Controlling lesser swinecress in creeping bentgrass greens

The prevalence of lesser swinecress (Coronopus didymus (L.) Sm.) on golf courses has increased over the last decade. Tolerance to close mowing, heavy traffic and the ability to reproduce under intense management conditions has led to infestations of lesser swinecress on creeping bentgrass putting greens.

Minimal research has examined the postemergence control of lesser swinecress in turf. Field experiments were initiated during 2009 and 2011 in Fort Stockton, Texas, on established lesser swinecress infestations present in an L-93 creeping bentgrass putting green. Treatments included three herbicides applied once and sequentially. Herbicide treatments were MCPP + 2,4-D + dicamba (0.238 + 0.148 + 0.060 lbs. ae per acre), sulfentrazone (0.125 lbs. ae per acre) and carfentrazone (0.015 lbs. ae per acre). Treatments were applied on June 12, 2009 and May 31, 2011. Sequential applications were made five weeks after initial treatment on July 17, 2009 and July 5, 2011. A non-treated check was included for comparison.

Creeping bentgrass phytotoxicity was ≤ 2 percent throughout the length of the trial, regardless of herbicide treatment. Plots treated with MCPP + 2,4-D + dicamba resulted in 86 percent lesser swinecress control four weeks after initial treatment. Plots treated with sulfentrazone had 22 percent lesser swinecress control, while carfentrazone was ineffective four weeks after initial treatment. Single and sequential applications of MCPP + 2,4-D + dicamba resulted in 91 percent and 99 percent lesser swinecress control, respectively, 10 weeks after initial treatment. Control with single and sequential applications of sulfentrazone was 14 percent and 31 percent respectively, 10 weeks after initial treatment. No lesser swinecress control was observed 10 weeks after initial treatment in response to single and sequential applications of carfentrazone.

Sequential applications of MCPP + 2,4-D + dicamba controlled lesser swinecress in this study without injuring creeping bentgrass turf. Thus, this herbicide may provide superintendents with a new option for lesser swinecress control in creeping bentgrass putting greens.

Jared Hoyle, Ph.D., Chase Straw, Gerald Henry, Ph.D., Tyler Cooper, Leslie Beck, Ph.D., and AJ Hephner.