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Agronomic Crops Network

Ohio State University Extension


C.O.R.N. Newsletter: 2016-26

  1. Ear development impacted by drought conditions

    Author(s): Peter Thomison

    Drought and heat adversely affected ear and kernel formation in many Ohio corn fields this year. Poor ear and kernel development is associated with variability in plant growth within fields that is related to differences in soil moisture.   In some areas within fields subject to protracted dry conditions, ears are absent (“barren”) or severely reduced in size with a few scattered kernels (nubbin ears). Where the impact of drought was less pronounced and plant height and color look normal or near normal, ear cob size may be normal but kernel number is markedly reduced. No kernels may be evident on the last two or more inches of the ear tip. Several factors may cause this problem. The ovules at the tip of the ear are the last to be pollinated, and under the stress conditions only a limited amount of pollen was available to germinate late emerging silks. Pollen shed was complete or nearly complete before the silks associated with the tip ovules emerge. As a result, no kernels formed at the ear tip. Uneven soil conditions and plant development within fields may have magnified this problem. Pollen feeding and silk clipping by corn rootworm beetles and Japanese beetles can also contribute to pollination problems resulting in poorly filled tips and ears.

    Incomplete ear fill problems resulting from drought stress may also be related to kernel abortion. If plant nutrients (sugars and proteins) are limited during the early stages of kernel development, then kernels at the tip of the ear may abort. Kernels at the tip of the ear are the last to be pollinated and cannot compete as effectively for nutrients as kernels formed earlier. Some agronomists and farmers characterize the kernel abortion that occurs at the end of the ear as “tip dieback”, “tip-back”, or “nosing back”, although poor pollination is also usually a factor affecting poor kernel set at the tip. Kernel abortion may be distinguished from poor pollination of tip kernels by color. Aborted kernels and ovules not fertilized will both appear dried up and shrunken; however aborted kernels often have a slight yellowish color.

    Zipper ears are another ear development problem evident in drought affected fields. Zipper ears exhibit missing kernel rows (often on the side of the cob away from the stalk that give sort of a zippering look on the ears”).  The zippering is due to kernels that are poorly developed and/or ovules that have aborted and/or not pollinated. Zippering often extends most of the cob’s length and is often associated with a curvature of the cob, to such an extent that zipper ears are also referred to as "banana ears". For more information and pictures of these ear development problems and others ear abnormalities, check the following: “Troubleshooting Abnormal Corn Ears” available online at

  2. Late season purple corn

    Growers are reporting reddish-purple plants in their corn fields and sometimes observing that the degree of purpling varies among hybrids. Several factors can cause purpling of corn plant tissues late in the season. As a defense mechanism to protect photosynthesis, a corn will form pigments to help absorb excess light and divert it away from their photosynthetic centers as a form of sunblock. This purple color is from anthocyanins, which can be formed from excess light or from a buildup of sugar (sucrose). In some cases, like in cool bright conditions early in the season, anthocyanins are important because they help the plant tolerate the bright sunlight and get rid of the extra energy it can’t use for photosynthesis. Diverting the excess sunlight protects the photosynthetic mechanism and can reduce the time needed for the plant to recover from excess light stress. In the cases of purpling during grain fill, the pigmentation is likely to occur when plants cannot utilize all the sugars that the plant is producing. Excess sucrose produced by photosynthesis accumulates in the leaf tissue, husk tissue, parts of the stalk, and triggers formation of the reddish-purple pigment anthocyanin. This can occur in some cases because the silk strength is less than what would normally be expected (barren plants and plants with ears removed prematurely, wildlife damage (especially raccoons), etc.). In years with environmental stress - like the drought this year, plants may have smaller than expected ears or few kernels per ear which can result in prominent purple plants. Disruption of the sugar distribution channels by pests like corn borers can occur when they burrow in stalks and ear shanks. This damage results in a buildup of sugars in the leaves and stalks triggering anthocyanin production and the appearance of purple plants. Purpling is also associated with plants producing "beer can” ears. In this case, these stunted ears with limited numbers of kernels cannot use all the sugars being produced by the plants, so sugars accumulate and plants turn purple. Traces of purpling on plants, which appear healthy, with normal ears, also occur. The extent to which plants turn purple is also influenced by hybrid genetics with some hybrids more inclined to purple than others when some stress disrupts the flow of sugar from leaves and stalks during grain fill.

  3. Late season diseases are making their appearance

    Author(s): Anne Dorrance

    Sudden death syndrome.  I was scouting the sudden death syndrome study and symptoms have started.  And due to the calls I am getting it is also in some producer’s fields.  Sudden death syndrome (SDS) is a fungal disease of soybean and is limited to a few locations in Ohio.  Interestingly, these fields where SDS occurs in Ohio, also have high SCN populations.  These two culprits often appear together.  The fungus is now called Fusarium virguliforme and colonizes the tap root and roots so they turn dark in color.  After the rains last week, it may be possible to observe the signs of the pathogen on the tap roots, with the formation of pale blue to blue green conidia.  This fungus produces a toxin which is why the leaves have the irregular shaped yellow spots forming between the veins which turn necrotic and eventually cause early defoliation of the plants.  The internal tissue of the stem, the pith is white – compared to brown stem rot which is brown.  In SDS, the toxin moves up the plant not the fungus; whereas in Brown stem rot the fungus is actually colonizing and degrading the plant tissue. Severity of infection, timing of disease onset, SCN population numbers all contribute to the amount of yield loss that will occur.  

    White mold or Sclerotinia stem rot.  First plants dying from Sclerotinia stem rot were reported last week.  Even with the dry weather during flowering, infection did occur.  As you recall we had many cool nights in early July and heavy dews, so my hunch is that contributed to the favorable environments.  Sclerotinia is another fungal pathogen that infects the old and dying flowers.  This fungus secretes an acid which degrades the tissue, sometimes appears water soaked on the stems and then the fungus just takes off, becomes very white and fluffy on the stems.  It will then form hard black – irregular shaped sclerotia which serve as the survival structures and can be easily moved around the farm on equipment.

    Diaporthe Stem canker.  This is one that we have not observed in Ohio very often.  Again this is a truck stopper as you drive by fields and see that the tops are dying back too early.  This fungus also infects plants at the third or fourth node and basically girdles the plants.  Infections occurred when the plants were in the early vegetative stages and has been “hanging out” waiting for the plant to move into the final growth stages.  The key difference between this and Phytophthora is that the plant will be green, no internal infection in the lower 3 nodes = whereas with Phytophthora stem rot on highly susceptible varieties, the plant is colonized from the base of the plant up the stem.

    Phytophthora stem rot.  I can’t leave this one out as there are some soybean varieties that do not have the full resistance package we need for Ohio fields.  After the rains over last weekend and off and on last week, stem rot is showing up in the field that were saturated.  Plants will turn yellow and wilt, leaves will cling to the plants as it is dying.  Again, on susceptible varieties, the chocolate brown canker will be moving up the stem.

    Variety selection is key to managing all of these late season diseases.  Begin to scout your fields, if you find one of these – make note of that variety and make sure to make a change.  Do not plant the same variety in the same field as you now know that you have inoculum in that field.  For Sclerotinia in particular, what amounts to a few scattered plants this year, can amount to a lot more down the road.  In all of field studies, where there is a resistant variety planted we are not observing the disease. Click here to see a summary PDF of late season soybean diseases.

  4. Prevention is the key to managing stored grain pests

    The primary causes of grain spoilage during storage are excess moisture and high temperature. However, insects can infest any grain that is not handled properly or that is stored longer than 6 months. Damage from weevils or other stored grain insects can be costly. Unfortunately, they often are discovered when grain is being taken out of the bin. At that point, the damage has been done and there are few control options.

    The elements of pest prevention, the key to successful long-term storage are sanitation, protection, and inspection. Arguably, sanitation is the key because infestations of stored grain insects rarely begin in the field. They usually develop from small numbers of pests present in or around farm storage bins or in grain handling equipment. An effective sanitation program can greatly reduce the chance of having serious problems with these insects.

    Harvesting should begin with empty, clean bins. Never put newly harvested grain into bins containing old grain. Remove any residual grain as thoroughly as possible using shovels, brooms and an industrial vacuum. Clear dust, webbing and fines from around any cracks and crevices, doors, seams, and vents. Inspect clean bins and repair any cracks or holes that could allow moisture or insects to enter. Then, spray the inside of the clean, empty bins completely with a labeled residual insecticide. Apply a coarse spray to run-off at least 2 weeks before binning. Pay close attention to areas that might hide insects, such as under perforated floors and vents. Cracks around doors and vents may serve as entryways.

    Thorough preparation also should include the area immediately around the bins. Remove and destroy any spilled grain. Clip tall weeds and grasses that can harbor spilled grain, insects, and rodent pests. Inspect outside walls, especially the base and roof for damage that could allow pests and moisture to enter.

    Put only clean, dry grain into the bins. Most stored grain insects require 13% to 15% moisture for maximum feeding and reproduction. Clean grain that is likely to be held for more than 6 months. This reduces the chances for problems with pests like bran beetles that live on fines and produce metabolic heat and moisture that reduces the stored grain's quality.

    Level the grain surface after the bin is full. Good airflow allows improved moisture and temperature control and easier access for inspection. Regular grain bin inspection provides important information on the general condition, temperature, and moisture. Early detection of an insect infestation allows quick response to deal effectively with it.

    See Controlling Insects in Stored Grain for more information.

    Thanks to guest writer, Lee Townsend, Extension Entomologist, University of Kentucky

  5. Bean Leaf Beetles Don’t Quit at the End of August (Unlike Your Summer Help)

    As we get into the R5-R6 growth stage of soybean, now is the time to look out for pod and seed feeding insects, especially bean leaf beetles, grasshoppers, and stink bugs.  Last week’s article focused on stink bugs, which pierce the pod and suck out seed matter.  Bean leaf beetle and grasshopper chewing damage is more obvious.  Grasshopper damage is usually focused on field edges, but bean leaf beetles will be spread more evenly through the field.  We have not had any reports of unusual levels of pod feeding activity, but growers are still advised to monitor their fields for these two insects.  This concern is especially important with fields that stay green in September because of late planting, including organic, double-cropped, or intercropped soybeans.  These juicy green islands will be particularly attractive to second-generation bean leaf beetles stocking up for the winter, and they may move into green fields from other fields that are starting to yellow, resulting in unpleasant surprises for the unwary.

    Treatment to prevent pod damage from bean leaf beetle is based on the level of insect injury observed on the pods.  Select 10 plants at random and inspect all of the pods on each.  Count the total number of pods and the number of pods exhibiting pod scar injury, and use this to determine the percent of pod injury.  It is important to estimate percent pod injury on inspection of the entire plant. Treatment is justified if the percent pod injury is approaching 10-15%, and bean leaf beetle adults are still present in the field.  When pods dry down the beetles will leave of their own accord.  The same general guidelines can be used for grasshopper damage, though keep in mind that this damage is often restricted to field edges and might not be a widespread problem in the field.

    At this time of year producers should also be mindful of the pre-harvest intervals (PHI) of any insecticides they use, many of which are as high as 45 days.  More information on bean leaf beetles can be found at:

  6. Farmer Led Water Quality Monitoring-Initial Results and Request for Participants

    Ohio State University Extension is seeking additional 60 fields in the Western Lake Erie Basin to help with a water monitoring research project looking at Dissolved Reactive Phosphorus (DRP) losses from fields.  Farmers already participating do not need to signup field already being monitored are encourage to add additional fields by visiting the signup link at  Increases in DRP in the watershed have been tied to increased occurrences of Harmful Algal Blooms in Lake Erie. The data collect will help better quantify actual losses from an economic and environmental standpoint, lead to tools that can target high risk fields so cost effective Best Management practices can be designed that maintain crop productivity while reducing phosphorus losses.

    This project gives a farmer the chance to find out how much Dissolved Reactive Phosphorus (DRP) in pounds per acre is leaving their field site, based on their crop production system. Farmers will be provided their individual data plus summary data for all sites in the project. The data will be used to understand what conditions lead to DRP loss and what recommend Best Management Practices (BMP’s) can be used to reduce nutrient loss.

    A plastic water sampling disk is placed at the end of field tile or within drainage water management structures by the farmer during two upcoming periodsr, October to December-2016 and March to June-2017. The sample devices are changed out every 4 weeks during each sample period. A standard soil test analysis will be provided as well. There is no cost to the farmer for the water or soil sampling.

    The primary field selection recommendation is that drainage water sampled should only include water from the farm practices being done by the cooperating farmer. Shared field mains that include multiple farmer managements, road drainage, household water drainage or other areas not under control of the farmer should not be used. The field main should drain 5 or more acres. There is no upper limit to field size as long as the drainage area is known and the field area drained is under the control of the cooperating farmer. The end of the field main tile or a drainage control structure on the main tile should be accessible for deploying samplers.

    Field Management information by date for tillage, fertilizer applications and crop cover planting that occur in the 3 months prior to sampling through when the last sampler is pulled out will be collected. This data is extremely valuable to understand how practices influence the water quality results.

    Preliminary data from Fall of 2015 sampling with 35 farmers participating on 45 fields representing 1600 acres the following results were attained for the period:


    Concentration Range

    Sample Period

    Days Deployed

    Total Mass DRP (ug)

    Concentration (ppm)









    None detected (ND)














    The spring 2016 sampling was just completed with an estimated 93 farmers participating who sampled 135 fields representing 4725 acres.

    More details on the sampling project as well as a signup link can be found at or contact Lee Richter, Program Coordinator, Water Monitoring Project, or Greg LaBarge Please signup by September 20th.


  7. Ohio No-Till Field Day - August 31

    Author(s): Mark Badertscher

    Are you thinking about switching to no-till and have some questions you need answered before taking the leap?  Maybe you‘ve been planting no-till soybeans for years and are thinking about adapting this practice to corn.  Adopting no-till requires understanding how it affects drainage, soil structure, organic matter, weed control, and the application of pesticides and chemical fertilizers, all of which influence both yields and environmental impacts.

    No-till is known for its ability to control erosion, conserve soil moisture, minimize fuel and labor costs, and build soil structure and health.  Done properly, no-till systems can meet or exceed conventional tilled crop yields while reducing fuel and equipment costs.  Farmers can see how no-till can work within their operation by attending the Ohio No-Till Summer Field Day, August 31 on the Jan Layman Farm, 15238 Township Road 119, Kenton.  Registration will begin at 8:00 am with no-till machinery and exhibitors followed by the program starting at 8:45 am.

    Several sessions at this August 31st field day will address the use of cover crops in no-till systems.  Equipment demonstrations include Aqua-Till, which uses ultra-high-pressure water jets to cut into the soil for planting, and a John Deere 2510H dry fertilizer injector.  On-site registration is $60 and includes lunch.  A complete agenda is available at  This event is being sponsored by the Ohio No-Till Council, the Ohio Soybean Council, the Ohio Corn Marketing Program, the Soil and Water Conservation Society, OSU Extension, OARDC, NRCS-USDA, the Hardin Soil and Water Conservation District, and Ohio’s Country Journal.

  8. Fertilizer Application Certification & Training (FACT), Nutrient Management Field Day - September 6th

    OSU Extension Crawford County will be hosting a nutrient management field day for fertilizer application certification on Sepember 6th from 1-4 pm. The program will be held at OSU Extension Unger Farm 1303 Bucyrus-Nevada Rd., Bucyrus, OH 44820. For more information visit or call 419-562-8731 to make a reservation. As a reminder all producers who apply fertilizer to 50 or more acres per year including side dress nutrients to corn will need to be certified by September, 2017. This field day will be a great way to get that taken care of before a busy winter.  

  9. Unlawful or Anti-Competitive Activities-The Big Data Confusion: Part 13

    Author(s): John Fulton,

    A common concern for growers when working with an Agricultural Technology Provider (ATP) is that their data may be used by that ATP to benefit itself in the marketplace.  According to the Federal Trade Commission, it is illegal for businesses to act together in ways that can limit competition, lead to higher prices, or hinder other businesses from entering the market. The 12th farm data principle outlined in the American Farm Bureau “Privacy and Security Principles for Farm Data” highlights Unlawful or Anti-Competitive Activities in which “ATPs should not use the data for unlawful or anti-competitive activities, such as a prohibition on the use of farm data by the ATP to speculate in commodity markets”.  The primary concern is that a company could use farm data (however it is access) to market various crops or influence input sales.

    Within the agreement or terms and conditions between a grower and their ATP(s), there should be an explicit statement regarding the prohibition of anti-competitive activities.  If the contract does not specifically mention these unlawful or anti-competitive activities, one should be on guard for wording that could disguise these type of actions.  For example, verbiage that mentions being exclusive to one particular ATP, discriminatory pricing practices that appear as pricing based on the amounts or quality of data being managed, and requirements that a grower must purchase additional services in order to use basic ones.  By being knowledgeable about what activities constitute unlawful or anti-competitive behavior, growers can be better prepared when entering into contract agreements with an ATP.

Crop Observation and Recommendation Network

C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.


Andy Michel (State Specialist, Entomology)
Eric Richer, CCA (Field Specialist, Farm Management)
Glen Arnold, CCA (Field Specialist, Manure Nutrient Management )
John Barker (Educator, Agriculture and Natural Resources)
Kelley Tilmon (State Specialist, Field Crop Entomology)
Lee Beers, CCA (Educator, Agriculture and Natural Resources)
Les Ober, CCA (Educator, Agriculture and Natural Resources)
Mark Badertscher (Educator, Agriculture and Natural Resources)
Mike Gastier, CCA (Educator, Agriculture and Natural Resources)
Peter Thomison (State Specialist, Corn Production)
Pierce Paul (State Specialist, Corn and Wheat Diseases)
Sam Custer (Educator, Agriculture and Natural Resources)
Sarah Noggle (Educator, Agriculture and Natural Resources)
Steve Culman (State Specialist, Soil Fertility)
Ted Wiseman (Educator, Agriculture and Natural Resources)


The information presented here, along with any trade names used, is supplied with the understanding that no discrimination is intended and no endorsement is made by Ohio State University Extension is implied. Although every attempt is made to produce information that is complete, timely, and accurate, the pesticide user bears responsibility of consulting the pesticide label and adhering to those directions.

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