Comparison of Torpedograss and Pickerelweed Susceptibility to Glyphosate

Gettys, Lyn A. and Sutton, David L. (2004) Comparison of Torpedograss and Pickerelweed Susceptibility to Glyphosate. Journal of Aquatic Plant Management, 42, pp. 95-99.

Preview

PDF - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader Download (65Kb) | Preview

Abstract

Torpedograss (Panicum repens L.) is one of the most invasive exotic plants in aquatic systems. Repeat applications of (N-phosphonomethyl) glycine (glyphosate) herbicides provide limited control of torpedograss; unfortunately, glyphosate often negatively impacts most non-target native species that grow alongside the weed. This experiment studied the effect of glyphosate on pickerelweed (Pontederia cordata L.), a native plant that shares habitats with torpedograss. Actively growing plants of torpedograss and pickerelweed were cultured in 8-liter containers and sprayed to wet with one of four rates of glyphosate: 0%, 0.75%, 1.0%, or 1.5%. Each treatment included a surfactant to aid in herbicide uptake and a surface dye to verify uniform application of the treatments. All herbicide treatments were applied with a backpack sprayer to intact plants and to cut stubble of both species. Four replicates were treated for each species-rategrowth combination during each of two experiment periods. Plant dry weights 8 weeks after herbicide application suggest that torpedograss was effectively controlled by the highest rate of glyphosate applied to cut stubble. Pickerelweed was unaffected when the highest rate of glyphosate was applied as a cut-and-spray treatment. These data suggest that a cut-and-spray application of a 1.5% solution of glyphosate may be an effective strategy to control torpedograss without deleteriously affecting pickerelweed. (PDF contains 4 pages.)

Actions (login required)