According to Bob Streit, of Ames, crop consultants like himself are not optimistic over the coming harvest.

There will be a harvest, but the overall yields will likely be a disappointment, he said.

"People who have been walking the fields," Streit told Farm News Tuesday, "are seeing too many blemishes to say there's a good harvest waiting."

The reasons? Take your pick among several.

Streit said the prolonged cool, wet weather, has not not only caused row crops to be about 10 to 14 days behind in maturity, but has activated diseases much earlier than usual and, in some cases, unleashed diseases that are not generally seen in Iowa.

Add to this two destructive hail storms - the Aug. 9 storm that drove egg- and golf ball-sized hail in a five-mile swathe from Sioux City to Waterloo, and another hail storm earlier in the northeast corner of the state - plus the usual yield-robbing insects and one can imagine that the overall Iowa harvest will be well under a record.

John Holmes, Iowa State University field crops specialist in Wright County, said he has some hopes for a fair corn harvest if the crops doesn't freeze, but is not positive about the overall soybean yield. "Soybeans will be down because it was cold in July and August," Holmes said.

Streit said there will be some fields that will produce record numbers for their growers. "I have a client that will get 120 bushel beans," Streit said. But that is one grower.

As a whole, he said, Iowa's northwest and southwest crops are looking to be in the best shape.

Westcentral and northcentral Iowa went six weeks without rain at its crucial growing time. Southcentral was planted too late, with saturated soils. Southeast has been heavily challenged with leaf diseases in corn. Northeast crops had hail and are 400 heat units behind normal. "It's a battle out there," Streit said of farm fields.

Streit had just returned from the Iowa Falls area where he said corn was aborting the top 20 rows of kernels, about one-third of the ear, due to a lack of heat.

"Corn is designed to make sugar," Streit explained. It takes the combination of photons from the sun, plus micronutrients from the soil and carbon monoxide and converts that into sugar and fills the kernels. Because the crop is lacking heat units, the plant determines it cannot fill all of the kernels.

"The tip rows are the runts of the litter," he said, meaning they get fed last, if the plant can manage it.

He also produced a corn plant that showed the beginnings of stalk rot from anthracnose, a fungis that kills plant material. "We're on course to have a fair amount of stalk rot this year," Streit said, showing the plant. When asked where in the region he sees the infection most, he answered. "It's everywhere. We saw stalk anthracnose in July. That's very early."

Other leaf blights also popped up early this year such as gray leaf spot and corn eyespot, again two affects of cool, wet weather.

"In fact eyespot is historically a Wisconsin disease," Streit said, "but this year, we've had Wisconsin-like weather."

Aphids

Then there were the aphids this year. The numbers were not as bad as last year and they arrived three to five weeks late this season. Because soybeans were behind in development, Streit said, the rows were still open enough to get one good spray application for aphids, as well as a few other applications. "Last year, those who did not spray for aphids, it cost them 24 bushels" per acre, Streit said.

Managing nutrients

Managing nitrogen that has been a big challenge for producers, especially in corn-on-corn fields. Because last year's residue could not get properly tilled because fields were too wet, there was a substancial amount of residue this spring.

"Plant breeders have been breeding for tougher stalks for better standability," Streit said, "and those stalks did not deteriorate much during the winter." As a result, he said, residue took the first 120 pounds of nitrogen per acre before the new plants got any.

In addition, any innoculum, the spores from fungal diseases, that existed in the 2008 residue was still active and infected the 2009 crops, which is blamed as the primary cause for the early leaf blights this year.

Contact Larry Kershner at (515) 573-2141, ext. 453, or by e-mail at [email protected].