North Carolina’s Central Piedmont region was hit with temperatures of 20 degrees on March 29 which dealt a blow to the area’s wheat crop, according to Paul Murphy, small grains breeder at North Carolina State University.
“You guys in this area were terribly unfortunate. The rest of the state didn’t experience the temperatures you did, but from Salisbury up to Statesville, you got down to 20 degrees. Greensboro didn’t get hit and Boone didn’t get hit, but unfortunately you guys did, which really dealt a blow to your early maturing wheat varieties,” Murphy said at a small grains field day at the Piedmont Research Station in Salisbury, N.C. April 16.
Murphy said it is still too early to tell what the yield loss will be but he pointed out that if the wheat crop loses 50 percent of its primary tillers due to freeze damage, the final yield will be 25 percent less as the secondary tillers compensate for the loss from the primary tillers.
“The primary tillers are the ones that are growing the fastest. They’re dead and lodged. The secondary tillers are now growing to try to compensate for the loss of the primary tillers,” Murphy said, as he showed the freeze damage to a test plot with early maturity wheat varieties.
Murphy said wheat in North Carolina transitions from vegetative growth to reproductive growth during the first two weeks of March. It is when the plant moves to the reproductive stage that it is most susceptible to freeze damage, he explained.
“The growing point of the plant begins to emerge from under the soil and the growing point is usually just above the highest node. To see if you have transitioned to reproductive growth, just feel the bottom of the stem and when you can feel the bump or the node, you know that you have transitioned to the reproductive phase and the growing head is just above the topmost node,” he said.
Murphy pointed out that wheat is most susceptible to freeze damage at this stage, when even temperatures at 30 degrees for two hours can devastate a wheat crop. “Early reproductive growth freeze damage is relatively unusual in North Carolina, but it did hit the Piedmont this year,” he said.
The rest of the state’s wheat crop is looking good and didn’t suffer springtime freeze damage, although the crop is a week to 10 days behind due to cold weather, Murphy said.
In the meantime, N.C. State University researchers are seeking new methods to control Italian ryegrass in wheat as the weed continues to build resistance to most of the herbicides available in North Carolina, according to Wes Everman, Extension weed specialist at N.C. State.
“We really don’t have new options on the horizon. We have one or two experimental compounds we’re starting to look at but they still have to get through all the regulatory hurdles,” Everman said. “The challenge is the regulatory environment. It’s going to be harder and harder to have new chemicals so some of the work we are doing is to look at some of the cultural practices we can use to handle ryegrass.”
In a study this year, N.C. State researchers are comparing no-till to turbo-till and are examining row spacing instead of broadcasting at planting as a means to control Italian ryegrass, Everman said.
Zach Taylor, an N.C. State graduate student, is conducting the study at the Piedmont Research Station and explained that the same herbicide treatment is used in both the no-till plot and the turbo- till plot. Pre-emergence, post emergence and residual treatments were used in both plots, he explained.
“In this location we see an initial emergence of ryegrass in the fall. In the spring, we see a second flush of ryegrass come up and germinate so we included a residual treatment with our post to take care what’s coming up in the spring and we kill those weeds that are already up,” Taylor said. “Our best program is when we start with a pre, followed by a post with a residual. The best way to go is to really tackle that ryegrass and control it.”