By Tracy Turner
Now is the time for growers to check their wheat crops to see if last month’s cold snap injured susceptible plants, a field crops expert in the College of Food, Agricultural, and Environmental Sciences at The Ohio State University said.
Because temperatures hit near or below freezing during the week of April 20 in some parts of Ohio, wheat growers may consider checking their crops for potential injury, said Laura Lindsey, a soybean and small grains specialist with Ohio State University Extension. OSU Extension is the college’s outreach arm.
Depending on the wheat’s growth stage and how cold the temperatures were, some plants could have been hurt by the freeze, Lindsey said, noting that the later the growth stage of the plant, the more potential for damage.
“As wheat greens up, the plants are more susceptible to damage in freezing temperatures, especially after jointing,” she said. “Based on observations and reports we’ve received from some growers with concerns about the cold and its impact on their wheat crops, we think maybe 3 to 5 percent of fields may have sustained injury in Ohio.”
Statewide, most wheat is between Feekes growth stage 5, or green-up, and Feekes growth stage 6, or jointing, Lindsey said. For plants at Feekes growth stage 6, exposure to temperatures below 24 degrees for at least two hours can cause injury, she said.
“The damage to the plant is the most severe when the wheat is at the boot and heading growth stage,” Lindsey said. “Growers whose crops have experienced significant damage still have time to consider whether it would be more advantageous to get rid of the wheat crop and plant soybeans instead.”
Signs of wheat injury include discoloration and deformation, she said. For example, on plants in between Feekes growth stages 6 and 8, leaves and stems on freeze-damaged plants become twisted and turn light green or yellow with death of the leaf tips, Lindsey said.
“At Feekes 8, the emerging flag leaf appears yellow or dead instead of being a normal healthy green color,” she said. “Secondary unaffected tillers will still develop and produce grain, but those tillers with damaged growing points will stop growing and will not produce a head.”