The head capsule is tarnish-brown and the rear end terminates in a short, blunt point. The larva feeds within the wheat stem, boring down through the joints, and by late summer has reached the lower parts of the plant close to the surface of the ground. Here it cuts a V-shaped groove entirely around and inside the stem, which causes the stem to break off. Sawfly damage occurs annually in North Dakota. This insect primarily affects wheat in the central and western areas of the state.
Additional loss occurs when infested stems lodge, rendering the grain unharvestable.
Larvae overwinter in the wheat stubble making infested sites the source of next year's problems. This strategy requires field surveys to determine infestation levels. Infested stems have a reddish-brown spot below the 2nd or 3rd node. Determine the percent of stems infested at each site. Fall tillage . . .