Enhancing Extension Education Recommendations to Minimize Spread of Invasive Species and Establish New Grasses for Georgia Roadsides

Current Georgia Department of Transportation (DOT) management practices could be contributing to the release of invasive weeds, such as broomsedge and vaseygrass, on Georgia roadsides. The herbicide imazapic, used to reduce mowing requirements of roadside grasses, injured bermudagrass twice as much as broomsedge, an invasive species, in greenhouse experiments. Imazapic provided no control of broomsedge in the field. MSMA applied in fall provided good control of broomsedge for 1 year after initial treatment. However, imazapic tank-mixed with MSMA provided less control than MSMA alone, suggesting imazapic antagonizes efficacy of MSMA on broomsedge. The new herbicides Derigo and Pastora controlled or suppressed vaseygrass populations when applied in late spring. However, these herbicides did not control broomsedge. MSMA will need to be applied in sequential programs when ALS inhibitors are used for controlling other weeds or for growth regulation of roadside grasses. Introducing new grasses for roadside vegetation could reduce the spread of invasive weeds and enhance management. Centipedegrass and zoysiagrass have potential to establish under roadside conditions as alternatives to bermudagrass and fescue in Georgia. These grasses effectively established when planted from sod or plugs. Centipedegrass was the quickest grass to establish from sod. Growth of centipedegrass was comparable to zoysiagrass from plugs, and both species were more competitive than bermudagrass under guardrails. None of the grasses established from seed under simulated roadside conditions. Significant differences in vaseygrass germination were detected by location. Vaseygrass seed germinated in June from collections in south Georgia. Seed germination was detected from July to November in Newnan, but other locations had minimal germination in fall. These results suggest that mowing operations could spread significant amounts of viable seed throughout the state from June to November.


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Figures; Photos; Tables;
  • Pagination: 43p

Subject/Index Terms

Filing Info

  • Accession Number: 01599252
  • Record Type: Publication
  • Report/Paper Numbers: FHWA-GA-16-1237, GDOT Research Project 12-37
  • Contract Numbers: 0011852
  • Created Date: May 2 2016 1:32PM