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CROP WATCH

By Staff | Aug 19, 2011

So how much of Iowa is due to get the needed amounts of rain during the next two weeks?

Until now we have sat back and watched a limited number of fronts move by to the north or to the south.

We in farm country realize the ramifications of what a much lower-than-expected corn and bean crop will do to food prices and overall ag trade, both in the U.S. and importing countries.

Coupled with cropping problems in China, Russia, Brazil and parts of Europe, our big supplies of food may be gone.

Typically everyone depends on the three ‘I’ states, southern Minnesota and Nebraska to raise a high percentage of the corn and beans.

This year the production capacity of all of these states has been diminished, even where irrigation was being used.

The state and county fair season has come and gone. Those always require lots of work at the local level to organize and make successful. They can also be rewarding in that they teach impressionable teenagers the value of starting and ending a project that they are interested in.

Such lessons last a lifetime and often help to shape what that person becomes and achieves. Most of us were in 4-H as we were growing up and are thankful for the many club leaders and country Extension staff members that worked toward having such programs.

After the state fair ends the major event remaining is the Clay County Fair scheduled for early September.

Rainfall, temperatures

Most parts of Iowa and Nebraska are still feeling the lingering effects of La Nina-caused dry weather and excessive heat.

According to Elwynn Taylor on Tuesday, ocean temperature charts seem to indicate a movement back toward another La Nina event rather moving toward El Nino and better rainfall patterns.

We just have to hope for a stray cold front to march across the states and dump 2 to 3 inches of rain on us soon. A series of 1-inch shots would also be very welcomed to add weight to corn kernels and either start or continue to plump up the bean pods.

With it cooling off, more crop scouts and farmers are returning to their fields to walk more than a few rows in and inspect the plants for diseases and the ears for degree of fill and kernel depth.

For those doing this after a two-week absence what they are seeing is sometimes shocking. Where did that 200-bushel-per-acre yield go and what is next?

What looked like decent pollination now has morphed in ears that have tipped back one to three inches.

In addition the kernel depth in many areas is only about half of what it should be.

The U.S. Department of Agriculture survey seems to pick up on part of this, but seems to be making reduction in crop size estimate in thirds so as to feather out the market and consumer impact.

Let’s see how the Pro Farmer and other crop tours do as far as detecting these weather- and disease-induced effect on the major crops. Those will be taking place over the next two weeks.

Even then it may be too early to form accurate yield projections since many fields of beans will still be trying to turn any late rains into grain.

The fields that have maintained the best are those where the operator has done his or her best to promote a deep soil with rich biological activity, used conventional chemistry, planted disease tolerant varieties, perhaps applied biological inoculants, and followed a tissue testing program along with subsequent micronutrient applications.

Disease observations

One thing that wise and, hopefully, prosperous growers keep in mind is that this current state of agriculture – where crops just “up and die” in the fields as they have in 2009, 2010, and now 2011 – is not normal and should not be happening.

It was interesting to read a story where a representative of an Iowa-based seed company was being interviewed about how corn cultural research was being conducted.

The interviewee told how they were experimenting with 40,000 and higher plant populations as a way to boost yields. In the accompanying pictures, all of the corn plants had the characteristic black lesions near ground level that have become indicative of Goss’ wilt.

None of the printed articles mention such lesions, but that is what has been showing up in the fields in the last three to four years and has been damaging to yields and standability.

Remember that most fields’ tissue testing is showing as deficient in manganese, magnesium, copper, zinc, boron, molybdenum, and others micronutrients.

This is having a negative effect on plant health.

I had the chance to fly over central and north central Iowa late last week to see the crop from the air.

The bean crop does not appear to have been hammered by SDS as it was in 2010.

All of the lighter soil spots are wilting down quite badly. The corn is a different matter in that different diseases are attacking quite a few fields.

Of primary importance is Goss’ wilt, which, with its different races, is causing different symptomology.

The first and most noticeable is that the top three to four leaves can turn gray and wilt down. This is happening on maybe 5 to 10 percent of the fields that now look like they have been napalmed.

In addition there is another set of fields that contain numerous 20- to 50-foot diameter spots where the corn plants have died. The cause seems to be either Goss’ or a bacterial stalk rot, maybe combined with the micro-fungus.

Tests done using an SEM indicate the latter. Fields that showed top leaf symptoms last week are generally dead fields this week.

Thus something is acting in a very rapid fashion.

Several fungal diseases are also becoming apparent.

Gray leaf spot, anthracnose, fusarium, Northern corn leaf blight, and eyespot are also affecting corn. In the last week anyone driving by the fields can notice a huge shift toward lighter-colored plants that are responding to the mixture of environmental stresses and poor plant nutrition by starting to senesce, or yellowing, and calling it quits.

This would be the third or fourth year in a row for this to happen. The yield drop-offs that have resulted have not been kind to most farmers and farming operations.

Those who applied one or more applications of micronutrients are noticing a boost to plant health and often no signs of fungal diseases.

A few growers and agronomists apparently have not gotten or absorbed the information that fungicides are not effective against bacterial diseases. In fact, the addition of the surfactants in such mixes can open the plant up to more bacterial problems.

Looking at plants that were sprayed with any of the innovative mixtures to control the bacterial invaders over the past 10 days seems to indicate that the diseases seem to have been stopped.

The slime, advancement of the disease and the offensive smell seem to have disappeared. Let’s see if the length of control is as long as last season.

Aphids

Don’t forget to continue scouting for aphids. They have now moved onto the larger leaves and the plants grew into the R5 growth stage.

As the dry conditions persist, the economic thresholds should likely be moved downward as the sap supply to fill the seeds becomes more valuable.

Curative action

For the farmers who are watching their fields go downhill and threaten their cash flow projection, their thoughts have to be advancing to “what should I do for next year?”

That is a very good question that begins with research. We likely need producer group-funding for at least one or two projects studying these diseases at ISU. Then the involved people need to look into all possibilities of what might be causing the problems.

One area of exploration has got to include the possibility that the balance of good and bad microbes in the soil has been upset and the normal populations of beneficial ones has been greatly lowered.

If we had a way to test soil samples to document a population shift along with guidelines on what to do to shift it back to normal, along with an available supply of such beneficials that could be seed- or in-furrow applied from commercial firms, that could get us back on track.

That is a possibility that several of us are exploring and will be sampling for this fall. When you or your crop advisor is pulling soil samples, separate off enough soil from each batch to drop about two cups of the sample into the freezer for possible testing this winter.

From what we know the accuracy and cost of such testing will be reasonable.

May it rain on everyone this next Sunday and/or on everyone’s parade. We need it.

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

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