The 2010-11 wheat crop is off to an excellent start. Most growers planted all their intended acres, and stands are very good, with few exceptions.
Early planted wheat (mid to late October) is growing rapidly and is beginning to tiller (Feekes 2). Italian ryegrass (Lolium multiflorum) infestations are heavy across the region, especially in early planted wheat, and is also beginning to tiller. We have observed numerous fields with ryegrass populations so thick they are choking out the wheat plants and preventing them from tillering.
The most effective herbicide available for ryegrass control in wheat is Axial XL. It has provided 95 to 99 percent control of this weed in our research trials. Hoelon is also labeled, but it has been slipping in recent years, and now only provides suppression of this pest. The sulfonylurea herbicides (Amber, Glean, Finesse, Osprey) are no longer effective on our ryegrass populations.
Axial XL is labeled to be applied from the 1-leaf stage of ryegrass to the emergence of the third tiller. It has already achieved this stage in the early planted wheat. Many producers prefer to wait until after the first of the year to apply their herbicide for ryegrass control. While Axial XL will usually still control larger ryegrass plants, it is more productive to apply it to ryegrass plants when they are smaller. Ryegrass is more competitive than wheat and if left unchecked heavy ryegrass infestations will reduce tillering in wheat, which can ultimately reduce yields.
Axial XL will only control grasses, but it can be tank mixed with a sulfonylurea herbicide for broadleaf weed control.
In addition to the sulfonylurea herbicides listed above, Ally (metsulfuron) or Peak can be used. Peak has the shortest residual of these sulfonylurea herbicides, and corn and grain sorghum can be planted behind it in the event of a wheat crop failure. Banvel and 2, 4-D are also options for broadleaf weed control, but they provide little or no residual and should not be applied in the fall.