly occurs on sites managed for northern bobwhite (Colinus virginianus). Sericea reduces bobwhite habitat availability by outcompeting native plants that provide food and cover. Sericea can be controlled with postemergence herbicides such as glyphosate as well as a mixture of triclopyr with fluroxypyr, but these herbicides do not provide preemergence control. Imazapic has been effective at controlling a limited number of planted sericea seeds, but the efficacy of imazapic at various application rates to control sericea seedbank response following treatment with a postemergence herbicide has not been evaluated. We designed a field experiment to evaluate sericea control and changes in the plant community as related to bobwhite habitat with 2 postemergence herbicides followed by preemergence treatment of imazapic at 3 sites in Tennessee and Alabama, USA, 2018–2022. Specifically, we treated sericea with postemergence broadcast applications of glyphosate or triclopyr with fluroxypyr in 2018 and applied spot treatment with the same herbicides in 2019–2021. We applied imazapic at 4 rates following prescribed fire in 2019 and 2022. We measured coverage of sericea, native forbs, annual grasses, perennial grasses, and bobwhite food plants before treatment in 2018 and after all treatments in 2022. Nearly all postemergence treatments reduced sericea coverage, but imazapic did not increase control compared to postemergence herbicides alone. Perennial grasses used for nesting and bobwhite foraging were maintained following treatments. We recommend managers use either glyphosate or triclopyr with fluroxypyr to control sericea postemergence and consider using a low rate of imazapic to reduce annual grasses if coverage is a problem on the site. We evaluated the use of glyphosate and triclopyr + fluroxypyr postemergence along with four different rates of preemergence imazapic to control sericea lespedeza. Postemergence treatments reduced sericea coverage while maintaining perennial grasses and bobwhite food plants. Although imazapic failed to improve sericea control, it may be useful for control of annual grasses on sites where annual grasses reduce openness at ground level.