Managing bluegrass

AGRONOMIC INFORMATION FROM ONTARIO'S CROP SPECIALISTS

Mike Cowbrough, Weed Specialist, Ontario Ministry of Agriculture, Food and Rural Affairs

BLUEGRASS COMPETITION IN winter wheat can result in up to 50 per cent yield losses. Over the past two seasons, three herbicides (Simplicity GoDri, Varro and Axial) have shown promising results and have prevented significant yield loss in winter wheat.

bluegrass
competitive
Francois Tardif
lodged
peter smith
steve lake
winter wheat
yield

THE DENSE STAND OF BLUEGRASS LODGED WINTER WHEAT (LEFT) COMPARED TO WHERE ADEQUATE CONTROL WAS ACHIEVED (RIGHT). IN 2022, BLUEGRASS COMPETITION REDUCED WINTER WHEAT YIELDS BY 50 PER CENT AND REDUCED HARVEST SPEED BY 30 PER CENT. PHOTO COURTESY OF MIKE COWBROUGH.

SIMPLICITY GODRI, VARRO, AND AXIAL PROVIDED GOOD CONTROL OF BLUEGRASS COMPARED TO THE UN-SPRAYED CHECK, WHERE BLUEGRASS HEADED ABOVE WINTER WHEAT. PHOTO COURTESY OF MIKE COWBROUGH.

These competitive grassy weeds emerge in the fall and early spring. Plants smaller than 10 centimetres in height are easier to control with herbicides, and early spring applications provide better control than fall applications. Some bluegrass seedlings — that are missed by fall applications — emerge in early spring. Both fall and early spring applications provide better control than late spring applications.

Acknowledgements: A huge thanks to Steve Lake, Peter Smith and François Tardif for supporting this research. •