Once a seasonably strong high pressure moves through the corn-growing region within the next few days, southerly winds are expected to return to much of the Plains and Midwest. A Low corn earworm migration risk accompanies these southerly winds, with risks initially in place in the Plains and far western Midwest Thursday night into Friday morning. The risk expands and advances east thereafter with most field sites west of the Mississippi River under a Low risk by Friday night.
As a cold front begins to push east through the Plains and western Midwest by late in the weekend, the Low migration risk area starts to shift to the east. Southerly winds are expected to continue east of the front and may result in isolated flights into especially the Great Lakes region and eastern Midwest. With most crops now past critical stages where insect damage could occur, only Low risks are predicted in the forecast despite a somewhat favorable migration pattern.