Multi-state survey to identify suspected resistance to four herbicides and one plant growth regulator in Poa annua

Authors: BOWLING, REBECCA - University Of Tennessee; MCCURDY, JAMES - Mississippi State University; DE CASTRO, EDICARLOS - Bracell Limited; PATTON, AARON - Purdue University; ASKEW, SHAWN - Virginia Tech; BROSNAN, JAMES - University Of Tennessee; BREEDEN, GREGORY - University Of Tennessee; ELMORE, MATTHEW - Rutgers University; GANNON, TRAVIS - University Of North Carolina; GONCALVES, CLEBSON - University Of California; KAMINSKI, JOHN - Pennsylvania State University; KOWALEWSKI, ALEC - Oregon State University; Mattox, Clint; MCCARTY, LAMBERT - Clemson University; MCCULLOUGH, PATRICK - University Of Georgia; MCELROY, SCOTT - Auburn University; MCKEITHEN, CHASE - University Of Florida; OSBURN, ANDREW - Texas A&M University; ROGERS, RONALD - North Carolina State University; RUTLAND, CLAUDIA ANN - Auburn University; TAYLOR, JACOB - Clemson University; UNRUH, BRYAN - University Of Florida; VARGAS, JOSE - University Of Tennessee; BAGAYATHIANNAN, MUTHUKUMAR - Texas A&M University

Submitted to: Crop, Forage & Turfgrass Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/5/2024
Publication Date: 8/17/2024
Citation: Bowling, R.G., Mccurdy, J.D., De Castro, E.B., Patton, A.J., Askew, S.D., Brosnan, J.T., Breeden, G.K., Elmore, M.T., Gannon, T.W., Goncalves, C., Kaminski, J.E., Kowalewski, A.R., Mattox, C.M., Mccarty, L.B., Mccullough, P.E., Mcelroy, S.J., Mckeithen, C., Osburn, A., Rogers, R.R., Rutland, C., Taylor, J., Unruh, B.J., Vargas, J.J., Bagayathiannan, M.V. 2024. Multi-state survey to identify suspected resistance to four herbicides and one plant growth regulator in Poa annua. Crop, Forage & Turfgrass Management. https://doi.org/10.1002/cft2.20300.
DOI: https://doi.org/10.1002/cft2.20300

Interpretive Summary: A multi-state project collected 866 annual bluegrass populations from the following turfgrass locations: sports fields, sod farms, commercial and residential lawns, and golf courses. Four different herbicides and a plant growth regulator were applied to a sub-set of these populations to assess herbicide resistance. In total, 16.8% of the populations tested were suspected to be resistant to at least one mode of action, whereas multiple resistance was suspected in 11.2% of those tested. Findings from this survey conclude that annual bluegrass herbicide resistance remains a challenge for the turfgrass sector, and these data also suggest that resistance is likely more dominant in the southern compared to the northern climactic zones.

Technical Abstract: A multi-state survey of annual bluegrass populations was conducted on sports fields, sod production facilities, commercial and residential lawns, as well as golf courses. These populations were treated with four herbicides and one plant growth regulator to assess their sensitivity to these applications. A total of 866 populations were collected, and the following number of populations were screened post-emergence at the 1X field recommended rate: 547 to diquat, 683 to ethofumesate, 724 to glufosinate, and 655 to mesotrione, as well as 713 to the plant growth regulator paclobutrazol. Suspected resistant populations of annual bluegrass were present in all turfgrass systems for all five products tested, except for diquat in commercial and residential lawns and sod production facilities. In total, 16.8% of the populations tested were suspected to be resistant to at least one mode of action, whereas multiple resistance was suspected in 11.2% of those tested. Findings from this survey conclude that annual bluegrass herbicide resistance remains a challenge for the turfgrass sector, and these data also suggest that resistance is likely more dominant in the southern compared to the northern climactic zones.