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Crop watch

By Staff | Aug 16, 2019

August is half over with and the most important part of the cropping season is still in front of us. This is the maximum grain filling period which in the past few seasons has been mostly completed by now. With the three different maturities of corn crops running behind in planting date and even further behind in GDU accumulation, many fields will need help to complete their grain fill before any normal, ahead of normal, or even later than normal frost or freezing weather moves into the Midwest.

All of this sets the USDA up to be less than accurate when their Aug. 12 crop forecast is released on Monday. Unless their team has a climatologist with a perfectly functioning crystal ball and knows the rainfall and temperature patterns over the Corn Belt over the next two months, they know a lot less than we do as to crop size. So far the most accurate people doing their own multi-state surveys have actually stepped into the fields to see the effects of the early flooding and midsummer drought type conditions on ear and kernel size, pod number and pod fill.

Our house guests for last week drove through and observed the crops from Fayetteville, over to West Lafayette, and then back through Illinois to Ames. They saw a crop that was suffering from dry weather during a critical time, even if the NWS has shied away from calling this six week dry period a drought.

To the farmers and townspeople who are watching their crops and lawns brown, shrink in size, trees to begin to drop their leaves, and corn and soybean plants to either roll their leaves or flip them over by noon, we are in a very dry weather pattern. In parts of southeast Iowa and northeast Missouri, the crops haven’t had a good drink since through late June. Since then the areas in getting the good rains have been along and north of Hwy 3 up through central Minnesota and out into the Dakotas.

New bug issues

In the crop scouting and entomology world this is the time of year where we get to monitor the soybeans for aphids and possibly spider mites. We don’t typically worry about butterflies, and actually support the drive to increase Monarch populations. This year the central Cornbelt states have been blessed to be concerned about the thistle caterpillars, the juvenile or worm stage of the Painted Lady Butterfly. They have been prominent feeders of the soybean leaves in South Dakota the past few years with farmers having had to treat for them. This year their effects coupled with that of the burner herbicides seemed to reduce the energy state of the bean plants that flowering initiation dates were greatly delayed. Last week people driving along rural roads often drove through what seemed like Painted Lady blizzards, plastering their windshields. It is anyone’s guess as to whether or not a third generation will become a reality.

Otherwise the insects appearing in bean fields are leaf hoppers, very light aphid populations, thrips and occasional stink bugs along with confirmations of gall midges affecting bean plants in a few counties in western Iowa.


So when will the harvest of any corn or soybeans begin? It has already started as there is a seed corn field west of Iowa Falls that has already been harvested in. It must have been planted early.

A question that has been brought up among farmers, crop scouts and grain handlers at elevators is: if an early frost or freeze become a reality, as it was in 1974 and during the Clay County Fair sometime in the mid-80s; or the development of the crop gets slowed by cooler Aug. and Sept. weather and the corn barely makes it to black layer where it sits at 34 percent moisture, what is the best way to handle and manage the grain?

We don’t have enough cattle in the state or in each county to eat that much high moisture corn. I have heard the suggestion to let the plants stand in the field and combine them in the spring, but that would create a huge spring squeeze on tillage, fertilizer application and planting as we saw this spring. Do we temporarily store the grain in the big poly bags until the driers can catch up?

I previously mentioned the trial conducted at the Arise Research Station in southeast Illinois, where a tassel time application of CaSiO3 increased the internal leaf sugar level so it became frost tolerance until the temps hit the low 20s F.

Earlier this summer we had suggested Redox researchers do growth chamber studies to document what rate of Mainstay Si at various corn growth stages would protect the corn and bean plants down to various sub freezing temps. This could be very pertinent information for the many late planted fields this fall.

Banvel damage

The reports of additional drift complaints are again making the news in many states. The number of cases may be hitting an all time high, but the number of official complaints has not jumped as much. Officials are pondering this conundrum. It is highly likely the word has gotten around that once an official complaint has been filed eligibility for any federal crop insurance payment is lost. This year many growers may have fields that get damaged by excessive rainfall or flooding, drought, hail besides the Dicamba drift. Disqualifying any fields early could be costly. Or if the drift originates from a custom applicator they currently use and the managers don’t want to go through all the paperwork, restitution may occur with no official complaint filed.

Aaron Hager, a very good and thorough weed scientist at the University of Illinois, wrote a piece last week where he totally blew apart some of the bogus explanations as to why soybean leaves might cup. He completely torpedoed the suggestion it being caused by AMS. It is a lengthy and good read. In all cases it may be beneficial to gather samples from affected fields and stored for later lab analysis if needed.

I was looking in my old N Central Weed Science Society Research Books going back to early 1980s trying to find a research report where Gyles Randall, a weed scientist with the Univ. of Minnesota at Waseca, conducted a study where he applied stepped rates of Banvel and 2,4-D to soybeans at various growth stages. The information he compiled was fantastic, to the point that bean growers were asking how many ounces of 2,4-D they could safely apply to beans to obtain the same 2 – 3 Bu/A yield increase. It also pointed out how damaging Banvel drift was to soybeans, knowing no sane company was going to ever take the risk in that arena.

Field days

Aug. through early Sept. is an opportune time to attend the information filled field days in your respective areas. The one held by BASF west of Story City last week was excellent and was built around five different stories and led the discussions on challenges growers and CCAs face during the season. The day was perfect and the five stations provided pertinent information to the 200 people in attendance. In an era where resistance to herbicides and fungicides is a reality those who have to operate in both worlds are looking to innovative companies to deliver. Any group able to help farmers on controlling waterhemp we need.

This coming Tuesday is the Becks Seed Company field day down in the Colfax area. This is about the only seed company still doing widely located field trials on new products to see which ones consistently provide a positive ROI when used properly. Their testing can bring your attention to products you may not have heard about or considered using. Congrats to old colleague Jim Schwartz, Purdue grad and uber fan, on his leadership with Becks.

Yellowing corn

Starting 2 to 3 weeks ago lots of corn began yellowing. This has commonly begun in mid-July. There are several possible causes:

1. Enough N was lost during saturated conditions that the plants are now deficient due to no saftener being used or no sidedressed N being applied.

2: the shortage of N is causing the plant to have to scavenge for N and is denaturing the proteins in the upper leaves to capture more N. Applying a NH4 based slow release foliar N is or was the best preventative program.

3: Fungal or bacterial infections are affecting the root or stalk enough that no N can move thru the vascular system to the upper leaves. These decaying roots are no longer doing their job.

4: minerals move in the liquid or dissolved form into the root systems. When the ground is prohibitively dry those minerals are no longer dissolved. This year’s shallow, compacted root systems multiply these deficiencies.

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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