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By Staff | Aug 1, 2018

August is here and the results from the first two thirds of the growing season are very mixed, depending on latitude within your region, drainage capacity, and topography.

People that travel a lot within the Midwest say it is a good crop coming on with areas expecting perhaps their best corn yields yet, but that enough warts are showing up that they feel the govt. estimate on the size of the 2018 crop is too large.

In my travels across the state and into surrounding areas the problems with lost nitrogen, untimely and either excessive rain or lack thereof, will limit production, and lost kernels will keep a damper on yields this fall.

About this time of year we always seem to be looking into the rear view mirror at the summer because the signs of the approaching end to the growing season are appearing, and we recognize that harvest is inevitable, and then it snows. While we get to enjoy the flowers, fresh veggies from the gardens and other guilty pleasures over the next four to six weeks, September will be here before we know it.

Crop producers are still scratching their heads over the markets, recognizing that market manipulations, tariffs, and IP protection violations by other counties often placed them at a competitive disadvantage to producers in other countries, and needed to be changed. But is there enough recognition that food is often too cheap in the U.S. regarding the farmers’ share, and expected to remain so by government agencies and consumers? In what other industries do producers buy retail yet have to sell at wholesale prices? Let’s hope that we see a resolution to the soybean tariffs so years of efforts by producer groups do not get eliminated.

The corn crop

The heavy dews of late June and early July seem to be less constant and the increase in new fungal lesions seem to be subsiding. There seem to be large differences in the severity of the different leaf diseases seen in fields. I had been seeing quite a few that three weeks ago seemed to be on the verge of needing fungicide or bacteria treatment, and now that increase in infections based on having a near continuous water film on the leaf seems to be over with. So I have been recommending fewer applications for the control of leaf diseases in corn fields. Remember though that deposition of dry matter does not begin until the plant reaches the brown silk or late blister stages.

Remember that all of the USDA corn yield estimates are likely made with the assumption that the fields will not run out of nitrogen. When driving the roads and walking into the fields it is very apparent that the saturated soils soil during June caused a loss in applied nitrogen. Not enough of the nitrogen applications included an effective stabilizer and it is apparent that not all the stabilizers did an adequate job of keeping the nitrogen where it was applied. This will have to be recognized and rectified in future years as in next year, as we never know when the next season will have prolonged wet periods that put the nitrogen system at risk. Remember that the stable of good nitrogen stabilizers is expected to have a good new one added for 2019.

When scouting fields the last three weeks I have been using my Minolta SPAD meter to take measurements and recording them for the grower. The instrument reads the degree of greenness in the leaves to infer the level of nitrogen and chlorophyll. The readings are given on a 1 to 80 scale with bigger being better. If the readings get down to 50 or below, yields will be reduced. If they remain in the mid to high 50s or above the plants have enough nitrogen to produce maximum yields. I checked plants on Sunday from fields that were somewhat yellow and they registered in the 40 to 50 range. The quite yellowed fields are under 30 with plants in the worst spots registering around 25.

Too often the equipment and budget to remedy the situation were not available. Buying one of the less expensive SPAD meters to permit growers to do their own monitoring of their fields is something that needs to happen.

The acres affected by greensnap also seem to be increasing. So far the worst episodes were in west central parts of the state, as in near Atlantic and Avoca where levels of breakage up to 75-80 percent of broken stalks were seen. Several of us will be making counts in those areas where damage was severe and the stalk strengthening mineral silica was applied. Counts will be made and drone footage will be shot, because until now this problem typically shows up in several areas each year and no one could do much about them. Back in late 80s and early 90s a young plant breeder at his Spencer breeding station used old water heater tanks sliced in half with the ends torched out to attach to a high clearance sprayer boom to purposely break stalks to find which families had greensnap problems versus which ones could tolerate strong gusts of wind. He concluded low Si levels were the main cause of the problem. There are other sections of the state where such damage has also occurred.

Tip back on corn ears has been minimal this year, though pictures from ILL circulated on email messages show ears with 2 to 3-inch of tip back. Any issue with sunlight, cooler daytime temps or reduce sunlight, lack of proper nutrition, or lack of rain that reduced sugar production can lead to kernel loss.

Another noticeable item is the rapid wilting of leaves and plants after just a few days without rain. Many root systems were affected by saturated soils and grew very shallow.

The brownish slime layer and leopard frog appearance of the leaf sheaths on the lower internodes continue to expand, meaning the bacterial infection is continuing to move into and multiple internally in the plants. There is still time to spray and stop the blockage expected to occur and shut the plants down in three to four weeks. Fungicides are now effective in controlling this problem.


Again there are large differences in the appearance and yield potential of different fields. From plants that have stayed short without much branching to plants now heavily podded and closing the rows. There is still a month in which new pods can be formed and develop into filled pods.

The highest podded node count I have seen so far has been 20. Those were beans planted earlier than was recommended. One development that I have to check out is a new microbial and mineral mix that warms the soil about 15 degrees to permit earlier planting. A very knowledgeable ag person we visited with on Sunday night was heading over to the Baltic, South Dakota site to apply a product to soybeans to limit White Mold problems on their max yield plots. Growing a thick healthysoybean category is also conducive to white mold infection and curative programs for that may not exist in the current arsenal. Time will tell if two new products will be effective. At this site high yield advocates provide the recommendations as to steps and products to use in their quest. Input cost will included in the final posts so net return amounts will be given.

Bug issues

The extension IPM New Reports continue to tell us that aphid populations in Minnesota and South Dakota remain light. I was up north of Mankato last week and it was tough to find any of the little beasts. Apparently the buckthorn has become a major invasive plant in South Dakota, and it serves as the overwintering host for the aphid. They speculated after the cold winter that subfreezing temps during the April snows may have killed most of the overwintering eggs/adults after they had hatched and begun to feed. That thought must be accurate.

I also spoke with a local aerial applicator. Typically when the wings on their spray planes return with sticky green slime on the front edges they know the aphid adults are getting carried into the state by the breezes at 500 to 1,000 feet. That was beginning to happen last week, but was not as thick as in previous years.

The August 20th Guthrie Center Field Day

The guest list for the planned Aug 20th field day at Dave Schwartz’s Verdesian Life Science’s field days is getting longer each day. We got confirmation over the weekend by a few of the invited presenters, so the knowledge base by that group of people should be very deep. The focus will be on soil and plant health plus the innovative products that will aid in plant nutrition while also improving disease control. Improved grain quality with higher nutritional content is the expected result from this work.

We will be posting a copy of the invite on our website for your viewing along with the resume of each presenter.

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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