||Herbicidal methodology for eradication of Kentucky tall fescue grass (Festuca arundinacea) and establishment of native warm-season grasses (NWSG) is relatively well developed. However, these technologies typically focused on use of glyphosate, imazapic, imazapyr, or combinations thereof. Some relatively new herbicide formulations that might have application for NWSG establishment have become available. The efficacy of these new products and formulations in fescue eradication and NWSG establishment has not been thoroughly
evaluated throughout the range of extant conditions. We tested efficacy of several herbicide treatments for eradicating fescue and controlling bermudagrass (Cynodon dactylon) on a prairie site in northeast Mississippi. Prior to any treatments, fescue canopy cover was approximately 97%. Prior to herbicidal applications, the field was prescribe-burned in late April 2004 to improve herbicide efficacy and to facilitate use of a native warm-season grass drill. Vegetation
was allowed to recover for three weeks following the burn. During this time, a substantial latent bermudagrass component was released in response to reduction in fescue competition associated
with the prescribed fire. Herbicide test plots were established in a randomized complete block design. Hillslope positions (n = 6) were treated as a blocking factor with seven 10- x 20-m plots/position. We randomly assigned each treatment to plots within each hillslope position. Blocks (hillslope position) and plots (herbicide treatment plots) were separated by a 5-m buffer strip. During mid-May 2004, we applied varying combinations of the following herbicide
treatments: (1) sulfosulfuron; (2) imazapic; (3) imazapyr; and (4) glyphosate. Vegetation structure was evaluated post-treatment in July 2004. We measured total canopy, bermudagrass canopy, fescue grass canopy, forb canopy, legume canopy, annual weed canopy, native warm season grass canopy cover, bare ground, litter cover, and litter depth. We used mixed model analysis of variance (ANOVA) in a randomized complete block design to evaluate vegetation
response to treatments. We blocked on hillslope positions (random effect) and considered treatments as fixed effects. By coincidence, we apparently eliminated most fescue grass with the timing of our prescribed burn. Imazapyr acid applied at 0.500 pounds/acre and imazapic acid applied at 0.188 pounds/acre + glyphosate salt at 2.000 pounds/acre herbicide treatments resulted in the most long-term, overall control of forage grasses and other vegetation. In the context of our study site and herbicide treatments, we suggest the imazapyr and imazapic + glyphosate treatments are most effective in controlling bermudagrass and other competing vegetation prior
to NWSG establishment. Given successful restoration of this research site to native grass/forb communities, this site should serve as a valuable public demonstration area for resource managers and private landowners.