from the University of Missouri Extension
The cold weather and snow of May 3 and May 4 could create problems in area wheat fields and corn fields according to Jill Scheidt, agronomy specialist with the University of Missouri Extension in Barton County.
CORN FIELD CHALLENGES
Already, black cutworms have been seen in some southwest Missouri corn fields.
“Right now the biggest concern in a late planting date for corn is the possibility of black cutworm feeding. Planting delayed because of cold weather can cause concern for high levels of cutworm feeding,” said Scheidt.
Black cutworms clip the corn plants off below or above soil level. If the corn plant is cut off at soil level, the growing point may have been damaged and corn may not be able to recover.
If 2-3 percent of plants are damaged at or below soil level, or if 6-8 percent of plants are damaged above soil level, an insecticide is justified according to Scheidt. A medium rate of Mustang Max or Warrior II is recommended.
“The planting date is not as big of a concern right now in corn. This year’s planting date should not be compared to last year’s average planting which was 10 days ahead of normal,” said Scheidt.
About 15 percent of the corn acreage in Missouri has been planted, that is about 15 days behind normal.
“If you are thinking about switching from corn to soybeans, costs and benefits of switching may not prove wise until planting is delayed until the last week of May,” said Scheidt. “If corn is planted, do not switch to a shorter maturity date variety.”
Scheidt says maturity levels in corn will move faster with increasing temperatures. Switching to an earlier maturing variety may result in corn pollinating too soon in the season.
“Cold weather should not damage corn because the growing point is still protected. When corn reaches 12 inches, a concern for frost damage may be possible,” said Scheidt.
Wheat is in the flag leaf to early boot stage. There is a possibility wheat in low areas may have been damaged if temperatures went below 28 degrees.
Scheidt recommends waiting three days to look at wheat. Cut open the stem and if brown discoloration is found on the wheat head, freeze damage is likely to have occurred.
“Lodging is the greatest concern. Wheat that is in the flag leaf to early boot stage is at greatest risk for lodging. If wheat does not stand up after the snow is gone and is lying completely flat on the ground, depending on the stage of the wheat, up to a 50 percent yield loss could be seen,” said Scheidt.
The further along wheat is, the more susceptible it is to lodging. According to Scheidt, if the stem has been broken below the growing point due to the weight of the snow, it will result in yield loss due to death of that stem.