We are in the last full week on July. Now through mid-August is typically the hottest and driest part of the summer. It is also the time when most of the sweet corn comes into full production and we get our fill of this tasty crop along with watermelons which are grown in places where sandier soils produced the sweetest fruits. Our first sweet corn planting is just filling out the kernels and will be ready in a few days. Planting #2 and #3 will follow. If you can pick up either the Muscatine or Greg Heldt’s Black Diamond watermelons of Yutan, Nebraska sandy loam-based soils, give them a try as they are superb. Several grocery stores, including Fareway, have been stocking them recently. We personally go thru nearly two melons a week here, as eating cold melons on a hot day seems to cool a person off.
Just as Simon Atkins predicted four months ago, the continental U.S. is and will be in a long-lasting heat wave which will be delivering day after day of 100 F days to cities in Texas and other southwest states with the heat dome moving north a few states before moving to the east coast where it will be creating some of the highest temps on record. He is basing this on solar flare activity which is blasting out a high level of positively charged ions. We will soon be seeing the effects it may have on the crops. Might those effects be like in 2012, 1988 or 1993 when we went through weeks of 90+ degree temps when rainfall was scant. Three important factors affecting the crop response will be nighttime low temps, humidity levels and amount of dew every evening and whether there is much wind. People and farmers who went through the blast furnace type conditions during the first week of August in 1988 with mid 90s temps, strong south winds and low humidities saw how quickly the corn got fried.
The condition of the corn crop improved drastically with the scattered storms which have passed through the Midwest in the last two to three weeks. Many areas in eastern Iowa, the northern half of Illinois and a good portion of Missouri were on course to suffer major yield losses with the corn crop if conditions stayed dry. They finally received the much-needed precipitation and the corn plants recovered to a great degree. Will there be enough water in the ground, enough dew every evening or enough scattered showers to allow the corn and bean crop to make it through the next 14 days of projected heat? We shall see. Of course, if the hot temps persist until Aug 2nd in Iowa and on the east coast until Aug 7th or 8th it will be front page news with lots of advice given for those who get to stay indoors during the hottest parts of the days.
Saying Goodbye
A very notable dairy veterinarian from Wisconsin, Paul Dettloff, passed away about two weeks ago after a stroke. He was somewhat a bear of a man, which was needed when working with much larger cattle. A sizeable percent of dairy farmers in the upper Midwest knew him, had attended one of his legendary cow colleges, read his books or received the advice he gave out freely, or drank the milk from A2A2 cows from Organic Valley where he served as the main DMV for that company for twenty years. He was a very friendly person and served as a pillar of Arcadia, Wisc. He was the go-to guy when stray voltage became an issue when utility companies or wind generators were improperly grounded, causing problems with two or four legged mammals.
A number of us got to know him as he was a member of our human health centered think tank. Paul always served as one of the keepers of the secret knowledge. I visited his basement museum and could not believe all of the reference books he had on the shelves, with many of them marked up where he had seen a valuable tidbit of value on the pages. His collections in maybe 100 different categories from arrow heads to microscopes were unbelievable. We found out at his celebration of life event was that he was of 25% Indian heritage. RIP Paul. It was the first funeral I attended where the guest of honor had a bushel basket of Salted Nut Roll candy bars on the table for the attendees to eat as that was his favorite candy bar.
His biochemist daughter took over the running and management of Dr. Paul’s Lab, where he researched and produced tinctures and other organic remedies for animal and human ailments will remain alive. We keep a few of his products around all the time as they really work One is called Dull-It. It is a topically applied natural anesthetic to relive all sorts of pain. Example uses include eliminating the pain when a blackened, injured fingernail detaches and falls off. Or is used after surgery to replace habit-forming opioid pain products. In recent years Meghan increased her knowledge along with nine other holistic practitioners who accepted a red-carpet invitation to visit China and received a two-week course in ancient Chinese herbal medicine.
The Corn Crop
The above normal heat caused a high percent of the plants to be tasseled and silked by July 10th, putting it a few days ahead of normal. Luckily many parts of the state received rain and had several consecutive days of below normal temps. That meant that pollen shed coincided with the silk emergence resulting in good pollination of every kernel site. The earlier stress conditions likely did influence the kernel count and eventually, yield potential. While imperfect pollination can cause yield loss, more kernels are lost in the first two weeks after fertilization by less than ideal growing environmental conditions and tip kernels aborting. Reduced ear length or reduced kernel depth are the result of poor moisture conditions during August.
One benefit of conditions remaining dry is that leaf diseases will remain low in incidence as fungal spores normally require a moisture film to be on the leaf to germinate and grow. Whether or not the spores and their infection peg are able to penetrate the cuticle to gain entry into the interior of the plant is influenced by the manganese level. High levels tend to not let this happen. Thus, the incidence of leaf disease in much of the Midwest has been low so far. In areas that has receive rain and more hours of dews are becoming common, expect more leaf disease to appear. If they do show up the best course of action would be to take tissue test or do sap analyses to detect any mineral deficiencies and get the levels up to or above the critical point.
The $64,000 question now is if and when is Tar Spot going to appear. More states and counties where confirmed cases of TS have been found and are being added to the list each week. Our opinion on Tar Spot is that it is not a pathogen caused disease, it is a mineral deficiency problem which causes the Phyllacora fungus to spit out manganese oxide onto the leaf surface when it does not have enough Zn, Cu and S to form the lactase enzyme to process the Mn as it comes into the plant. Normally Mn can be present in six varying forms. This runs contrary to all other opinions, but was partly formed by the former top Plant Path professor and head of the Threats Pathogen Committee. One factoid about TS spot is that it is the only fungal disease where you can’t wipe the lesion off the leaf surface. Doesn’t that sound more like welding splatter?
Now if a mineral deficiency is the cause, remember that moly is short in 95% of our corn and bean fields, boron is 90% short, manganese is short in 85% of the fields and zinc in 75% of the fields. What will increase these deficiencies would be the application of chelating herbicides or a killing of the beneficial microbes in the soil. Resorting to applying Cl or Fl materials multiple times is not long term sustainable. This fact is coming from the head biochemist at a small University called MIT. So, if you are a soil health believer it is time to make decisions with these parameters in mind. One last thing to consider is what other microbe and the disease it causes is known to plug a corn stalk’s plumbing system?
One thing about TS is we will get to see which opinions are correct and which ones were successful and gave the highest ROI while not harming the soil. This should become clear by mid to late September.
Rootworm feeding has now reached a high level in quite a few second tear corn fields plus a few first-year fields. What might be the causes? In first-year fields the attraction by pollen shedding waterhemp in 2022 fields offered a rich diet of pollen is the likely cause of heavy egg laying in 2022 SB fields. In second-year corn there can be factors such as incredibly dry soils kept planting time insecticides from spreading thru the root zone or the lack of sufficient nitrogen needed to form the delta endotoxin protein. Remember that insects don’t read the book.
Soybean Notes
Once the rows close on 20” and 30” rows, and dews that last until noon become common, the incidence of leaf diseases increases. Being able to detect and identify each of them will be critical to making the correct decisions about responses and possible fungicide decisions. Then you can make your calculations which will depend on product cost, expected financial reward, the mode of action of any herbicides and best method of application. The usual time frame for row closure in 30” rows is July 20th to 25”.
The one disease that appears in a high % of bean field as the rows close is Septoria brown spot. Its symptoms are yellowing leaves in the lower canopy with those leaves yellowing, the formation of brown spots on the leaves and those leaves falling on the ground. Its net effects are lower yields from the smaller seed size.
In northern locales White Mold can infect the plants thru abscising flower petals and they detach. Low lying fields, those bordering creeks or rivers, fields with limited air movement such as low spots, fields surrounded by trees or around buildings tend to be more affected, especially if the fields have a history of WM problems. The spores are produced from fungal fruiting bodies which look like small birds nest complete with eggs. Those bodies come from the small mouse-dropping like spore packets which can stay viable for up to eight years.
Various other leaf diseases such as Frog Eye, Cercospora, Downey Mildew can become problems can become problems in normal to wet years. Dry years can bring on more Anthracnose, Brown Stem Rot or Charcoal Rot. Each have their own symptomology. Carrying a 10x to 24 x hand lens is a wise choice to bring along on a field inspection.
Currently the fields where the managers who applied the cytokinin products or microbial products meant to add extra main stem branches look very good. As the plants move thru the V3 stage applying a foliar mineral mix can prove valuable as both dry soils or vascular bundle size may be too small to allow enough minerals to enter and move up to the pods to fill the seeds. More growers are searching for answers to help develop the skills needed to enter the category of expert high yield soybean grower. The knowledge and skills needed by high SB grower wanna-be’s are available to each person if they wish to develop such acumen. Such skills can be valuable as soybean prices remain unseasonable high.
Bob Streit is an independent crop consultant and columnist for Farm News. He can be reached at (515) 709-0143 or www.CentralIowaAg.com.