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Crop watch
July 8, 2019

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July 2019 has arrived and the 4th wa Thursday. And in keeping with a decades old axiom we need to ask "Is all of your corn knee high by now?" Unfortunately across the entire Midwest millions of acres of corn are barely ankle high. Similarly many of the bean fields that were planted recently are just as far behind. In fact there will be beans planted on Monday yet just south of the Iowa/Missouri border.

It is anyone's guess as to how they might turn out. Of course the NASS and USDA surveys will still plug in yields of 166 or so for the corn and 41 t0 45 BPA for the beans.

The USDA survey that was released last Thursday was one that only created lots of confusion instead of cleaning anything up. By Sunday night a staff member from a major university had his opinion circulated. In it he clarified that the survey sent to farmers only had two options for farmers to choose. Those were: 1. Already planted and 2. Intended to plant. There was no category to fill in for prevented planting expected or already filed. With the survey timed for mid June and that option gap that left 16.7 percent and 41.2 percent of the soybean acres that had not been planed yet in limbo. That is one huge information gap that will draw more and more attention from people that want a clear picture of the expected bushels to be produced this season.

Once that issue is clarified the caveats still existing is what sort of heat or drought stress will a shallow rooted crop have to survive. Then if late springs foretell of an early frost, how much of the crop will be left vulnerable? A lot of these late planted fields are projected to have a mid October black layering date.

Notables

It is surprising how fast the earlier planted fields have grown once the 80-plus degree weather arrived.

A number of the fields that were uneven and showed a lot of yellowing have improved, but not all. Does a farmer still wait to see if it improves or react already? There are many questions as to what is causing the problems. One good guess is that the anaerobic conditions of the root zone have not allowed the roots to expand and begin picking up residual nutrients.

I have received reports of a mix of Foliar Blend and O2YS have helped fields recover and begin growing as they should. The former is a sugar/mineral/plant stimulant mix that helps spur microbial activity in the roots. The later is a chitosan product that in university trials was found to regulate stomatal openings enough that it permits the plants to respire extra moisture, increasing O2 levels in the soil, and pulling in nutrition that had previously been unavailable. We saw cased last season in several soybean fields that it brought several stands back from the brink of death.

A high percent of the soybean fields need to be stimulated and manipulated to speed up their growth and increase the number of nodes and branches they will form. In past years we had assembled a workable program that did all of that with beans planted into mid and late June. Dollar-wise there is a big difference between 25 and 55 Bu/A beans. It may require an extra trip or two, but is worth it if the weather allows. We will be posting the late planting bean program at our website for people that may be interested.

People have begun to notice the appearance of the first fire flies. This typically identifies when the corn rootworm eggs have hatched. Can we hypothesize that a high percent of them may have drowned? This has happened in recent seasons. We will know in a few months.

Tissue sampling

With all the other tasks at hand remember to have someone pull representative leaf samples from several of your fields to have analyzed for mineral levels. Depending on what your yield goals are, those test levels may indicate what minerals may be limiting to your yields. Now or in the past three weeks was the optimum time to make any of those micro-nutrient mixes to your corn. It will shortly be the time to make applications to your soybeans, as having enough foliar to intercept the spray is essential to getting the job done correctly.

Disease issues

Most fungal diseases prefer a moist environment or wet leaf surface where they can gain entry into the leaf or root tissue. Plants that had tissue test levels low to deficient for Mn, Cu, Bo and Zn are most at risk of leaf and stalk diseases becoming problematic.

I had written earlier about scouting sweet corn ears in the grocery store down in St. Louis a few weeks ago and finding Clavibacter lesions on them. That news made it all the way to Beltsville, MD where USDA is housed.

This past Friday I was out near Grand Island in chest to shoulder high corn. By pulling off leaf number 2 to 4 right near ground level we were seeing the caramel brown color on a high percentage of the plants.

At this point the genetic tolerance, mineral sufficiency levels and weather stress will dictate which fields will have the most problems with this infection.

From working with an aerial pilot who offers a service through Air Scout we saw that an infected field will show up through thermographic imaging. The same temperature rise will show up when Eastern Corn Borers are tunneling in.

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

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