Forb response to herbicides in a degraded tallgrass prairie

Herbicides are useful tools to manage undesirable plants on grasslands. However, the negative response of desirable plants is a common concern when herbicides are used to manipulate grassland plant composition. Our objective was to determine the response of the forb community in a tallgrass prairie following herbicide application to manage Rhus glabra L. (smooth sumac). Two experiments (replicated in space and time) were conducted to evaluate forb response to selected herbicides, application rates, and broadcast spray and hand-held wick application techniques. In Experiment 1, the shrub Amorpha canescens Pursh (leadplant) had the greatest frequency where 2,4-D was selectively applied with a wick and Ambrosia psilostachya DC. (western ragweed) and Solidago missouriensis Nutt. (Missouri goldenrod) were greatest where glyphosate was applied with a wick, whereas Aster ericoides L. (heath aster) frequency was greatest where no herbicide was applied. In Experiment 2, Helianthus annus L. (annual sunflower) frequency was greatest where piclorarn was broadcast applied. Species richness varied by treatment in Experiment 1 with the greatest species richness in the areas where picloram + 2,4-D and glyphosate were applied with a wick. In Experiment 2, species richness did not differ among treatments. We determined that wick-applied herbicides were less detrimental to the forb community than broadcast spraying when managing R. glabra in a tallgrass prairie.