Goosegrass (Eleusine indica L. Gaertn.) is a problematic C4 weedy grass species throughout the warmer regions of the world (Lee and Ngim, 2000; McCullough et al., 2016; Mudge et al., 1984). Nishimoto and McCarty (1997) noted optimal (99%) germination with fluctuating temperatures; 20 °C for 16 h and 35 °C for 8 h with supplemental light. Kerr et al. (2018) noted goosegrass life cycle was complete 68 d after emergence in late-summer/early autumn in Clemson, SC. Typically, goosegrass plants are killed with the first frost; however, in the tropical regions of the world, plants continue to tiller year round and behave more like a perennial. Also, seeds germinate year round, resulting in varying aged goosegrass plants, and inconsistent PRE and POST control efficacy.
Goosegrass control efficacy is effected, among other variables by the maturity of the plant. Previous research noted a reduction in control at the one- to two-tiller and four- to six-tiller growth stage, compared with the two- to four-leaf growth stage (Burke et al., 2005). McCarty (1991) noted differences in goosegrass control with diclofop based on goosegrass mowing height. Greatest control was achieved on goosegrass maintained at 1.3 cm, compared with higher heights or unmown. The addition of metribuzin with diclofop improved control efficacy of mature goosegrass plants.
End-user options for goosegrass control efficacy while maintaining acceptable turfgrass quality has decreased over the past decade or so, due to reduced performance for certain herbicides (e.g., foramsulfuron), specific goosegrass herbicides (e.g., diclofop-methyl) being removed from the market, and the removal and/or severe use reductions of other herbicides (e.g., monosodium methanearsonate). Current goosegrass control options (e.g., topramezone, metribuzin) also have activity on warm-season turfgrass, often resulting in unacceptable injury. Developing management techniques to improve the selectivity of POST herbicides provides end-users more options for effective goosegrass control. Possible means of obtaining control, yet maintaining turf quality is immediately incorporating applied products via irrigation. Because metribuzin and topramezone have some or all root absorption, this strategy is hypothesized to provide desired goosegrass control, yet minimizing undesirable turfgrass injury (Abusteit et al., 1985; Elmore et al., 2011). The objectives of the trials were 1) evaluate turfgrass injury following use of POST goosegrass control options; 2) assess if irrigating immediately following the herbicide application reduces injury of ‘Tifway 419’ bermudagrass [Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Burtt-Davy]; and 3) evaluate if immediate irrigation influences goosegrass control at one- to three-tiller and mature growth stage.
Abusteit, E.O., Corbin, F.T., Schmitt, D.P., Burton, J.W., Worsham, A.D. & Thompson, L. 1985 Absorption, translocation, and metabolism of metribuzin in diploid and tetraploid soybean (Glycine max) plants and cell cultures Weed Sci. 33 618 628
Armel, G.R., Rardon, P.L., McComrick, M.C. & Ferry, N.M. 2007 Differential response of several carotenoid biosynthesis inhibitors in mixtures with atrazine Weed Technol. 21 947 953
Burke, I.C., Askew, S.D., Corbett, J.L. & Wilcut, J.W. 2005 Glufosinate antagonizes clethodim control of goosegrass (Eleusine indica) Weed Technol. 19 664 668
Breeden, S.M., Brosnan, J.T., Breeden, G.K., Vargas, J.J., Eichberger, G., Tresch, S. & Laforest, M. 2017 Controlling dinitroaniline-resistant goosegrass (Eleusine indica) in turfgrass Weed Technol. 31 883 889
Cox, M.C., Rana, S.S., Brewer, J.R. & Askew, S.D. 2017 Goosegrass and bermudagrass response to rates and tank mixtures of topramezone and triclopyr Crop Sci. 57 1 12
Elmore, M.T., Brosnan, J.T., Kopsell, D.A. & Breeden, G.K. 2011 Methods of assessing bermudagrass (Cynodon dactylon) responses to HPPD-inhibiting herbicides Crop Sci. 51 2840 2845
Kerr, R.A., McCarty, L.B., Bridges, W.C. & Cutulle, M. 2018 Key morphological events following late-season goosegrass (Eleusine indica) germination Weed Technol. 33 196 201
Lee, L.J. & Ngim, J. 2000 A first report of glyphosate-resistant goosegrass [Eleusine indica (L.) Gaertn] in Malaysia Pest Manag. Sci. 56 336 339
McCullough, P.E., Yu, J., Raymer, P.L. & Chen, Z. 2016 First report of ACCase-resistant goosegrass (Eleusine indica) in the United States Weed Sci. 64 399 408
Mudge, L.C., Gossett, B.J. & Murphy, T.R. 1984 Resistance of goosegrass (Eleusine indica) to dinitroaniline herbicides Weed Sci. 32 591 594
Nishimoto, R.K. & McCarty, L.B. 1997 Fluctuating temperature and light influence seed germination of goosegrass (Eleusine indica) Weed Sci. 1997 426 429
Nishimoto, R.K. & Murdoch, C.L. 1999 Mature goosegrass (Eleusine indica) control in bermudagrass (Cynodon dactylon) turf with a metribuzin–diclofop combination Weed Technol. 13 169 171