Abstract

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.

Keywords

Johnsongrass, chemical eradication, Outrider, noxious weeds, SPR-2398

Report Number

FHWA/IN/JTRP-2004/09

SPR Number

2398

Performing Organization

Joint Transportation Research Program

Publisher Place

West Lafayette, IN

Date of Version

2004

DOI

10.5703/1288284313277

Project Number

C-36-48P

File Number

9-5-15

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