More insight on what might be causing premature corn die-down

Hopefully you're not seeing many cornfields like the one in the photo below, taken the first week of August in north central Iowa and first posted on our website Aug. 7. We've been asking crop observers for their diagnoses. Today, Iowa crop consultant Bob Streit offers some possibilities in his weekly field scouting report, which we include below.

August 14, 2018 — By Bob Streit

We have now hit the midpoint of August and it’s time to do an assessment of how the crops look and are projecting for yield, as well as deciding if there is anything else that needs to be done to them. Based on perhaps the weirdest growing season most of us have lived thru, it is tough to get a handle on how yields will turn out. The accumulated GDUs are about 300+ ahead of normal, but that may not apply given the fact that many fields were planted weeks later than usual. 

The big topic is the markets and how soon we might see the tariff disputes settled. We in the heartland don’t seem to have much say in the issue, but hope our grain sales to our normal customers can resume. As to soybean supply destined to be sold to China, it could cause a big increase in conversion of pasture land in Brazil and Argentina to be torn up and planted to be beans. Except in Brazil the usual time from breaking up the pasture or Cerrado, liming and fertilizing it, raising a crop or two of rice to get active soil biology activity going, and then planting the first crop of beans is typically three years. They can’t raise two crops of beans in one season due to problems with powdery mildew and Asian Rust. They also have major infrastructure and a few other problems.

On the national and environmental scene there was one court ruling and one EPA declaration that surprised observers.

The first was a declaration by the EPA officials that the staff of the company that made Lorsban insecticide had not presented enough evidence of product safety to keep the insecticide from having its label canceled. Currently all of said product must be gone within thirty days.

Most crop people and growers have been around the product since it is typically quite effective in killing insects, yet they hate the smell and being around it. It is an organo-phosphate insecticide, so qualifies as a nerve gas. The history of that class of products and its development is best described in books written about the German industrial giant, I. G. Farben, that began as an industrial dye company (Farben is the German word for colors). It is currently used in the Midwest and other growing areas to kill small bugs that live deep within a plant canopy, such as mites and aphids.

If it does disappear from use another substitute will have to be found that would be effective. Since researchers have evidence that there are now populations of pyrethroid resistant soybean aphids in the three-state corner of IA, MN and SD, the question of a replacement product will be asked. Was I surprised about his action? No. I was head of a national committee a few years ago where one person in the group was involved in its development and shared the company’s dark secret with two of us. The best course may be proper plant nutrition that allows the bean plants to process any simple sugars into Carbohydrates and any NO3-N into proteins. 

The other action was the verdict rendered in the DeWayne Johnson v. Monsanto trial that was held in San Francisco. The issue was Mr. Johnson’s constant exposure to one of the company’s product in his job as a school groundskeeper. After being repeatedly exposed and sometimes doused with the product he came down with a serious rash that was diagnosed as Non-Hodgkin’s Lymphoma. After about four weeks of trials and jury deliberation the chemical company was found negligent in warning applicators about any harm that might come to them if they were exposed to the product. The jury awarded Mr. Johnson $289 million, even though a lot of internal documents forced out via the FOIA were not allowed into court and presented to the jury. An acquaintance has possession of those documents and has summarized their findings. It is an interesting batch of documents and summarizations. These facts should be coming out in future medical review papers.    

Starving corn in north central Iowa,
early August

Observations about the Crops

I was thinking about what I have all seen during my travels the last ten days, which took me thru SE Iowa on my way down to the Kahoka, MO area, up to Rock Rapids way in the NW corner of IA, over to the Atlantic area to look at green snap, down to Greenfield on Saturday, and over into eastern IA. This includes looking at quite a few fields in central IA as well. I could be facetious and say “I wonder when the frost hit” because about 30% of the fields look like they have been frosted, with the plants white or brown and the ears tipped down.

About 50% contain sections that are brown and sections that are green, with the former also having the flipped down ears. Then the last category includes fields that are still a healthy green and the ears are still filling. Now back 30 years ago the biggest threat to the corn was having an early frost that threatened to kill the still green plants. What is going on to cause the plants to die about five weeks ahead of time? And right next to the dead fields are fields that remain green. Those make up about 20% of the fields.  Lack of moisture is not the total answer. 

Anyhow in last week’s USDA crop forecast and the current stage of crop progress, I did not see a category that included 30% dead, but not having reached maturity. This is not going to be good for final yields or standability. I have not been in the eastern Cornbelt, but talked to a knowledgeable crops person from Illinois who related that a sizeable portion of their good acres were hit hard by Bacterial Leaf Streak/stripe.

He estimated that it was shutting the plants down about three weeks early; meaning about one third of their fill days may not materialize. Then a sizeable percent of the corn and bean crop in MO and KS has been torched with extreme heat and dryness. In talking to farmer friends who drove down to KC last week they told of all the corn being dead and soybeans being mowed and windrowed before being baled for cattle feed. I drove past ponds that are close to drying up and cattlemen are already selling off cows. How will their fields average 131 Bu/A if 40 miles into the state from IA the corn is being guesstimated by insurance people at 45 Bu/A and it gets worse as one moves south?  

In a conversation with a very wise retired Purdue plant pathologist, he described what we might be looking at is a disease and plant weakness complex. The plant's vascular system has been compromised, and is getting clogged up by bacteria and another entity. This exaggerates the damage done by lack of moisture and a shallow root system. Then the thirty days of saturated soils led to a major loss of nitrogen and a huge deficiency in the plant as it continued development. Now as it is trying to fill the grain, it is denaturing the proteins in the upper leaves as it scavenges for more nitrogen. It is out of energy.

In 2014 when the farm progress show near Boone, IA occurred at its normal late August date, about 50% of the corn plants were brown by Aug 18 and about 90% were brown by the show date. About half the plants and varieties were so lodged they canceled the harvest demos. Here we go again.

The well managed fields that avoided the standing water, had good drainage or avoided the huge rains, where they were able to apply in-season N along with effective stabilizers, and were able to maintain good nutrient levels in the plants are the ones that are green and still filling ears that remain upright. At times fungicides helped, but the major issue was bacterial.

An Upcoming Field Day

Early next week, Aug 20, a number of us ag people will be hosting a field day 4 miles west of Guthrie Center on Hwy 44. There will be people discussing N management, soil health, biological mixtures, polymers/stabilizers/extenders to make fertilizers more efficient, Si use in plants, new safe pest control programs and products, one surprise new product, and lastly a microbe to combat heat and drought stress.

The biochemist who developed the BioEmpruv is also on the program. There will be 12 different groups of presenters, so the pace will be fast. The president of the company that developed the endophytic stress fighting microbe will be on hand to discuss his product and results. He can be viewed on his U-tube Ted talk discussing symbiosis. 

Most growers who attended our March 12, 2018 meeting in Ames said it was one of the best and informative meetings they have ever attended. This should be as good or even better. After the in-the-shed portion of the program attendees can then go through the plots and likely see the best corn plots they have ever seen filled with the most impressive plants they have seen. In the past two seasons the corn stayed green until Oct 20 when the grain was harvested at 18% moisture and produced the highest nutrient content grain ever as tested via the X-Ray defraction scanner. 

In this work our goal was to identify new and safer products to manage or avoid residue, weed, insect, fertility or disease issues in crops while helping to restore soil microbe populations and produce crops with lower input costs per bushel. We suggest pre-registering to guarantee you will have a meal to eat. Bring your lawn chairs. RSVP to This email address is being protected from spambots. You need JavaScript enabled to view it..