Invasive Species Compendium

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Abstract

Carfentrazone improves broadleaf weed control in proso and foxtail millets.

Abstract

Proso (Panicum miliaceum) and foxtail millets (Setaria italica) are regionally important dryland crops for the semiarid portions of the Central Great Plains. However, few herbicides are registered for use in either crop. The efficacy of carfentrazone was studied in proso millet from 2003 through 2005 at the University of Nebraska High Plains Agricultural Laboratory located near Sidney, Nebraska, USA, and in foxtail millet in 2004 and 2005 at the University of Wyoming Sustainable Agriculture Research and Extension Center near Lingle, Wyoming. Carfentrazone was applied postemergence at 9.0, 13.5, and 18.0 g a.i./ha with combinations of 2,4-D amine, prosulfuron, and dicamba. Although leaves of treated plants exhibited localized necrosis, leaves emerging after treatment were healthy. Grain and forage yields were not affected by the application of carfentrazone. Dicamba and 2,4-D amine provided visual control of 30% or less for buffalobur (Solanum rostratum). Adding carfentrazone to one or both of these herbicides improved buffalobur control to 85% or greater. Carfentrazone applied at 18.0 g/ha improved Russian thistle (Salsola iberica), kochia (Kochia scoparia [Bassia scoparia]), and volunteer sunflower (Helianthus annuus) control in 2003, when plants were drought-stressed, but did not help with these and other weeds during wetter years. Carfentrazone provides proso millet producers with a way to selectively control buffalobur, a noxious weed in several western states. In foxtail millet, carfentrazone provides POST broadleaf weed control with little risk for serious crop injury. Crop injury has been a concern with 2,4-D, which is currently the only other herbicide registered for use in foxtail millet.