Recommended CitationMorré, D. J. New Combination Treatments for Control of Johnsongrass Along Roadsides. Publication FHWA/IN/JTRP-2004/09. Joint Transportation Research Program, Indiana Department of Transportation and Purdue University, West Lafayette, Indiana, 2004. doi: 10.5703/1288284313277.
This project was to develop a cost-effective method for chemical eradication of Johnsongrass along Indiana roadsides. Johnsongrass, together with Canada thistle, represents Indiana’s most serious noxious weed invader where the need for control is mandated by law. Combined target-directed laboratory and greenhouse studies identified a new candidate herbicide, Outrider, which when combined with a new additive designated TR-IV gives eradication of Johnsongrass when applied to plants after less than 20 inches (70 cm) of growth or regrowth following mowing. The combination does not harm oversprayed established fescue or bluegrass. Based on limited implementation activities (two years experience), the recommendation is as a spot treatment. A cold-adapted Johnsongrass ecotype has been identified in the Northern-most tier of counties in Indiana which provides a further threat of encroachment of roadside-established Johnsongrass onto adjacent cropland of considerable potential economic consequence.
Johnsongrass, chemical eradication, Outrider, noxious weeds, SPR-2398
Joint Transportation Research Program
West Lafayette, IN
Date of this Version