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CROP WATCH

By Staff | Jun 3, 2016

Well, so far the first six weeks of the 2016 growing season is over for many farmers, but for the growers in the western tier of counties who still have crops to get planted, progress is on hold.

Like we have seen quite a bit in the last years where planting time delays have become common, the growth stages of the corn and bean crops vary widely.

A big question among growers is what Mother Nature is going to deliver the rest of the season. Will a well-known meteorological service be right when it predicts a sudden switch to warm/hot and dry, or will the wildly accurate psychic weatherman who believes a very sudden shift is impossible due to the large mass of ocean water that still has to cool.

It sure makes marketing as clear as mud.

Crop stages

Cool weather with lots of constant cloud cover along with wet soil have been the rule in May in much of the Midwest. This meant that there were many fields planted to corn at the end of the first burst of heat and then took three to almost four weeks to emerge. This again showed there was value to get as many acres planted when the regular 10 days of heat arrived around April 11.

Although the first guys out are normally viewed as crazy, that is how it looks to me. Then we can almost count on the last week of April being cold and the first two weeks of May being wet and cold.

Through all the challenges many corn growers now in central Iowa have corn that is now in the V4 stage and ready to enter the V5 and later rapid plant growth stage. I was scouting fields about 85 miles south of Iowa City on May 23 and the early-April planted corn was in the mid V6 stage.

In this case, the low zinc levels detected via soil test was fixed with foliar applied chelated zinc and the low boron documented by tissue tests had been remedied by applying a portion of the planned MicroMix application being mixed with Halex.

It has paid off in that the corn was a good, dark green color and was looking great. Of course an observer could see that the chelating herbicide in the mix was creating a color change in the plants on the lighter soils.

One noticeable trait in a high percentage of the fields is that about two-thirds of the fields tend to be yellowed or bronze in color rather than a dark green. Will this be reversed after a few days of sun and heat?

If not growers may need to respond, and the best way would be to get tissue samples taken and get a mineral analyses run. Is the nitrogen actually short, is it a shortage of copper, magnesium and zinc, or a shortage of molybdenim.

If money is spent on the wrong proposed course of action the problem will still exist.

Remember that it is typically in the V4 stage is when post-emerge herbicides that chelate minerals are applied and corn fields can enter their ugly phase.

This is when knowledge about what minerals each group of herbicides is valuable in that can assist you in knowing how to respond if needed. If you notice appearance changes in your fields take notes about the soil types and topography where the symptoms are occurring.

Bean crops

Then comes a mention on the status of the soybean crop. It seems impossible to find any bean plants that have advanced beyond the unifoliate stage, even in fields that were planted more than a month ago. Luckily, most growers did spend a few dollars to put on the minimum seed-applied fungicides that have protected the plants as they tried to emerge in the saturated, cold soils.

Driving along U.S. Highway 163 past Des Moines, Pella and Ottumwa last week, it seemed that some of the fields were already showing the slightest color change to a lighter yellowish green as they have when saturated soils led to late-season disease problems.

Hopefully that is not the case, but it was a good indicator in both 2010 and 2014. If that observation is correct, what are your in-season management steps to stop that disease rather than let this Fusarium-caused root disease to advance?

If mineral deficiencies are manifested as diseases, then appropriate action would be to build those levels before diseases occur.

Early scouting

As you are scouting your fields, be sure to start by taking stand counts of each hybrid. Digging the kernels up and in any skip can help determine if seed quality or planter efficiency created the problem.

Remember that the normal corn rootworm eggs of 10 years ago used to hatch along U.S. Highway 20 around June 1. So if some of your fields have a history of CRW problems and you have been depending on traits or planting time-applied products, it will soon be time to dig to inspect for feeding damage.

Be alert to the fact that weather and soil conditions thus far have been conducive to disease problems in both major crops. And whether most corn growers admit to having a standability problem in their corn fields last year, the amount of volunteer corn in both bean and second-year fields suggests it was the year with the most dropped ears most people have seen.

We don’t want a repeat. Remember that fungicides are meant to control fungi. Using them against a bacterial disease is like going to a gunfight with a knife. Good luck if you do.

As more fields enter the V5 and V6 growth stages they get closer to the V8 to V10 or waist high stages. That is when the first lesions of whatever has been killing our corn crop early can be seen moving from ground level upward.

After working with two new products the corn growers who are aiming to keep their plants healthy and filling have to be proactive. We will be having them apply a one-third or one-fourth rate of a plant health booster called BioEmpruv along with a newer polymer penetrant/surfactant/wash off preventer (Argosy) to keep the plants healthy until September 20.

Those parts worked either last year in corn and different crops or where a similar strategy was needed to boost plant health. The product will be in limited supply and needs to be lined up now in order to make the ground rig applied V6-7 preventative application. Call Marv or myself for info on these.

Happy scouting. It is important to be thorough and careful in your observations and seeking answers.

Take a tool to dig with, a hand lens, scouting guides and a notepad to record all your observations.

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

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