C.O.R.N. Newsletter : 2020-03

  1. Wetter Conditions Remain Favored into Spring

    Author(s): Jim Noel

    The outlook for February calls for near normal temperatures after the warm start with normal to above normal rainfall. That was the only change in the outlook. February looks wetter than a few weeks ago. Rainfall the next two weeks will average 1-4 inches across the state. Normal for two weeks is about 1.5 inches. You can see the consensus 16-day rainfall outlook at:


    The spring outlook is for a chilly start but a warmer than normal finish. Above normal rainfall is in the outlook until at least May.  However, it does not look as wet as 2019 at this time.

    The trends in the climate models indicate a switch to hotter and drier weather as we go through summer.

    You can keep up-to-date on all the NOAA climate outlooks at:


  2. Overwintering of Pathogens and Insects - What do Winter Temperatures Tell Us About Next Season?

    Frogeye leaf spot

    Over the years we have developed databases of winter temperatures followed by scouting to indicate starting pathogen populations for Ohio.

    Frogeye leaf spot – We have documented early infections and overwintering ability of the fungus, Cercospora sojina, that causes frogeye leaf spot. It appears that when there are less than 10 days during the months of December, January and February of less than 17 F, we have had reports of outbreaks of frogeye leaf spot.  This occurred in fields where there was a high level of inoculum at the end of the season the same or similar moderately to highly susceptible cultivar was planted into the same field again which then initiated the epidemic that much sooner.  Losses of greater than 35% in yield or very early fungicide applications were necessary. 

    Expecting continued warmer winter temperatures, for fields with a history of frogeye leaf spot, and no-till production systems, the first thing for farmers is to do now to mitigate losses in 2020:

    1. Rotate fields with high levels of frogeye leaf spot into corn or another crop.
    2. If it is still targeted for soybean, look at their soybean varieties frogeye leaf spot resistance scores.  Your seed dealer will have more information.  Plan now for what fields they will go into.
    3. Scout the susceptible cultivars much earlier than what we have called for in the past and monitor levels.

    Another pathogen that may be more prevalent after a warm winter is Stewart’s bacterial wilt.  This disease is transmitted to corn by corn flea beetle which survives in greater numbers in warm winters. This is a greater problem in popcorn and sweet corn as most field corn has high levels of resistance to the bacterium.

    Most other field crop insect pests in Ohio are not highly influenced by winter conditions as they are well-adapted to withstand cold overwintering conditions.  Once exception is Mexican bean beetle, an occasional pest of soybean (especially in central Ohio).  Warm winter conditions may cause higher populations of this insect the following field season. 

  3. Tar Spot of Corn

    Tar Spot, a new disease of corn caused by the fungus Phyllachora maydis, was reported for the first time in Ohio at the end of the 2018 growing season. At that time, it was found mostly in counties close to the Indiana border, as the disease continued to spread from the middle of country where it was first confirmed in 2015. Over the last few weeks, there have been several new, confirmed report of Tar Spot in Ohio, this time not only in the northwestern corner of the state, but also from a few fields in central and south-central Ohio. As was the case last year, disease onset was late again this year, with the first reports coming in well after R4. However, some of the regions affected last year had more fields affected this year, with much higher levels of disease severity. It could be that Tar Spot is becoming established in some areas of the state due to the fungus overwintering in crop residue from one growing season to another. This is very consistent with the pattern observed in parts of Indiana and Illinois where the disease was first reported. We will continue to keep our eyes out for Tar Spot, as we learn more about it and develop management strategies. You can help by looking for Tar Spot as you walk fields this fall, and please send us samples.      Tar Spot

    What does it look like? Even though corn is drying down, if Tar Spot is present, you can still detect it on dry, senescent leaves almost as easily as you can on healthy leaves. So, please check your fields to see if this disease is present. “Symptoms of tar spot first appear as oval to irregular bleached to brown lesions on leaves in which raised, black spore-producing structures call stroma are formed... giving the symptomatic areas of the leaf a rough or bumpy feel to the touch… resembling pustules on leaves with rust. Lesions … may coalesce to cause large areas of blighted leaf tissue. Symptoms may also be present on leaf sheaths and husks.” As the name of the disease suggests, symptoms look like the splatter of “tar” on the leaves. In some cases, each black tar-like spot may be surrounded by a necrotic halo, forming what is referred to as “fish-eye” lesions.   

    What causes Tar Spot and how damaging is it? In the past, the greatest impact of this disease in terms of yield loss were observed when P. maydis-infected plants were co-infected with a second fungus called Monographella maydis. In other words, the damage tended to be much more severe when the two fungi worked together to affect the plant. So far, only the first fungus, P. maydis, has been reported in the US, but based on work done in Illinois, this pathology alone is capable of causing substantial yield reduction on highly susceptible hybrids when conditions are favorable and infections occur early.  

    Where did it come from and will it survive and become established? At this point it is still unclear as to how Tar Spot got to the US in the first place and how it continues to spread. The fungus is not known to be seed-borne or infect other plant species, so corn seeds and weeds are unlikely to be the sources of inoculum. However, the fungus can survive and be moved around on fresh and dry plant materials such as leaves and husks. In addition, since spores of the fungus can be carried be wind, it could be blowing in from neighboring states/counties/fields. Although not yet confirmed through survival studies, it appears that the fungus could be overwintering in infected crop stubble between growing seasons.

    What should I do if I find Tar Spot? If you see anything that fits the description of, or resembles (Picture) Tar Spot, please inform your state specialist, field specialist, or county extension educator, but most importantly, please send samples to my lab (1680 Madison Ave, Wooster, OH) for confirmation. We will also be using your samples to study the fungus in order to develop effective management strategies.

    Read more about Tar Spot of Corn at:




  4. Yield Survey Results Released

    Corn harvest

    2019 was a growing season that will stick in our memories for years to come. Figure 1 shows the accumulated precipitation compared to normal conditions across Ohio for April and May 2019. Near record spring rains across west central and northwest Ohio (seventh and third wettest on record respectively), fell on already saturated ground, contributing to unprecedented delays in planting progress. Figures 2 and 3 show the planting progress for both corn and soybean planting from 1979-2019. Planting for both crops was the slowest on record and we pushed the boundaries with planting dates extending later into the season. These conditions also led to a record 1,564,611 unplanted acres at the end of the season.










    The excessive rainfall during the 2019 season provided an opportunity to assess the impacts of extreme planting delays on yield in Ohio. Thanks to everyone who contributed data to the survey, we received data from 489 fields in 51 Ohio counties.

    Corn Results

    Reported planting dates reported ranged from 4/10 to 6/28 for corn fields, with an average planting date of 5/30. This average planting date is approximately 15 days later than USDA progress reports for 50% acres planted from 2015-2018. Table 1 shows the reported corn yield, moisture, and test weight by Ohio crop reporting district. Despite the challenging season, yields were higher than the 10-average yield reported by USDA NASS in all districts except the Central, and South Central districts. Figure 4 shows the relationship between planting date and yield. Yields trended lower as planting date was delayed.

    Average Corn Yields

    Corn Yield

    Soybean Results

    Planting dates reported ranged from 4/4 to 7/15 for soybean fields, with an average planting date of 6/11. This was off the 2015-2018 average 50% planted progress date reported by USDA by about 19 days. Table 2 shows the reported soybean yield, moisture, and test weight by Ohio crop reporting district. Despite the challenging season, yields were higher than the 10-average yield reported by USDA NASS in all districts except the West Central, Central, and Southeast districts. Figure 5 shows the relationship between planting date and yield. Yields trended lower as planting date was delayed.

    Table 2. Average reported soybean yields, moisture, and test weight by crop reporting districts. USDA NASS 10-year average county yields included for comparison. Values in red are averaged from data from fewer than ten fields.

    Average Soybean Yield

    Soybean Yield


    Overall, reported 2019 yields, where farmers were able to plant, were higher than expected for both corn and soybeans in Ohio. While good yields were achieved at some late planted locations, the risk of yield loss increased as planting was delayed for both crops.

  5. Are Sulfur Deficiencies Becoming More Common in Ohio?


    Sulfur is an essential macronutrient for crop production, often ranked behind only nitrogen, phosphorus, and potassium in importance. Overall, for corn and soybean, deficiencies are fairly rare. However, deficiencies can occur and are most likely on sandy soils with low organic matter (<1.0%). Much like nitrogen, the primary form of sulfur in the soil is found in the organic fraction, and the form taken up by plants (sulfate) is highly mobile. For every 1 percent of organic matter, there is approximately 140 pounds of sulfur, most of which is unavailable. Like nitrogen, sulfur must be mineralized to become plant available. (Plants may exhibit sulfur deficiencies under cool, wet conditions when mineralization is slow.) Historically, sulfur was deposited in large quantities from rainfall primarily due to burning of fossil fuels. However, emission standards have resulted in a sharp decrease in sulfur deposition from the atmosphere. As this trend continues, coupled with higher yielding crops, sulfur fertilization may become more important in the future.

    Three-Year Total Sulfur Deposition

    Figure 1. Sulfur deposition maps from 2000-2002 and 2015-2017 (USEPA, 2019).

    A common question these days, is ‘Do I need to fertilize with sulfur?’ Table 1 summarizes on-farm sulfur trials conducted in Ohio from 2016 through 2019. Overall, only one trial (out of eight) resulted in a yield increase due to sulfur application (3 bu/acre in soybean). In addition to these on-farm trials, sulfur (applied as gypsum) did not increase yield in sixteen different environments across Ohio in studies conducted in 2013 and 2014. Lack of yield response is likely due to soils with organic matter levels >1%. (In our sixteen-environment study, soil organic matter levels ranged from 2.0 to 5.1%).

    Table 1. Summary on on-farm sulfur trials in corn and soybean from 2016-2019.




    Sulfur Source, Rate, and Timing

    Yield Response?





    Thio-sul at V3


    Nate Douridas (eFields report)




    Thiosulfate, 20 lb S/acre, starter

    +3 bu/acre

    Jason Hartschuh (eFields report)




    AMS, R1 and R3


    Sam Custer

    (eFields report)






    Sam Custer

    (On-Farm Report)






    Sam Custer

    (On-Farm Report)




    Ammonium thiosulfate, 20 and 40 lb S/acre, starter and sidedress)


    Sam Custer

    (On-Farm Report)






    Clifton Martin & Van Slack

    (On-Farm Report)






    Sam Custer

    (On-Farm Report)

    Sulfur deficiency symptoms are similar to nitrogen, but unlike nitrogen, chlorosis (yellowing) is more visible on newer, upper leaves. If you think your crop is deficient in sulfur, plant tissue testing is the best way to assess. (Sulfur soil analysis is not recommended.) If possible, collect plants exhibiting deficiency symptoms and also plants not exhibiting deficiency symptoms for comparison.

  6. Learn More about eFields at Regional Meetings

    Have you been enjoying the 2019 eFields Report and are excited to learn more? The Ohio State Digital Ag team is hosting six regional eFields meetings this winter. Join us to learn more about the eFields program and results we are seeing across the state. Each meeting will feature presentations highlighting local trials including seeding rate, nutrient management, and crop management. There will be a panel discussion featuring cooperating farmers who are conducting on-farm research with Ohio State Extension. We would also like to hear from you about what topics you are interested in seeing in eFields in the future.

    There is no cost to attend; for more information or to register for a meeting, visit go.osu.edu/eFieldsMeeting. Please plan to join us for the meeting nearest you:

                Southwest Region: February 10th, 9AM-12PM, Wilmington

                Northwest Region: February 26th, 9AM-12PM, Bryan

                Central Region: February 27th, 9AM-12PM,

                South Central Region: March 9th, 9AM-12PM, Circleville

                East Region: March 10th, 6-9PM, Coshocton

                West Central Region: March 16th, 9AM-12PM, Piqua

  7. H2Ohio Meetings Scheduled for February

    Author(s): Glen Arnold, CCA

    The Ohio Department of Agriculture is rolling out the H2Ohio plan this month at eight meetings in the Maumee River Watershed. Farmers living in the following 14 northwest Ohio counties will be eligible to apply for funds at their local Soil and Water Conservation Districts (SWCD) starting this week: Allen, Auglaize, Defiance, Fulton, Hancock, Hardin, Henry, Lucas, Mercer, Paulding, Putnam, Van Wert, Williams, and Wood. Soil and water Conservation Districts will be the first contact for farmers interested in the available funding.

    There is a series of meetings in February for farmers to learn more about the program.

    Meeting dates and locations are:

    February 4
    3 p.m.
    Owens Community College
    Veterans Hall
    30335 Oregon Road

    February 5
    2 p.m.
    Delphos Eagles
    1600 E. 5th Street

    February 5
    6 p.m.
    Defiance K of C Hall
    111 Elliott Road

    February 11
    6 p.m.
    Auglaize Co. Jr. Fair Bldg.
    1001 Fairview Drive

    February 18
    6 p.m.
    American Legion Hall
    601 N. 2nd St.

    February 20
    6 p.m.
    Fogle Center
    815 E. Mathias St.

    February 27
    6 p.m.
    Kissell Community Bldg.
    509 N. Main Street
    West Unity

    February 28
    9:30 a.m.
    Ohio Northern University
    McIntosh Center
    525 S. Main Street

    Farmers are strongly encouraged to contact their local SWCD offices by March 31st to get the process started. A Voluntary Nutrient Management Plan is required and only farm fields with soil phosphorus test levels of 50ppm (Bray P-1) or lower will be eligible for funded practices. The first seven practices eligible for funding are: Nutrient Management Plans, Variable-Rate Fertilizer, Subsurface Nutrient Application, Manure Incorporation, Conservation Crop Rotation, Cover Crops, and Drainage Water Management.

    The website to learn more about the program and the practices being funded is http://h2.ohio.gov/

  8. Fertilizer Applicator Certification Training

    A three-hour fertilizer certification program will be held in Richwood for any private or commercial applicator who needs to obtain fertilizer certification for the first time.  This training will be held at Richwood Marketing, 15 E. Ottawa Street, Richwood, Ohio on Wednesday, February 12.  The class will begin at 1:00 and end at 4:00 pm.  There is a $30 class fee payable to OSU Extension for this training.

    Please arrive early so that materials can be distributed and the program can start on time.  This training will meet the fertilizer certification requirements for those with and without a pesticide license.  Pre-registration is suggested by calling the Hardin County OSU Extension office at 419-674-2297 or the Union County Extension office at 937-644-8117.  Online registration is available at https://nutrienteducation.osu.edu/NutedWC.

    Agricultural fertilizer applicator certification is required in Ohio for farmers who apply fertilizer to more than 50 acres of agricultural production grown primarily for sale. This requirement was signed into law in June 2014, and also requires certification for commercial agricultural fertilizer applicators.  Farmers who have their fertilizer applied by co-ops or custom applicators are not required to be certified.

    Applicators who are a Certified Crop Adviser (CCA) or Certified Livestock Manager (CLM) are not required to attend the training.  Fertilizer is defined for the regulation as any substance containing nitrogen, phosphorus, potassium, or other plant nutrient in a dry or liquid formulation.  All application types such as broadcast, side dress, sub-surface, knifing and other are included in the certification requirement.  Lime and limestone are not included as fertilizer for the certification and farmers who only use starter fertilizer in their planter boxes are exempted.

    The agriculture fertilizer certification is not required for manure applications, unless farmers are applying livestock or poultry manure from a Concentrated Animal Feeding Facility (CAFF).  In this case, they would need to have either the CLM or Ohio Fertilizer Certification.

    The Ohio Department of Agriculture is the agency issuing the certification for agriculture fertilizer applications.  Once an applicator completes the fertilizer training, the ODA will bill them $30 for their fertilizer certificate unless the applicator currently holds a pesticide applicator license.

    The ODA website has information regarding the regulation at agri.ohio.gov.  For more information about other training sessions or general materials for the agriculture fertilizer certification, visit nutrienteducation.osu.edu or contact Mark Badertscher, Hardin County OSU Extension at badertscher.4@osu.edu or Wayne Dellinger, Union County OSU Extension at dellinger.6@osu.edu.


  9. 2020 Agronomy School: The Nuts & Bolts of Corn & Soybean Production

    Corn and soybeans
    Author(s): John Barker

     The 2020 Central Ohio Agronomy School will be held on Monday evenings, beginning on Monday February 10 through Monday March 9, from 6:30 –9:00 p.m. in the conference room of the Ag Services Building, 1025 Harcourt Rd. Mt. Vernon, Ohio 43050.   This five-week program will provide the attendees with the most comprehensive, up-to-date crop production and agricultural technology information available today.  This school is designed with everyone in mind; part-time or full-time producer, beginner or CCA agronomist.  Within each subject area we will teach the basic concepts and progress to the most advanced agronomic principles.

    Topics include:

    February 10   - Bruce Ackley, OSU Weed Science.

                                        Weed Identification with Live Plants at Various Growth Stages.

                                        Palmer, Waterhemp, Pigweed, Marestail, Various Grasses and more!

                            - Dr. Mark Loux, OSU Weed Science

                                      Developing a Multi-Year Herbicide Program for Tough to Control Weeds 

                                      Weed control update for 2020

    February 17   - Dr. Scott Shearer, OSU Chair, Food, Agriculture and Biological Engineering

                                        Field Compaction Research

                          - Dr. Elizabeth Hawkins, Field Specialist, OSU Extension

                                        2019 On-farm Research Results 

    February 24   - Ben Brown, OSU College of Food, Agriculture, & Environmental Sciences

                                        Farming & Marketing in an Uncertain World

                            - Peggy Hall OSU Agricultural & Resource Law Program

                                          “Hot” Agricultural Law Topics 

     March 2         - Glen Arnold, Field Specialist, OSU Extension

                                         Is Manure Right for You?

                            - Dr. Jeff Stachler, OSU Extension – Auglaize County

                                        Weed Seeds in Manure. 

     March 9         - Marne Tichenell, Wildlife Specialist, OSU Extension   

                                        Wildlife Damage in Field Crops

                            - Aaron Wilson, Byrd Polar and Climate Research Center

                                        How Weather is Affecting our Farming Operations

                                        2018 Weather Outlook

    This school will provide:

    14 continuing education credits (CEU’s) for Certified Crop Advisors,

                            C.M. 2, I.P.M. 6.5, N.M 2, P.D. 1.5,  S&W 2.0.

    8 hours of Commercial Pesticide Credits

                            Core - 2 hrs., 2a - .5 hrs., 2c – 2 hrs., 2d –.5 hrs., 9 - .5 hrs., 10c - .5 hrs., 15 – 2 hrs.          

    8 hours of Private Pesticide Recertification Credits

                            Core – 2 hrs.,  Cat 1- 2.5 hrs., Cat 2 - .5 hrs., Cat 6 - .5hrs., Cat 7 - .5 hrs., Cat 15 – 2 hrs.

    Registration costs vary due to CUE credits and pesticide applicator credits.

    This program is sponsored by The Ohio State University Extension, Advantage Ag & Equipment, B&B Farm Service, Central Ohio Farmers CO-OP, Channel, Clark Seeds, Cubbage Electric, Farmcredit, First-Knox National Bank, and Seed Consultants.

    For more information contact the OSU Extension Office in Knox County (740-397-0401).  The following links will provide more information for this program.  http://u.osu.edu/knoxcountyag/ or https://knox.osu.edu/

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.


Amanda Douridas (Educator, Agriculture and Natural Resources)
David Marrison (Educator, Agriculture and Natural Resources)
Dennis Riethman (Educator, Agriculture and Natural Resources)
Eric Richer, CCA (Educator, Agriculture and Natural Resources)
Garth Ruff (Educator, Agriculture and Natural Resources)
Jason Hartschuh, CCA (Educator, Agriculture and Natural Resources)
Jeff Stachler (Educator, Agriculture and Natural Resources)
Mike Gastier, CCA (Educator, Agriculture and Natural Resources)
Sam Custer (Educator, Agriculture and Natural Resources)
Sarah Noggle (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.

CFAES provides research and related educational programs to clientele on a nondiscriminatory basis. For more information, visit cfaesdiversity.osu.edu. For an accessible format of this publication, visit cfaes.osu.edu/accessibility.