| Abstract/Contents: | "Two studies were conducted at the Auburn University Turfgrass Research Unit, Auburn, AL to evaluate herbicide control of various legume species. Study one evaluated cool-season legume response to common turf herbicides. Legumes, including white clover (Trifolium repens), small hop clover (T. dubium), rabbitfoot clover (T. arvense), crimson clover (T. incarnatum), ball clover (T. nigrescens), and spotted burclover (Medicago arabica) were transplanted into dormant bermudagrass (Cynodon dactylon) turf February 10, 2010. The study was conducted as a randomized complete block design with six species as randomized sub-units within each main plot. Main plot treatments included a non-treated control and eleven herbicide treatments: 2,4-D amine (15.8 g ae 100 m-2), 2,4-DB amine (15.8 g ae 100 m-2), dicamba (11.2 g ae 100 m-2), MCPA (5.2 g ai 100 m-2), triclopyr (5.6 g ai 100 m-2), clopyralid (4.2 g ai 100 m-2), bentazon (11.2 g ai 100 m-2), metsulfuron methyl (0.21 g ai 100 m-2), trifloxysulfuron (0.28 g ai 100 m-2), imazaquin (5.6 g ai 100 m-2), and atrazine (22.4 g ai 100 m-2). Herbicides were applied March 10, and legume control was visually assessed relative to the non-treated check 2, 4, and 6 weeks after treatment (WAT). A legume-species by herbicide interaction was observed 4 and 6 WAT. In general, bentazon was least injurious to all clover species while dicamba, clopyralid, triclopyr, and atrazine effectively controlled all species. Ball, rabbitfoot, and white -clovers were partially tolerant to 2,4-DB (< 40% control). Other notable results include rabbitfoot clover tolerance to trifloxysulfuron and imazaquin as well as white clover tolerance to MCPA and imazaquin. These results indicate varying tolerances between legume species and common turf herbicides. Study two evaluated herbicide control of common lespedeza (Kummerowia striata) within maintained centipedegrass (Eremochloa ophiuroides) turf Treatments included a non-treated control and eleven herbicide treatments: 2,4-D amine (15.8 g ae 100 m-2), dicamba (11.2 g ae 100m-2), TrimecĀ® Southern (12.89 g ae 100 m-2; a combination product of MCPA, 2,4-D, and dicamba), Escaladeā¢ 2 (16.82 g ae 100 m-2; a combination product of 2,4-D, fluroxypyr, and dicamba), Celsiusā¢ (2.34 g ai 100 m-2; a combination product of dicamba, thiencarbazone, and iodosulfuron), carfentrazone (0.34 g ai 100 m-2), fluroxypyr (5.26 g ae 100 m-2), chlorsulfuron (0.53 g ai 100 m-2), two rates of aminocyclopyrachlor (0.79 and 1.05 g ai 100 m-2), and atrazine plus bentazon (22.42 and 8.41 g ai 100 m-2, respectively). Herbicides were applied August 4, 2010. Lespedeza control and centipedegrass injury were visually assessed relative to the non-treated check 2, 4, and 6 WAT. Dicamba, fluroxypyr, chlorsulfuron, both rates of aminocyclopyrachlor, atrazine plus bentazon, and Escalade 2 all controlled common lespedeza greater than 78% 6 WAT. Centipedegrass injury (>40%) did occur due to both rates of aminocyclopyrachlor application; however, injury subsided 6 WAT. It should be noted that both rates of aminocyclopyrachlor within this study were greater than current labeled rate for Imprelisā¢ herbicide (0.53 g ai 100 m-2). Carfentrazone, 2,4-D, Trimec Southern, and Celsius controlled common lespedeza less than 35% across all rating dates." |
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