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Agronomic Crops Network

Ohio State University Extension


C.O.R.N. Newsletter: 2016-24

  1. Early Autumn Weather Outlook


    All data suggests above normal temperatures will persist into autumn. However, it should be noted that the above normal temperatures will be driven more from the night time lows than daytime maximum temperatures. This means we do not expect many days above about 90 for the maximum temperatures. So that is some good news.

    There is also some more good news. There are rain chances in the next 7-10 days across Ohio. However, confidence is low on the placement of rainfall. It appears the heaviest rain will be along and east of Interstate 71. Rainfall totals of 1-3 inches are possible east of I-71 the next 2 weeks. Normal rainfall is about 1.5 to 2 inches inches so above normal rainfall is expected there. West of I-71 it is more unclear on how much will fall. We do expect rainfall but the further northwest in the state of Ohio the less. Indiana will see even less rainfall. Rainfall totals northwest of I-71 will be more common less than 1 inch than more. Isolated places could get limited amounts.

    The outlook for the rest of August calls for temperatures 1-5F above normal and rainfall below normal northwest half and normal or slightly above southeast half.  The outlook for September calls for continued above normal temperatures and rainfall at or below normal.  Evapo-transpiration will also continue at or above normal into September.

    Looking further ahead, the main pattern change from warmer and drier to cooler and wetter may not come until November or December as a possible La Nina influence kicks in.

  2. Bt Resistance in Western Corn Rootworm—The 3rd Shoe Has Dropped

    Western corn rootworm is a highly adaptable insect, and it was just a matter of time before we saw resistance to Bt traits designed to protect against root damage.  In the Western Corn Belt, growers have noticed many field failures due to heavy rootworm feeding. Most of this research was led by Dr. Aaron Gassmann’s laboratory at Iowa State University.  In 2011 they discovered resistance to Cry3Bb1 (which may be present in Yieldgard or Genuity traits). In 2014 they discovered resistance to mCry3A (which may be present in Agrisure traits).  Now, in 2016, they have discovered resistance to Cry34/35Ab1 (which may be present in Herculex or Optimum traits). For a full list of Bt traits see:  Remember that Bt against rootworm has only been available since 2003, and, in just 13 years, most of our major tools have been compromised.  Currently there is only one trait, eCry3.1Ab (present in Duracade traits), without any published reports of resistance.

    Luckily for Ohio growers, all these products are still effective against Western .rootworms in our state.  We have only heard of a few, scattered reports of field failures.  Observations from the Western Corn Belt indicate that a lack of rotation greatly increases the risk of Bt resistance.  Any field with corn grown from more than 3 straight years should be inspected for root feeding and proper trait performance. Dig 5 roots in 10 locations and use the 0-3 node injury scale to rate feeding (see this guide by Dr. Chris DiFonzo @ Michigan State University: Now is the perfect time to perform root digs—if you suspect field failures, please contact us at and or contact your extension educator.  Also remember that crop rotation remains our single, best tactic to prevent Bt resistance from occurring in Ohio.  If crop rotation is not possible, the next best alternative is to rotate different Bt traits each year or consider soil insecticides which are still quite effective. However, we do not see a need nor a benefit for combining both soil insecticides with Bt in Ohio.

  3. Reports of Frogeye Leaf spot in southern Ohio:. To spray or not to spray.

    Author(s): Anne Dorrance

    Late reports of frogeye developing on susceptible cultivars in southern Ohio.  So the next question is what to do.  During 2005-2008, we were able to measure a mean difference in yield of 5 to 10 bu/A when soybeans were treated at R3 in fields where frogeye was present.  We have also been able to measure a greater yield difference on highly susceptible varieties when frogeye was present during the early flowering stages.  However, last year, when frogeye was less than 1 spot per 40’ on a moderately susceptible variety, and the conditions were very dry and warm over the next 2 weeks, we could not measure any yield effect – although we could measure differences in the level of disease.

    Conditions for frogeye leaf spot are cooler (below 80 degrees F), heavy dews, and frequent rains.  Frogeye has a long latent period of 7 to 10 days, which is the time from infection to symptom development and sporulation.  Interestingly, it will only infect new foliage, not the older foliage in the lower canopy. 

    If frogeye can readily be found in the field, indicative a highly susceptible variety then:

    If your soybeans are in the later growth stages (R4 & R5 or greater), and the beans are finished flowering and beginning to fill, there is no need to spray.  What lesions will form will be few and will have little impact on yield.

    If your soybeans are at R3, they still have more growth to fill out, it is a high yielding field, rains and favorable conditions for infection, our data indicates that you should be able to measure yield differences of 5 bushels or greater. 

    The next question is which fungicide to use.  There are many populations in the region that are no longer controlled by the strobilurin fungicides.  Therefore, any fungicide that is used, should not be one of these, and that leaves primarily the triazoles.  They are all effective, so price of fungicide and application costs should be a consideration here.

    Finally, leave check strips. And leave at least 3 untreated strips and make notes on how much disease was present and the growth stage.  This will improve decision making in the future. 

  4. Warm Nights May Impact Corn Yield

    Author(s): Peter Thomison

    Weathercasters are calling for continued above average temperatures in August, especially higher night time temperatures. Past studies show that night time temperatures affect yield potential. High night temperatures (in the 70s or 80s degrees F) can result in wasteful respiration and a lower net amount of dry matter accumulation in plants. The rate of respiration of plants increases rapidly as the temperature increases, approximately doubling for each 13 degree F increase. With high night temperatures more of the sugars produced by photosynthesis during the day are lost; less is available to fill developing kernels, thereby lowering potential grain yield. High night time temperatures result in faster heat unit (GDD) accumulation that can lead to earlier corn maturation, whereas cool night temperatures result in slower GDD accumulation that can lengthen grain filling and promote greater dry matter accumulation and grain yields.

    Research at the University of Illinois conducted back in the 1960’s indicated that corn grown at night temperatures in the mid-60s (degrees F) out yielded corn grown at temperatures in the mid-80s (degrees F). Average corn yields are generally much higher with irrigation in western states, which have low humidity and limited rainfall. While these areas are characterized by hot sunny days, night temperatures are often cooler than in the Eastern Corn Belt.  Low night temperatures during grain fill (which typically occurs in July and August) have been associated with some of our highest corn yields in Ohio. The cool night temperatures may have reduced respiration losses during grain fill and lengthened the rain fill period. Cooler than average night temperatures can also mitigate water stress and slow the development of foliar diseases and insect problems.


    Hoeft, R.G., E. D. Nafziger, R.R. Johnson, and S.R. Aldrich. 2000. Modern Corn and Soybean Production. MCSP Publications, Champaign, IL. [see “Climate and Corn” section]

    Peters, D.B., J.W. Pendleton, R.H. Hageman, and C.M. Brown.  1971.  Effect of night air temperature on grain yield of corn, wheat, and soybeans.  Agron. J.  63:809.


  5. Spider Mites in Corn

    Normally we only worry about spider mites in soybean, but when conditions are just wrong they can impact corn as well.  Corn that has been treated with some fungicides and insecticides (particularly a broad-spectrum pyrethroid) are more likely to experience spider mite outbreaks under hot, dry conditions.  A general guide for treatment of twospotted spider mites in corn is 15-20% of leaf area covered in mite colonies, with continued dry weather expected.  Control is most likely to be economical from pre-tassel through soft dough, and unlikely to provide a return from dent onward. 

    Most-excellent field crop entomologist Chris DiFonzo at Michigan State has put together a nice table listing spider mite products for corn, soybean, dry bean, and sugarbeet.  Always check your labels!

  6. Contract Termination - The Big Data Confusion: Part 12

    Author(s): John Fulton,

    Termination signifies ending an obligation under a contract. Sometimes, terminating a contract can be a difficult process. Verbiage used within a contract about terminating can vary as it relates to the ability of the customer to cancel the contract or services being provided.  One should take the time to read contracts or agreements specific to termination and what it means to you as a user but also the company or agency, if you decide to cancel.  The 11th principle of the American Farm Bureau Federation’s “Privacy and Security Principles for Farm Data” includes Contract Termination stating that “farmers should be allowed to discontinue a service or halt the collection of data at any time subject to appropriate ongoing obligations. Procedures for termination of services should be clearly defined in the contract.”

    Contracts between farmers and their Agricultural Technology Provider(s) (ATPs) should clearly outline the provisions for cancelling a contract around data collection, storage, sharing and services being offered.  The ability to opt out of a contract is important along with knowing what happens to your data once a contract is terminated.  The principle of choice allows a farmer to be engaged in services and features offered by an ATP or data service provider plus extends to the ability of the farmer to choose to terminate his/her contract. Another important aspect to consider is the conditions in which the ATP or data service provider can terminate the contract.  Understanding the conditions that the company can terminate the contract could simply include not providing “all” your data or not actively using a digital tool.   If a farmer is unhappy at any time with the services, features, or other components of their contract(s) with an ATP, and assuming all ongoing obligations are being considered, they should be able to terminate.  It is recommended that the farmer thoroughly reads and understands the contract in which they are engaging in with an ATP.  Often, being proactive about concerns or questions relating to the contract (including services offered as well as each party’s rights and responsibilities), help to form and maintain a strong partnership that will provide for increased productivity and profitability through data management.

  7. Protect Water--Keep Nutrients in the Field

    Author(s): Mark Badertscher

    C.O.R.N. Newsletter readers interested in current research and what they can do to assist with the water quality and nutrient management issues happening in Ohio won’t want to miss ‘Agricultural Conservation, Protecting Water: Keeping Soil and Nutrients in the Field.’ This is the theme of the Hardin County Field Day on August 26.  This is the second year for this field day, cooperatively sponsored by the following partners: The Nature Conservancy, John Deere, Findlay Implement, Chris Kurt Farms, Randy Boose Farms, OSU Extension, Hardin & Putnam Soil and Water Conservation Districts, Ohio Farm Bureau/Blanchard River Demonstration Farms Network, Ohio Department of Agriculture and USDA Natural Resources Conservation Service.

    The event location will be approximately one mile south of Dunkirk, Ohio on US Route 68 and Township Road 50.  Parking will be at Randy Boose’s property and participants will ride a wagon to Chris Kurt’s farm for sessions.   Registration will begin at 8:15 am, with coffee and donuts provided by Ag Credit.  The field day activities will begin at 9:00 am, following a welcome by Hardin SWCD Chairman Jerry McBride.  Trailers will provide access to tents and field demonstrations that address several ag conservation and water quality issues.

    Concurrent sessions planned around the day’s theme include Soil Health by Dr. Hans Kok of the Indiana Conservation Cropping Systems Initiative; Phosphorus Removal Bed Construction by Dr. Jon Witter, OSU-ATI Assistant Professor of Agronomy and Soils; 4Rs of Nutrient Stewardship by Joe Nester, owner Nester Ag LLC, an independent crop consulting business and former agronomist; and New Fertilizer and Manure Application Rules for the Lake Erie Watershed by Clark Hutson, Ohio Department of Agriculture Area Program and Western Lake Erie Basin Specialist and Jocelyn Henderson, ODA Pollution Abatement and Resource Management.

    Other concurrent sessions planned include Two-Stage Ditches that have been installed in the Cessna Creek Watershed with the aim of reducing nutrient loads by Dr. Christopher Spiese, Assistant Professor of Chemistry, Ohio Northern University; Edge of Field Research: Phosphorus Movement in Surface Run-off and Drainage Discharge by Kevin King, United States Department of Agriculture, Agricultural Research Service; Nutrient Management On-Farm Research by Mark Badertscher, Agriculture and Natural Resources Educator, OSU Extension-Hardin County; and ‘What is Toledo Doing?’ to assist with the Water Quality Issues in Lake Erie by Andy McClure, Administrator of the City of Toledo Collins Park Water Treatment Plant.

    During lunch, Dr. Chris Winslow of Ohio State University’s Stone Laboratory at Lake Erie will address the ‘Current State of Lake Erie.’  Following lunch there will be Field Demonstrations of Technology and Equipment Options available from Findlay Implement Company for injecting fertilizer directly into the soil for incorporation using the John Deere 2510H toolbar with a dry fertilizer attachment and a Montag cart.  Legacy Farmers Cooperative will provide information about their minimum disturbance strip-till toolbar with a cover crop seeder.

    The Hardin County Field Day ‘Agricultural Conservation, Protecting Water: Keeping Soil and Nutrients in the Field’ requires participants to pre-register to ensure a lunch count for the event.  Please call the Hardin Soil and Water Conservation District at 419-673-0456, extension 3 by August 17 to attend this free event.  CCA and CLM credits are pending.

  8. FSR Agronomy College is September 13

    Agronomists , CCAs and custom applicators are invited to the Farm Science Review Agronomy College, hosted by the Ohio AgriBusiness Association in partnership with Ohio State University Extension and the Farm Science Review staff. The program will bring industry experts, OSU researchers, and agronomy service providers together to enhance collective knowledge and learning at the Molly Caren Agricultural Center in London, Ohio, on Sept. 13 - one week before the start of the annual three-day farm show.

    The full-day event features time with OSU Extension educators in the field at the small plot agronomy demonstrations. For the larger field demonstrations there will be topics including tip selection for the new herbicide tolerant crops, precision applications, remote sensing, and an update on nutrient management issues in Ohio. 

    CCA and pesticide application credits are also available to those attending.

    This is the second year the FSR Agronomy College will be held through the partnership between OABA and OSU Extension.

    Registration for the Agronomy College is $120 per participant. The event runs from 9 a.m. to 4 p.m., with on-site welcome and registration beginning at 8:30 a.m. To register or for more information, visit, call 614-326-7520 or email A flyer is also attached.

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 Bennett (Educator, Agriculture and Natural Resources)
Amanda Douridas, CCA (Educator, Agriculture and Natural Resources)
Ed Lentz, CCA (Educator, Agriculture and Natural Resources)
Eric Richer, CCA (Field Specialist, Farm Management)
Glen Arnold, CCA (Field Specialist, Manure Nutrient Management )
Greg LaBarge, CPAg/CCA (Field Specialist, Agronomic Systems)
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)
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)
Tony Nye (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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