Late-planted corn north of Interstate 70 in Missouri is dead or dying due to lack of rain and scorching temperatures.
"As corn and soybean plants entered critical seed-filling periods this year, drought returned to some parts of Missouri with a vengeance," said University of Missouri Extension agronomy specialist Bill Wiebold.
To sustain high yields, corn and soybean crops need at least 1 inch of rain weekly, Wiebold said. That hasn't happened most of the past nine weeks. Some parts of the state have recorded no rain in seven of the past nine weeks.
Too late for rain to save corn yields
It's too late for future rains to save corn yields, said MU Extension corn specialist Brent Myers. Hope for rains to come to the rescue ended about three weeks ago, he said, and damage is widespread.
Myers said corn is showing signs of drought, including senescing, or drying from the top of the stalk down instead of from ground up, early ear drop, and a white cast to leaves and stalks. Corn may show a black layer at the base of the kernel, an indication that dry matter has quit accumulating, resulting in lower test weights.
In this year of weather extremes, rain and low temperatures prevented corn planting during the optimal period before June 1 and set the stage for disease development. Late-planted corn also didn't pollinate well probably due to the onset of drought, Myers said. Parts of the state have seen minimal amounts of tip back, where kernels are aborted from the tip of the corn in an effort to save moisture.
Wiebold said 2013's wet spring and dry summer presented a dismal scenario for crop yields. "Because drought stress occurred during mid-to-late summer, the yield component affected most will be seed size. Small corn kernels result in low test weights. Small soybean seeds may not affect test weight, but clearly reduce yields," he said.