Tuesday, November 14, 2006

Identification of Prodiamine-Resistant Annual Bluegrass in Tennessee.

Matthew Cutulle1, J. Scott McElroy2, and Neal Stewart1. (1) Plant Sci Dept, Univ. of Tenn, 2431 Joe Johnson Dr,252 Plnt Sci Bd, Knoxville, TN 37996, (2) 2431 Joe Johnson Dr, University of Tennessee-Knoxville, University of Tennessee, Plant Sciences Dept./ 252 Plant Sciences Bldg, Knoxville, TN 37996-4561

Dinitroaniline herbicide resistant annual bluegrass (Poa annua L.) has been reported in North Carolina due to the repeated use of prodiamine in golf course fairways.  However, in Tennessee there have been no reported cases of annual bluegrass resistance to any dinitroaniline herbicides.  Reduced preemergence control of annual bluegrass with prodiamine was reported at Eagle Bluff Golf Course in Chattanooga, Tenn.  Seeds were harvested from Eagle Bluff and evaluated for prodiamine resistance.  A sterile gel-media with increasing concentrations of prodiamine was used to grow and screen annual bluegrass seeds for resistance.  An increase in tolerance of the Chattanooga population when compared to a known susceptible population was observed. The gel-media screen is an effective diagnostic tool for monitoring prodiamine resistance due to its rapidity and minimization of confounding variables.  Future research will focus on the use of a gel-media screen compared to standard dinitroaniline resistance screen techniques, such as greenhouse soil-media evaluations and filter paper/petri-dish methodology.  Additional research will also evaluate the resistance of the Eagle Bluff population to resistance to pendimethalin and dithiopyr.