Although the large acreage reported at the end of June shocked the corn market, it almost goes without saying that good yields are still important to end up with a large crop, said Emerson Nafziger, University of Illinois Extension agronomist.

"While guessing at crop prospects before we see many tassels is always a little dangerous, we now have some idea about the physiological state of the crop as it enters the most critical yield-determining part of the season," Nafziger said.

The latest report from the National Agricultural Statistics Service (NASS) indicates that 8 percent of the Illinois corn crop was silking as of July 3, behind the 21-percent-average of the past five years, but set to increase substantially over the next week as the crop planted in early May begins to silk.

"In our planting date study at Urbana, a 109-day RM hybrid planted on March 31 silked on July 3, and the 113-day hybrid on July 5," he said. "That's after about 1,400 growing degree days for the early one, and 1,450 for the later one. The May 5 planting will probably silk later this week, at about 1,300 or 1,350 growing degree days."

Most of the crop — where there hasn't been serious water damage — has benefitted from the dry weather and sunshine over the past two weeks, he said.

"Root systems have grown well, and the good rate of crop growth shows that roots are tapping soil water beneath the top few inches," he said. "Now that the surface soils are drying out, roots are actively taking up water from deeper in the soil, and this is keeping the plant functioning well."