Response of Asiatic Dayflower (Commelina communis) to Glyphosate and Alternatives in Soybean

Abstract

Asiatic dayflower has recently become a troublesome weed in eastern Iowa. This weed demonstrates an extended emergence period and there is anecdotal evidence of glyphosate tolerance. Thus, Asiatic dayflower is difficult to manage in glyphosate-resistant (GR) corn and soybean. Greenhouse experiments were conducted to evaluate the response of Asiatic dayflower to glyphosate applied at different rates and growth stages. Field research was conducted in 2005 and 2006 to evaluate different herbicides for Asiatic dayflower control in soybean. PRE herbicides were applied at planting and POST herbicides were applied 21 and 42 d after planting (DAP). In addition, shikimate accumulation in response to glyphosate was compared among Asiatic dayflower and GR and non-GR corn and soybean. Under greenhouse conditions, a single application of glyphosate (0.84 kg ae ha−1) did not control Asiatic dayflower. Only the highest rate evaluated, 13.44 kg ae ha−1 (16X), was lethal to Asiatic dayflower. Even when applied at an early growth stage (two leaves) and using high rates (3.36 kg ae ha−1), glyphosate controlled Asiatic dayflower just 28%. In the field, metribuzin and KIH-485 controlled Asiatic dayflower 80 and 73%, respectively. Early POST applications (21 DAP) of cloransulam or lactofen controlled Asiatic dayflower 80 and 67%, respectively. A single glyphosate application of 0.86 kg ae ha−1 controlled Asiatic dayflower approximately 50%. Glyphosate-treated Asiatic dayflower and non-GR corn and soybeans accumulated shikimate after application. GR corn and soybeans did not accumulate shikimate in response to glyphosate. Twenty-one days after treatment, all the non-GR soybean and corn plants died; however, Asiatic dayflower plants survived.

Studies on the inhibition of plant very-long-chain fatty acid elongase by a novel herbicide, pyroxasulfone

“…In this study, the reaction mixture contained 20 ml microsomal suspension, 5 ml of 20 mM NADH, 5 ml of 20 mM NADPH, 10 ml of 200 mM [2-14 C]-malonyl-CoA, 3 ml pyroxasulfone in acetone solution, 5 ml of 2 mM C24 : 0-CoA and H 2 O to 60 ml volume. The reaction mixture except for [2-14 C]-malonyl-CoA was pre-incubated for various time intervals at 30°C, and then the reaction was started by the addition of [2][3][4][5][6][7][8][9][10][11][12][13][14] C] malonyl-CoA. In the reaction without pre-incubation, microsomal suspension was added to the reaction mixture except for the microsomal fraction and then the reaction was started.…”

“…Pyroxasulfone (3-[5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl) pyrazol-4-ylmethylsulfonyl]-4,5-dihydro-5,5-dimethyl-1,2-oxazole; code name KIH-485) is a novel pre-emergence herbicide for use in wheat, 1) corn, [2][3][4][5][6] soybean 7) and other crops. 1,[8][9][10][11] This herbicide provides good efficacy on both grass and broadleaf weeds.…”

Role of metabolism in the selectivity of a herbicide, pyroxasulfone, between wheat and rigid ryegrass seedlings

“…P y roxasu lfone(3-[5-(dif luoromet hoxy)-1-met hy l-3-(trifluoromethyl) pyrazol-4-ylmethylsulfonyl]-4,5-dihydro-5,5-dimethyl-1,2-oxazole; code name KIH-485) is a novel preemergence herbicide for use in wheat, 1) corn, [2][3][4][5][6] soybean 7) and other crops. 1,[8][9][10][11] This herbicide is effective on both grass and broadleaf weeds.…”

Weed control in conventional soybean with pendimethalin followed by imazethapyr plus imazamox/quizalofop

“…In previous research, control of Benghal dayflower by glyphosate was only 53% at 21 d after treatment (Culpepper et al 2004) and <68% even at the highest glyphosate rate of 2.58 kg a.e. ha −1 (Ulloa and Owen 2009). Additionally, it has an aggressive growth habit, along with the ability to creep along the soil and root adventitiously at the nodes, increasing the potential for survival (Kuhns and Harpster 2004).…”