Effect of Cumyluron or Bensulide On Root Growth of Creeping Bentgrass (Agrostis palustris Huds.) Grown in Aquaculture.

Cumyluron is a substituted urea herbicide under development by Helena Chemical Co. for selective postemergence removal of annual bluegrass (Poa annua L.) [ABG] in creeping bentgrass (Agrostis palustris H.) [CBG]. Greenhouse experiments were conducted in 2009 and 2010 to examine the effect of cumyluron herbicide on root growth of CBG grown in aquaculture. Individual tillers of each species were cultured in solution for 28 d. Nursery plugs were grouped by size and root length was trimmed to 13 cm immediately before herbicide exposure. Herbicides were added to the aquaculture solution at five levels; none, cumlyuron at 0.5, 1.0, or 2.0 g ai m^-1, and bensulide at 1.69 g ai m^-1. Root length [RL] and visual assessment of surface vegetation (density, vigor, growth rate, and injury) were assessed weekly. Root length of cumyluron treated plugs was unchanged through 49 DAT, whereas RL for bensulide and UTC increased to 23 and 30 cm, respectively. No differences between treatments were evident from surface vegetation evaluations for CBG.