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CROP WATCH

By Staff | Aug 7, 2015

August is here and with it is the knowledge that it is the make or break month for grain fill and final yields.

Will it be a month where we get average, or cooler-than-average daily highs and lows along with rainfall in the precise amounts timed to crop usage?

Or might it turn out below those expectations leading to less than record yields. We now hear different analysts talking of record yields in their small locale or sections of the state who just assume that every portion of the Midwest sees the same thing as they drive down the road.

When one talks to pilots who fly regularly or even an operator who drives a high-clearance sprayer, they get a different perspective and tell of a crop that is very uneven.

The fellows from Ohio last week related that they are hoping for and expecting their best corn to make 100 bushels. The pertinent question is when this will be reflected in the marketplace.

August is a long month where many things can happen that influence the final results. All we can do is manage the crops as well as possible.

If you are a dryland farmer you must manage the soil to catch and conserve the rain that falls trying to maintain the highest organic matter possible to serve as the moisture and nutrient reserve sponge.

Corn stages

Currently most of the corn is now in the late-blister to late-milk stage with some of the earliest planted fields and earliest maturity hybrids actually showing some denting.

That is to be expected. I did see some early planted 117-day corn last week that was 80 percent dented and had to try to figure out what was happening to it.

The kernel row number seems a bit on the low side while ear length seems about average.

The operators who made an early application of a phosphorous containing fertilizer or have high soil P levels are noticing 18 to 20 rows of kernels.

Did the saturated soils dilute the P flow into the plant enough to short the plant during the crucial V4 growth stage?

The ear lengths are still being determined as any stresses can cause tip kernel loss.

A few growers are already mentioning a higher-than-expected tip length. High yield growers who utilize late foliars and use the best biologicals challenge the notion that one must have .5 to .75 inches of ear tip showing.

Why not produce the photosynthetic capacity to fill all of those kernel sites.?

There have been lots of spray rigs operating and planes in the air the last three weeks zooming over corn fields.

Most were putting on different fungicides to control fungal-caused diseases related to wet conditions and lack of nutrition to maintain proper plant health.

The list of different pathogens is getting longer each year. This year’s new disease is called Physoderma stalk rot. Most of the pictorial guides include P. brown spot on the leaves and assumed it was a mostly benign entity.

That notion has changed as the stalk rot phase has been researched, detected at high levels in the state, and now recognized as a disease that can seriously affect stalk quality and harvestability.

The question that remains is what might have changed in the fields to allow a minor disease to ramp up its virulence to the degree to the 80 percent infected category?

In a quick trip to our state to the south where they had 7-plus inches of rain last week the brown sliminess of the lower 2 feet of stalk increased last week. Is this the new culprit?

Over the next few weeks we will get to see if more of the premature denting happens and if the plants stay as green through the entire season, or if they begin to ghost out weeks early.

In SE Iowa many fields are turning much yellower with quite a few of the bottom leaves beginning to abscise. Exact yields are still being determined based on kernel retention and depth.

In soybean fields

Many bean fields look pretty from the road, but how many of the observers have been out in the fields to count podded nodes and pods? The development of the crop is still behind normal with the node and pod counts being on the low side of normal.

It will be a few weeks yet before anyone can get a good handle on yield potential.

The first signs of SDS began appearing two to three weeks ago, even before the last trifoliates had extended. Where the soils were saturated this spring the potential is there for it becoming a noticeable problem.

Thus far good nutrition and the ILeVo product from Bayer seem to have helped mitigate the problem. Let’s judge the problem in about a month.

The other disease sure to make an appearance in the cooler areas will be white mold. It loves moist early July conditions if soil temps remain cool.

In many cases a late foliar-applied along with the planned R3 fungicide application can improve yields. Sugar and hormonal products included in the application can cause more flowers and pod to form and be retained.

R2 foliar or Y-dropped applied potassium and sulfur fertilizer have helped pod fill immensely in trials by high yield bean producers.

Kip Culler and Ray Rawson plus the few high-yield bean growers in the Midwest realized that late-season management is important and each extra trip buys them another 7 to 10 bushels. They simply figure out which elements are important to grain fill and might be short in the soil, then focus on those fertilizers.

New stabilizers

People always have to be alert to new forms of fertilizer or new biologicals that might help their cropping programs. A new stabilizer that is slowly making its way into the U.S. market is a one from BASF.

Is it the one that was tested at Purdue University years ago. At this time I don’t want to say too much or name it until I get things confirmed. Keep your ears open. Improved and longer lasting stabilizers are always important.

Also being tested are foliar-applied bacteria in the Azotobacter family known to fix nitrogen out of the atmosphere for corn plants that have been sprayed. Could they serve as the one or two planned mid-season application after 50 to 70 pounds were applied preplant?

There are a few trials of the product being conducted this year. So far the use of the hand-held Minolta choloroform meters have shown that the bacterial application took corn registering a level of 55 up into the high 70s, which is extremely high.

The $2,500 meters read the degree or greenness of a leaf and put a numerical score on each plant when the ear leaf is tested.

Lack of ECB

So far this season European corn borer population has been minimal. 1997 was the last high infestation year.

Undoubtedly the heavy use of Bt hybrids since then has helped lower the numbers.

Years ago the work of Bill Guthrie and Les Lewis at Iowa State University documented that the five-year cycles of high and low ECB numbers was due to rising and falling populations of two species, one fungal and one protozoa species, Beauvaria basiana and Nosema parasitized the larvae.

The schedule calls for 2016 to be one year before the 2017 peak.

We still must not forget about them.

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

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