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Crop watch

By Staff | Aug 19, 2020

Typically mid through late July is the time for the county fairs, with their livestock exhibits and grandstand entertainment, leading up the State Fair and finally the Clay Country extravaganza. But not this year. Already the county fairs, State Fair and Farm Progress Show have all been ‘postponed into 2021. We have to hope that society will have calmed down by then and life, school and baseball are back to normal. Those have all been events we have been able to participate in and enjoy in the past. There have been a few livestock expos to substitute for them, but it’s just not the same.

As we enter the last week of July things could go either way as to yields. Most measurable rains seem to have been diverted away from western Iowa with I-35 seem to be the dividing line. Right now the Ames area has received about 7 inches of precipitation during the growing season while Waterloo has measured nearly 15 inches. There are chances for western Iowa to get a few showers this week, but so far this summer most of the fronts have dried out as they moved over eastern Nebraska. In my check of the U.S. Drought monitor 73% of the High Plains states are in the extremely dry to moderate drought category. This includes Nebraska, Kansas, South Dakota and Oklahoma. The Midwest region, which includes Iowa, Minnesota, Missouri, Wisconsin and Illinois has 34% of their territory in the abnormally dry to moderate drought category. The percentage of the territories in coverage and severity of drought conditions increased dramatically in the past week. This is exactly while the corn has been pollinating and kernels are early in their formation stages.

Strong winds and the aftermath

When some of those rains did arrive this past week they came very strong, that clocking up to and over 60 MPH. The first feeling the corn growers felt when they saw many of their corn fields holding flattened corn was a sick feeling of apprehension as plants that had been 6 to 8 feet tall were now one to three feet. A high percent of those fields looked much improved within 2 3 days as most of those fields grew brace roots that righted the plants and appeared to be none the worse for the experience. Questions arose as to why so many acres were affected. A knowledgeable crops person could point to potential causes:

1: Genetic families differ in root size, shape, depth of soil penetration, and ability to regrow to form new roots.

2: With flat sweeps on most field cultivators smear layers can be formed down 3 to 4″ that restrict root penetration.

3: The corn plants added about 48″ of growth in about ten days. Normally rooting depth matches top growth. This year when the soils warmed up the plants focus was on adding plant height and new leaf tissue and often did not have excess energy and sugars available for root growth. Typically when root lodging occurs there is heavy CRW feedings. That wasn’t the case this year.

The question from growers was “will the plants stand up”, “will the plants it be healthy thru fall”, and “might the yield be affected”. The answers to all of those typically started with ‘it depends’. For many Nebraska farmers the issues were with hail and greensnap. For those unfortunate growers the answer to greensnap is that final yields are typically trimmed by the same percentage that the stalks were snapped at. Research done in that state showed the yield reduction comes from the diversion of plant energy away from silking and pollination to forming new root tissue. They give a yield reduction estimate based on stage of growth of the corn plants. Corn blown over at V10 to 12 typically show a 2 -6% loss; V13 to 15 plants show a 5 to 15% reduction, and at V17 and later the loss was projected to be 12 to 31%.

Corn that got flattened just before tasseling that does not return to upright can get hit with a 50% yield loss it the rest of the summer is hot with high humidity. That happened back in 1985 east of Carroll. The horizontal plants get cooked. If the temps thru the rest of July and August are moderate or cooler and rainfall is moderate the yields can be close to normal. That was the case west of Marshalltown about two decades ago.

Excessive temperatures

So far June and July have been excessively hot. Fields in the southwest quarter and west central part of the state have seen their corn leaves roll for the last three weeks and often take on the ghastly gray green color. What will be occurring in such fields? Elwynn Taylor uses a figure called accumulated stress days. The optimum temperature for growing corn is typically believed to be 86 F. There can be a GDU gain when temps exceed 86 F and up to 92 F if that plant has sufficient moisture. When the plant is short of moisture and temps exceed 86 it is considered under stress, which reduces yields. In Dr. Taylor’s and Louie Thompson’s long term observations and calculations when stress days exceed 140 for the season the corn yields will be X bushels less than trend line. The current Iowa Mesonet figures as of 7/20 show a few locations are already close to 140. For example Clay County is already at 153. Carroll County is at 131. Cass County is at 148. Story County is at 98. Much of extreme southwest Iowa is 112 to 147. If the temperature predictions for the next few weeks proved correct and are in the low to mid 90s the cumulative totals could greatly exceed 140 by a wide margin.

The question then is ‘what will be the effect on yield’? The calculations aren’t clear to this rookie meteorologist, but the guidance given by Louie Thompson was that if the July temps average 4 F above normal, corn yields could be diminished by 600 K/ha. That is verbatim from the Agronomy 541 lesson. That translates in our measurements to a yield decrease of 9.5 Bu/A. Does that mean that July temps ran 8 degrees above normal the yields would be reduced 19 Bu/A? How about having a SDD above 200 by the time August is over with? We are going to examine Dr. Thompson’s old papers.

The common assumptions are that we cannot do anything about the temperatures and weather extremes. That was in the past. There are now several things that can be managed to help crops survive drought and heat. Improving soil health and increasing microbial life will improve rainfall infiltration, lower soil temps, and will allow soil biology to serve as a moisture reserve. The use of cover crops can play a large role in both. Keeping mineral levels high allows corn tolerate drier conditions. Fertilization with silica can increase moisture use efficiency by 33% by building a more intact vascular system.

Two new items to add to the above list from the last two years would be a seed treatment or foliar application of BioEnsure (Protect + or Heat Shield) that allows plants to tolerate temps up to 160 F. There is also a new product called Respite from BioDyne Midwest that when applied foliarly will lower the canopy temps by 8 to 9 degrees for two to three weeks per application. Thermographic imaging done in NCGA winning contest fields showed the product slowed ethylene formation and told the plants to keep forming sugars. That product is still available and can be applied for about $3/A. Dr. Isolde Haun Hahn, head of fungicide physiology research with Bayer, was gracious enough to give me her morning time when I was at their headquarters and open her books showing me the value of ethylene inhibition properties of the strobe fungicides. Keeping the plant canopy cooler is important.

Insect and disease issues

Currently the damaging insect populations are remaining low for all insects except Japanese Beetles. My best results in terminating them two weekends ago were with a combination of Mustang and Steward. Hero has been effective for me in the past. Be sure to lower the water pH to 5.5 and add oil to penetrate the chitin shell. We have also heard that a combination of O2YS (a chitinase elicitor compound) and Beauveria bassiana foliarly worked very well against this insect. Make a point to apply the BB to grassy areas as an inoculant as their eggs are laid there and their larvae feed on grass roots in the spring.

Aphids are appearing in soybeans in northern Iowa but at almost invisible levels. Unless they explode in numbers in South Dakota or Minnesota in the next few weeks it would be difficult to justify making a preventative application at R3. Maintain high Mo and Mn levels in your bean plants.

Leaf disease incidence remain at low levels in western Iowa but will increase in wetter areas to the east. In recent weeks I am seeing the first GLS and common rust at very low levels. Physoderma stalk lesions have become common with infected plants seeming to be very brittle at the lower internodes.

In soybeans the pathogens which can be found are early Septoria, which is the norm as rows close, a bit of bacterial spotting, and Cercospora. The evaluation and decision to apply a fungicide to beans should take maturity of your varieties into account. Fuller season varieties typically benefit the most from a strobe or strobe mix application. Remember that strobes alone are not controlling Cercospora any longer. Strobe and Triazoles don’t move systemically as do the carboxamides. Thus coverage and gallonage are important to their successful use.

The field observations on the Impulse treated fields are impressive. Having a nearly full spectrum of minerals applied in a fully systemic mix has definite benefits. Even in those fields one or more applications through R4 and R5 of a targeted mineral mix will plump bean size by 20 to 40% to offer high ROI benefits. I was in Kip’s field that yielded 154 Bu/a and used a very precise lab scale to measure his bean size: approx 1915 per lb. I still have some of his plants stored in an acrylic cylinder for viewing.

My quiz of the week. What is an Ibex? It can be a type of goat. It can also be a growing system developed by an inquisitive and innovative specialty crop grower from Fort Wayne, Indiana that the BioDyne Company is partnering with. It offers great ease in producing several food crops grown in very profitable ‘pick your own’ operations where healthy, locally grown food is in demand.

Lyme Disease Summit

Microbe Formulas was instrumental in developing the Farmer’s Shield product bundle to detox glyphosate and other toxins from the body. You may have seen Dr. Allan Lindsley and Ryan Riley speak at our conference earlier this year.

Microbe Formals is putting on a free on-line Lyme Disease Summit from July 27 – August 2. Over 36 specialists will be talking about Lyme Disease and how it affects the body. Difficult to diagnose and treat, Lyme disease has over 150 different possible symptoms: fatigue, mood problems, insomnia, neurological impairments, brain fog, migraines, gut issues, neuropathy, joint pain and others. If not properly treated, over time Lyme disease becomes chronic and can manifest in autoimmunity or a number of other degenerative, debilitating health issues. Sign up for the summit by going to chroniclymediseasesummit4.com/.

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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Crop watch

By Staff | Aug 19, 2020

For one to two months now we have peered into the western sky or onto a radar map to see when our next major rains would arrive. For a high percentage of the people involved in farming, other profession or activity directly dependent on mother nature to deliver our needed rainfall we have been left wondering why the large front or storm cluster detoured to the north or south, or only left a few lightning strikes instead of a meaningful amount of moisture in the gauges. Close does not count when our crops are thirsty. It has to be measurable and end up in the rain gauge. We have had a bit of a reprieve with the temps cooling down into the 70s for a few days. That lowers the evapotranspiration rate lettings the crops hang on for a few more days. The words of wisdom provided years ago by an old Oklahoma farmer is that ‘it always rains at the end of a dry spell’.

So are our crops and their expected yields going to be affected? Anyone who has walked into the fields and looked at the still flat pods or pulled the husks down on a few ears knows the answer to that question. Why haven’t the markets or traders in Chicago reacted in a positive fashion? Part of that may be that so many crop conditions are based on computer projections and modeling. A high percentage of the states still have their two major crops rated in the 75 + % good to excellent categories. In reality those who network across the major crop growing midsection of the country know that the area deemed extraordinarily dry thru moderate or extreme drought runs from Pennsylvania to the SW part of Colorado. There are parts of the southern Midwest as in Missouri and Arkansas and in the northern tier of states such as the Dakotas, Minnesota and Wisconsin that have been supplied regularly with good rains all season.

Eventually the rains will resume falling. Will the corn and bean plants still be alive and where the kernels and seeds will be able to increase their size? Will the rains come in amounts to hinder the harvest, what there will be of it? It’s too bad that Mother Nature could not save some of the excess rains from 2018 and 2019 and deliver them now when they would be appreciated.

Corn and bean crop observations

For a few weeks being inside hot and sweaty corn fields was uncomfortable. Because plants are not mobile climatologists wanted a means to measure the cumulative stress the plants had to endure. Dr. Louie Thompson of ISU developed his Stress Degree Measuring System where they recorded the daily temperatures exceeding 86 F. He and Dr. Taylor recognized there needs to be a moisture deficit component to it, since corn tolerates temps up to 92 F if they have enough moisture, but uneven rainfall made the site specific calculations more difficult. Once the cumulative totals exceeded 140 the temps could become a negative and start subtracting from yield. I mentioned in my previous column that several sites in Iowa had already exceeded the 140 by July 20th, with the regional tallies varying across the state. The damage resulting from excessive heat can now be seen as bubble kernels, open kernels sites, aborted tip kernels and plants that are wilting severely from a moisture shortage in the root zone. Many ears across from the entire Midwest have lost 2- to 3-inches of tip kernels with most shallower than normal. My field observations this week in Story and Boone counties detected many ears that are 60 to 80% dented already. That figure can result as being positive or a negative in that those plants having the majority of their grain filling completed before the moisture runs out completed that task. It also means that when we start receiving adequate rain the fully dented of black layered plants can’t reverse course and return to the task of starch accumulation. North of Hwy 3 the plants are not as advanced in maturity and could still capitalize on late rains.

As is typical most articles and field interviews about the crop focused on the pollination and fertilization events as though they were the sole criteria of bounteous yields. I am more concerned about the degree of stress endured by the plants in the 10 to 14 days following fertilization that can lead to kernels abortion. Knowing that our stress day accumulation was high during those days and seeing the resulting shallow kernels and multiple inches of tip back, it suggests the NASS good to excellent ratings of both crops have to be questioned. Once a person gets beyond the end rows in most corn fields conditions change. For any crop modeling company to pronounce a statewide Iowa corn yield average of 201, Nebraska at 183 and Kansas at 131, they can be accused of counting their chickens way too early. Losing 1/3 to 1/4 of the tip kernels coupled with kernels only half of normal depth projects to how many bushels?

In areas not receiving rain in the past month the beans range from having a very good yield potential with lots of unfilled pods and with three or more side branches to only 12 to 13 podded nodes with few branches. Early planting led to forming more podded nodes. The extra side branches can form if cytokine hormone levels are high in the plants, mineral and amino acid levels are high, or if plant selection by the SB breeders used branching ability as a selection criteria. Another plant trait seen in certain genetic lines in the past 3 or 4 years has been the formation of flower racemes at the nodes. This is typically a characteristic seen in determinant varieties in South America.

As of Aug 6th very little pod fill has occurred. It is critical that rain begins falling, or we will see the formation of ethylene, the stress hormone, will reach a high enough level to cause abscission layers to form and the pods fall off.

A mystery or a deception?

After hearing how the CCP withheld information from the rest of the world on this virus, having Chinese seeds show up in mailboxes in many states, we have to be a bit suspicious of such boxes. It likely was not a Publisher’s Clearance House gimmick. They had to be scanned at the site of origin by one of the PO electronic sorters. Are we being played on this?

Disease situations in the Midwest

The incidence and severity of foliar diseases on the corn and bean plants typically depend on: the hours of plant wetness or dews, mineral levels within the plant with regard to deficiencies of Mn, Cu, Bo and Zn; the presence of inoculum either floating in from infected fields upwind or from intact residue from an earlier infected crop and; genetic susceptibility of the hybrid to the disease; maturity stage of the crop. Drier parts of the Midwest until recently had very few leaf disease appearing in their corn or bean fields. Now after pollination the immune response in corn is lowered as energy is devoted more to grain fill. The conditions also change in soybean fields as with canopy closure come higher humidity levels and more hours of leaf wetness. Thus with rainfall being more plentiful in Eastern Iowa there has been greater disease pressure.

There are now several diseases now appearing in corn, again more so where tissue tests indicated mineral shortages. The list includes light GLS, a bit of NCLB, Physoderma on the leaves and stalks, Eyespot, Common and Southern Rust, and what may be very small Anthracnose spots which may coalesce as time advances. One also has to acknowledge that as the soils have gotten progressively drier two things happen, the minerals in the soil are less available to the plants due to both soil hydraulics and less biological activity plus less water is available to be pulled into the plant via osmotic pull. This is when if you want to get minerals into the plant the best method would be with Y-drops or foliar application.

In bean fields where the canopies have closed the incidence of dews will increase and we will see more Septoria, Downey Mildew, the two forms of Cercospora, and possibly a few others. The challenge of optimum response to fungicide dollars depends on application timing, penetration of the spray, and residual length of the product(s). It would be helpful to know exactly how long each product can last, but getting exact information is difficult and costly as analytical costs are high. Until now there have not been many systemic product available for use in row crops. The more recently introduce products have such movement in the plant.

Dicamba damage

It is still readily apparent as to which bean fields, specialty crops or trees suffered from Dicamba drift. The recovery of each bean fields depended on dosage and number of times it got dosed. Recovery percentage varied from good recovery and decent growth to still seeing a large reduction in growth.

Part of the information weighed by the judges on the Dicamba ruling was input from DNR staff who had noted considerable damage done to older trees including oaks and maples. Speaking from observations the burr oaks are highly susceptible with the stunted leaves resembling the distorted growth that a Ni deficiency in pecan tree causes (squirrel’s ear). Hackberry as well as other tree species are also casualties. We have found that applications of several minerals can stimulate new growth. Those we have tried include copper, manganese, and zinc. Having the minerals chelated by amino acids is key due to their systemic movement. The new products from PhytoBiotics have worked very well and we are continuing the testing. The burr oaks sprayed on July 1 formed about 15-inches of new growth by Aug 3.

I have never had a variegated maple tree, but this year we have several with the leaves looking exactly like bad IDC (iron chlorosis). We are hoping they recover with the mineral application. Pine trees have to be included in the discussion as many windbreaks include those trees on a serious decline. So it appears that rural and town dwellers now have an affordable remedy to treat the trees on their properties.

Insect threats

So far the most damaging insect seen in 2020 have been the Japanese beetles. They seem to devour exactly the crops you don’t want them to, cherries, berries, corn silks etc. The best remedy for 2021 will be to spray the fungal spore product known as Bb2.5, or Beauveria bassiana, on grassy areas which will then be populated with the fungus that will consume the root feeding larvae. So far the soybean and corn aphid counts remain low. In bad, treatable years the populations had reached treatable populations by July 25th. Spider mites are being found at low levels in both corn and bean fields. These populations can explode as the normal beneficial fungus levels drop and the mite reproductive rate increases with hot and dry weather.

Damage done by treatable sucking insect populations reached the highest percentage in dry years when the plant sap amounts used to fill the seed were the most limited. A few areas in western Iowa have been found to have detectable populations of soybean gall midge. Without better detection devices or procedures, which may come from research being done by Justin McMehan, from UNL, with collaboration by Erin Hodgson at Iowa State, we are somewhat in the dark on understanding their biology and potential treatments of them. We have heard of good results where a mix of Bb and Chitosan products was applied to insects using in-season foliar applications on specialty crops in Minnesota and Wisconsin.

On another fruit growing note. My ready-to-pick peach trees were attracting lots of Japanese Beetles. I sprayed them with O2YS, a safe chitosan product that has an organic version and they left and have stayed away. This product causes the trees to produce an enzyme that will dissolve insect parts.

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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