Farm Progress Show visitors ask consultant Bob Streit: What hit Iowa corn?

Here's an early-September fall field report by Boone, Iowa crop consultant Bob Streit. There were many out of state and out of country visitors at the recent Farm Progress show. A common question from them was: "What has happened to your corn crop?"

Sept. 3, 2018  By Bob Streit

Early Dying Corn

The non-Iowa visitors were expecting green and healthy corn. What they saw were a high percent of brown fields with the ears flipped down. My response was that it was not natural, but it's now the new norm. The full explanation took a few minutes and it created some puzzled looks. I typically said that the poor state of corn plant health was a bit worse in 2014 when the harvest demos were canceled due to the severe lodging and it was embarrassing to the seed companies.

At some time in the future the corn growing industry needs to come up with an answer that ties it to mineral nutrition rather than just recommend a fungicide application. A few updated and observant crop scouts have been noticing a color change in corn plants in the July 10th to 15th time frame.

We are seeing in plots that a 4 oz. per acre BioEmpruv in-furrow application at planting time creates a much healthier corn plant and stalk. Three years of work by Dave Schwartz and his crew at his Guthrie Center plots have shown this boost in early disease control can help produce monster corn yields. If this product that supplies minerals and healthy plant growth promoting compounds, plus a fermentation compound is keeping the plants green and free of bacterial attack, then the primary problem is bacterial in nature and not fungal. The two families of pathogens can work together in attacking plants as they gang up.

Here's another observation: A number of growers who applied both the Mainstay Si calcium product and the BioEmpruv typically had near-perfect plant health and resulting large ears with no expense for foliar fungicides.

In a related project, a number of us are gathering plant samples from across several states for testing with the AgDia CMM kits.

Based on field observations and kernel counts, yields will be very good from fields that have remained green and received decent amounts of rain. The divide between northern and southern Iowa is crazy this year. North of Hwy 30, the problem was too much rain. South of Hwy 30 it was too little rain after July 1.

Stalk Quality

Charlie Hurburgh, the Rockwell City native and ISU grain quality specialist, warned producers in the audience at the progress show that stalk quality this fall could be poor. The stresses on the crop this season were severe and the lack of moisture during July and August will be manifested as stalk rot. Corn growers should be touring their fields and walking in to perform the push test on plants in different areas.   

One other factor to know is that the Clavibacter bacteria produces amalyse and cellulosic enzymes. This means the Goss’s bacteria produce compounds that dissolve cells in the stalk and shank. When you walk into freshly combined corn fields where the stalks still contain moisture and sap, you can detect a sour, vinegar odor. This is that enzyme odor. They use the same enzymes at ethanol plants to dissolve the kernels more completely to boost ethanol yield per bushel of grain.

Make note that early corn harvest in TX and OK began a few weeks ago and there are reports that some mycotoxins have been detected.

Residue Management

As harvest approaches, the topic of residue management comes up. What might be the optimum way to handle the residue from high yield corn, especially if you have highly erodible soils in your fields and/or need to raise second year corn?

So far the BioDyne 501 microbial mix has done a terrific job of decomposing the stalks when applied in the fall. The earlier and warmer the temps when making the applications, the better as more sugars are available. We saw last fall at Guthrie that applying the product on 350 Bu/A stalks behind a stalk shredder caused the residue to decay at such a rate and improve the moisture infiltration rates that the fields could have been planted by mid-February without using trash whippers. 

 SDS in Soybeans

In the last three weeks the signs of this Fusarium vulg. infection have been appearing in more fields, especially where saturated/low oxygen/compaction conditions occurred earlier in the year. The worst areas so far have been appearing north of Hwy 3 where the rainfall amounts were historic thru much of the season. The yellowish tint to the foliage early in the season hinted there would be late-season problems. So far the blue snot on the roots has been tough to see. I will comment more next week on treatments that could have been applied to the seed.