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CROP WATCH

By Staff | Aug 23, 2014

The Farm Progress Show is next week so this must be the later part of the summer. It’s funny how time flies when we have been having so much fun.

It seems that we never get our work done during the growing season, we just run out of daylight each day and call it quits after we get beyond tired.

I may see you at the FPS next week. I plan on being there at the Advanced Biological Marketing booth, 9312 in the Varied industries Tent, to answer questions and hopefully visiting with the tech people from many different countries.

Stop in if you get the chance.

The corn crop

I keep hearing that this is a record crop in much of the country, especially in parts of Illinois, eastern Iowa, and much of Nebraska, where rainfall amounts have been plentiful.

But if that is the case why have so many fields in central and western Iowa taken on such a pale ghastly appearance?

I remember that when the FPS was here two years ago most seed companies had pulled their signs two to three weeks earlier to hide any ownership to some of the fields that had been dead since mid-July.

In fact there were fields near the site that showed 25 to 50 percent hollow stalks after dying from various diseases. So I guess things are better this year, but still not back to what was normal before 2009.

The questions those factors generate is how will the crop finish and how will yields, harvest, and standability end up. In the fields that have begun to show the ominous top die back from anthracnose or Helminthosporium carbonum or whatever, it will be best to scout those fields on a regular basis to test for stalk quality.

Leaf disease symptoms have become noticeable in many fields. The different disease include Northern corn leaf blight, gray leaf spot, physoderma brown spot, eyespot, common rust and, last but not least, Goss wilt.

We have to wonder if the plugging ability of Goss’ is leading the plant to lack the ability to transport nutrients and water up the stalk as we have seen in past years.

It sure appears that the plants in those fields are cannibalizing themselves.

A year ago, a new disease appeared – red root rot – and seemed to affect several high-producing varieties.

Though a fungus called phoma was credited with causing the problem, the reddish color to the affected roots tended to suggest that fusarium was more responsible. Hopefully, the disease does not make a return appearance.

N management

Many of the bad fields are the ones looking the worst. Last season, yellowing many be the running out of energy by the declining plants.

It has to be making many growers consider making wholesale changes to their nitrogen management programs.

In soybeans

Many things are occurring in the bean fields that growers need to keep up with.

The first is that soybean aphids began to make a return appearance, albeit about two weeks behind schedule. We began to see increasing populations about two to three weeks ago.

A week later they were reaching the treatment thresholds along U.S. Highway 20, and now there are fields along U.S. Highway 30 needing treatment.

Now that the plants have reached R5 or later growth stage, all of the leaves present a good diet to the little sap-sucking insects.

With the beans being about two weeks behind in development and without being able to accurately forecast when the aphids will disappear, every grower much remain vigilant with their populations in each field.

Sudden Death Syndrome is also making a return in quite a few fields. Luckily the problem is not as bad as in 2010.

Many knowledgeable soybean people predicted the disease would appear again based on the saturated soil conditions of May and June.

Plants took on a yellowing color that never did disappear. This chimera disease works by scorching the upper leaves just after the last trifoliate leaf set fully extends itself.

There is not much that can be done except to pay attention to varietal ratings, reduce compaction in problem fields and examine herbicide usage of the implicated herbicides.

Application of micronutrients seems to have helped insulate fields from the problem.

Another disease that has been developing for about three weeks is downey mildew.

It began as irregular-shaped yellow flecks on the upper leaf surfaces that turned a more distinct yellow.

Last week the fuzz began to grow from those spots on the underside of the leaves. Some bean breeders tell that it can cause measurable yield losses if left unchecked.

In central Iowa there were people expecting white mold to be a problem.

This did not develop, likely because there was little to no rain during July, which is when the spores invade the scenesing flower petals.

It may be a different story up in Northeast Iowa, though July conditions were dry as well.

So the rule is to keep scouting your fields, especially the beans as there are still management steps that could be taken to save yields.

I may see you at next week’s Farm Progress Show.

Bob Streit is an independent crop consultant and columnist for Farm News. He can be reached at (515) 709-0143.

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