EFFECTS OF VANTAGE(r) (SETHODYDIM) ON SEED HEAD DENSITY AND BIOMASS OF REED 
CANARYGRASS (PHALARIS ARUNDINACEA L.)

Craig A. Annen1, 2, Robin W. Tyser1, 3, and Eileen M. Kirsch3
1University of Wisconsin - La Crosse, La Crosse WI 54601 2U.S. Army Corps of 
Engineers, Mississippi River Project, La Crescent, MN  55947 3U.S. Geological 
Survey, Upper Midwest Environmental Sciences Center, La Crosse, WI  54602.

Reed canarygrass (Phalaris arundinacea L.) is an invasive cool season perennial 
grass that threatens the biodiversity of native vegetation in sedge meadows, wet 
meadows, and wet prairies.  This species is widely distributed along the 
floodplains of the Upper Mississippi River (UMR) and its major tributaries.  
Vantage(r), a grass-specific herbicide, may facilitate reestablishment of native 
vegetation with concomitant chemical control of reed canarygrass.  A study was 
conducted to test the efficacy of Vantage(r) for reducing seed head density and 
biomass of reed canarygrass.  Three treatments were tested in a randomized 
complete block design with eight replications:  (1) control (no herbicide 
application), (2) one herbicide application (early summer), and (3) two 
herbicide applications (early & late summer).  The application site was a wet 
meadow along the La Crosse River dominated by reed canarygrass.  Treatment with 
Vantage(r) reduced seed head density by 91 - 98% of the controls.  Aboveground 
biomass was reduced by 46 - 56%.  There were no biologically significant 
differences between the two treatment regimes for either of the responses 
measured.  We conclude that Vantage(r) herbicide controls reed canarygrass at 
economic rates without harming sedges and forbs, but that multiple-year 
applications may be necessary to completely eradicate the species.