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By Staff | Aug 12, 2011

This is a very crucial three week period as the heat, sunshine and amount of rainfall determine how well or poorly each kernel or pod fills.

Everything everybody in ag has worked for since last November comes down to this. We have to hope and pray and do what might be needed in the final days to insure success.

A major crop report is scheduled to be released shortly. Everyone can already point out why it will be so inaccurate. Reasons include:

  • That all of the droughted acres down south and drowned acres along the rivers – prevented row crop planting in the Dakotas – and mudded-in acres out east are not being accounted for.
  • That the counting process is not geared to accurately assess unfilled pods or shallowly filled kernels.

It will take time and perhaps some early harvest results before we can truly assess the size of this crop.

Currently the one person that I have interacted with who understands Goss’ wilt has been in many fields in the corn growing parts of the U.S., understands mineral deficiencies and their link to poor plant health, and knows how to look at plants and ear size is coming up with a crop size estimate way lower than any trade guess.

What do we do if the corn crop size is 1, 2, or 2.5 billion bushels lower than normal?

Crop progress

How the corn crop looks from the road and how it looks six or more rows in is typically very different.

During the 98-degree days anyone who had the horrible job of going into those fields found out that the temp and heat index inside those fields was much hotter than on the outside.

We can see the effect now in many production fields and reportedly in seed fields as erratic pollination is found quite commonly.

We are also seeing that kernel fill is much shallower than normal and the kernels in many areas are beginning to dent weeks ahead of schedule.

Typically this indicates that the normal 55- to 60-day period from silking to black layering will be reduced by a substantial number of days.

That is all a function of excessive heat, both daytime and nighttime and moisture stress.

The weather bureau facts have been circulating among commodity advisors for a week or more. Most summaries show that from Omaha to Toledo, OH., the July daily temperature averages were among the three warmest on record.

In addition, the July daily low temps in Des Moines were the highest ever recorded. There was an excellent story written in the University of Nebraska IPM newsletter that described the physiological consequences of those high temps. It is a great informative piece and should be read.

More on Goss’

The issue of widespread Goss’ wilt being found in corn could also be a very large story with a big influence on final corn yields.

Most farmers still do not know what to look for with this disease, or have not learned that there are several different phases and symptoms of the disease.

The long time, semi-retired queen of Goss’ believes that there may be eight or nine different races.

The symptoms range from having desiccation of the top four or five leaves on the plant, or having the second ear become rotten and very stinky, or having mottled caramel to black lesions on the lower few internodes that moves up and rots the ear, cob and grain.

We know the old version of the disease was solely clavibacter bacteria caused and remained mild and in a small area of Nebraska and Colorado.

Now it is all over, causing scorched leaves, has become very virulent and invades quickly.

This lends a lot of credence to a second microbe being involved, especially since one can be seen under a scanning microscope.

Several of us have spent quite a bit of time examining the affected fields.

West of Storm Lake the major symptom seems to be scorched leaves. East of there both the scorched leaves present, as well as the bottom internode discoloration, black slime and bad smell.

At times, when we scout for it we end up passing around infected tissue, that smells like over-ripe road kill to compare its wretchedness.

A few of the treated fields have now been sprayed five to seven days ago, and the smell, sliminess and advancement of the symptoms seem to have disappeared.

Solving the problem long term could be tough, especially if the causal organisms do survive in foxtail and other grass species.

Since the organisms survive in the soil, every time the plant evaporates water the transpiration pull allows re-infestation.

What we have seen is that fields that have received any micro-nutrient application look better than those that received none.

Those that received two to four look better than fields that received none.

There are families of corn genetics that were supposed to be susceptible that are getting clobbered.

There are lines that were supposed to be tolerant or semi resistant that are showing lots of spotting on the stalks and ears.

The number of traits that have been inserted also seem to influence the degree of infestation. Having applied any surfactant to the plants seems to have increased the level of infection.

A month ago I asked readers if they each had their action plan in place if Goss’ hit and if they had done everything to improve their chances of meeting their yield goal if the disease appeared again.

This sounds like a lot of extra bother, but it may be how we have to operate the next few seasons.

Catchy slogans, expensive marketing campaigns, or denying the problem are not going to be the solution.


If you have not done so yet, remember to check your bean fields for yellowing leaves near the lower part of the category. This would be septoria leaf blight.

Also in fields now along U.S. Highway 20, scout for aphids. The insect populations are increasing now with quite a few fields exceeding the threshold.

Most of the soybean grain fill still has to occur and what you do yet can influence how good the fill becomes.

If you have the chance to go flying, now is the time to do so.

Call a pilot in your area.

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

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