Temperatures in Iowa averaged almost eight degrees above normal last week — after a week when temperatures averaged nine degrees above normal. That unseasonably warm weather has helped crops planted weeks later than normal.
Early reports indicate corn yields are higher than expected in parts of Iowa and Iowa State University Extension Climatologist Elwynn Taylor says the cooler-than-normal temperatures during the month of August are responsible for that. “Cooler than usual in August is almost always a sign of an increasing yield,” Taylor says.
Last year U.S. corn fields yielded about 122 bushels per acre. “We were expecting something near 150,” Taylor says. “Now it’s up to the mid-150s for the nation and for the state of Iowa well above that.” Commodity experts predict the world’s corn crop this year will be the largest ever.
If the government shut-down continues, the U.S.D.A. is unlikely to issue its scheduled crop report next week. In mid-September the U.S.D.A. estimated the Iowa corn harvest would average 162 bushels per acre. The record in Iowa was set in 2008, when corn yields topped 180 bushels per acre.
Despite a difficult growing season, most Iowa corn fields this year were spared infestation by a disease that was widespread as recently as 2011. Goss’s Wilt was confined to eastern Colorado and western Nebraska until 2008, when it spread eastward, infecting farms across the corn belt. Iowa State University plant pathologist Alison Robertson says modern hybrid corn varieties may be to blame for the resurgence.
“Because Goss’s Wilt wasn’t a widespread problem, the breeders didn’t pick up that these hybrids were very susceptible,” Robertson says. There are resistant hybrids on the market now, but the disease remains a concern. Even as its occurrence in the traditional corn belt has diminished with the dry conditions, Robertson says it’s spreading — and appeared in Louisiana for the first time this year.
“This disease is still continuing to pop its head up at places where it shouldn’t be popping its head up and so we need to whack the mole,” she says. Rotating corn with soybeans or alfalfa and then planting a resistant hybrid is a good recipe for preventing recurrence, according to Robertson. Goss’s Wilt was in 90 of Iowa’s 99 counties just two years ago, but she says two factors have protected corn in recent years.
“The fact that we haven’t seen a lot of it here in Iowa I think has to do with farmers growing more tolerant hybrids and also the dry conditions that we’ve had this growing season,” she says. The disease, which was first identified in western Nebraska, has been found as far east in recent years as Wisconsin and Illinois.
Reporting by Dan Skelton, KICD, Spencer/ Matt Kelley Radio Iowa also contributed to this story.