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Agronomic Crops Network

Ohio State University Extension


C.O.R.N. Newsletter: 2016-19



    The outlook for July calls for above normal temperatures to persist. Maximum temperatures will generally be in the 80s and lowers 90s but a few day could top out as high as 95 especially in western and southern areas of the state. Overnight lows will range form the 50s to 70s but more days will be in the 65-75 degree range than higher or lower. More of the above normal temperatures in July will come from higher night-time lows versus daytime highs.

    Rainfall will be highly variable. There will be a ring of fire across the region which is a battle between the hot and humid weather south and cooler and drier air north. This will lead to complexes of storms from time to time. There will be a round of these storms from July 6-8 then again at some point in the week of July 11-15. The preferred area seems to be the southwest half of the state over the northeast half. Drought is forecast to expand some over northeast areas of the state.

    Overall, rainfall is forecast to be 0.50 inches to 2+ inches in the first half of July. Normal is near or just below 2 inches.

    In summary, July will be warmer than normal with normal to below normal rainfall overall but rainfall will be highly variably with drier areas likely northeast and wetter areas southwest.

    August will see more of the same.

    The NOAA/NWS/Ohio River Forecast Center rainfall outlook through mid-July is shown in the graphic.

  2. Is it Phytophthora stem rot? Is it flooding injury? Or is it both?

    Author(s): Anne Dorrance

    It can take a while for some pathogens to develop symptoms and impact their hosts, and by the end of last week (June 29/30th), reports were coming in on dying plants from the areas of the state that received 2 to 5 inches of rain during the week of June 20th.  Technically this is called the latent period, from the time of infection until symptom development or sporulation (the next generation of spores that are ready to infect the crop).  Phytophthora stem rot was evident in many of our historical fields that did not have the full resistance package.  Symptoms include dying plants, wilting and a characteristic root rot and brown coloration at the base of the stem. The key here is the root rot and the decay moving up the stem.

    Symptoms on young seedlings (left) and older plants with characteristic brown canker


    In Ohio, the Rps genes will only give some protection.  Ohio’s Phytophthora sojae populations have adapted to all of the Rps genes that are commercially available.  Rps1a, first deployed in the 1960’s is no longer effective, and like an elephant once it recognized this gene it does not seem to want to forget it.  This is challenging because we would like to be able recycle Rps genes periodically, but this is not going to be possible for Rps1aRps1c, Rps1k, and Rps3a are now recognized by the P. sojae populations across the state – but not every individual in every field.  So we recommend to continue to utilize them.  Rps8 is recognized by P. sojae populations in the southwest corner of the state – although it is still holding in the rest of the state.  What is needed is to give these genes a bit of backup – they need their guards, defensive team and that is with partial resistance – companies have been calling this field tolerance.  The Rps genes are like the star player on the basketball team that can hit the 3 point shots or the pitcher – but they can’t win the whole game on their own!  Every company uses a different scoring system – most are on a 1 to 9 scale where 1 is perfect growth, no root rot (this is for the Rps genes) and 9 is dead.  OR they use a 9 to 1 scale where 9 is no disease and 1 is totally dead.  You must read the fine print.  On the OSU scale – (1 is no disease and 9 is dead) a scores of 3 to 5 are optimum for providing a protection to the soybean plant during the mid-season.  When soybean varieties have this score – we have never observed Phytophthora stem rot in the field. 


    Flooding injury – Laura Lindsey gave a nice explanation in last week’s C.O.R.N. on how this can occur.  Symptoms of flooding injury will also occur on the roots, the outside cortical tissue can easily be pulled off leaving white “rat tails” or the correct term the root steles.  The Rhizobium nodules will be dead, not pink and overall poor health.  I have seen plants recover from flooding injury, the weather over the weekend, cloudy and cool was perfect.  Some of these areas may recover, it just depends on how long the field was saturated. 

    Flooding injury with white roots – the outer root tissue can easily be pulled off (left)  and a root with healthy Rhizobium nodules


    As you can probably tell, the conditions that can cause flooding injury in soybean are the same as Phytophthora.  Phytophthora is a watermold and requires saturated soils to produce the swimming zoospore that can find and infect plants.  When a susceptible variety is grown in the fields that have these flooding events, it is a double hit and even more important that the right protection was used.  For this week, on those fields that received the flooding rains, walk them.  Flooding injury will be in pockets where the water sat for a long period of time – then move to the other areas, to see if your Phytophthora package worked.  If you find the wilting yellow and dying plants then you need to rethink your Phytophthora management.  Work with your seed dealer to get a better package for the fields on your farm – and the focus should be not on the Rps gene but on the partial resistance side of the package.

  3. Western Bean Cutworm Flight is Beginning and Concerns for Late Planted Corn

    Author(s): Andy Michel,

    Here comes another season of western bean cutworm trapping!  Western bean cutworms (WBC) emerge as adults from late June until August, with peak flight usually occurring the 3rd week of July.  After mating, they lay eggs in corn, and the developing larvae may eventually enter the ear to cause significant ear damage.  While our trap catches have increased slightly over the past few years, we have been noticing an increase in damage, some of which may be economic.  WBC prefers to lay eggs in pre-tassel corn—so any corn that does not develop tassels over the next 2 weeks is at high risk for western bean cutworm infestation.  We have a lot of late planted corn, so good scouting is important!

    Egg masses are the most important stage to scout corn. Eggs are laid on the upper surface of the top 1-3 most leaves, especially those still in the vertical position.  Egg masses are usually in clumps of 25-100, start out white, then, within 24 hours of egg hatch turn dark purple.  After hatching, the larvae will feed on the tassel and pollen before entering the ear.  Once they enter the ear, they are mostly protected from insecticides, so spraying, if necessary should occur after egg hatch. Thresholds are based on inspecting 20 plants in 5 locations, and if 5-8% of the corn has egg masses, treatment is necessary. Many insecticides have efficacy against WBC. Furthermore, Bt products with Cry1F or Viptera will provide control; however we have noticed a fair amount of feeding with Cry1F in our trials. While it may protect against economic losses, these fields should be scouted as well. Further information can be found in our fact sheet ( and a free article in the Journal of Integrated Pest Management (

  4. Agronomy Field Day at South Charleston

    Producers and industry agronomists are invited to attend the Western ARS Agronomy Field Day, Wednesday, July 20, 2016 – 9AM to 3:15PM.   

    We plan to start registration at 8:30. With the program starting at 9 AM. Speakers planned for the day include:

    • Peter Thomison – Season outcomes for Corn, the good the bad and the ugly
    • Pierce Paul & Anne Dorrance – too dry for diseases? Try again.
    • Mark Loux – A lively discussion of herbicide tolerant crops will ensue.
    • Kelley Tillmon – Insects keep creeping up on our crops – what’s here for 2016?
    • Precision Ag questions? – we expect John Fulton and his high-speed planter and Alex Lindsey to talk about crop sensors as well.

    We’ll have a BBQ box lunch after the morning activities then continue into the afternoon until about 3PM.

    Pre-registration required by July 15th, lunch is included - $20 per person payable on site.

    Location: 7721 South Charleston Pike, South Charleston, Ohio 45368

    This is 3.5 miles northwest of South Charleston. Just south of I-70 on State Route 41 between Springfield and South Charleston in Clark County.

  5. Pesticide Applicator Field Day

    Private and Commercial pesticide applicator license holders can receive recertification credits on July 22 at a hands-on field day. This on-farm field day in St. Paris, Ohio will feature state specialists and in-field training on pesticide education.

    Dr. Pierce Paul, Extension State Specialist in corn and wheat disease will cover corn disease management options and strategies. Dr. Mark Sulc, Extension State Specialist in forages will discuss current research on insects in alfalfa and Dr. Curtis Young, Extension Educator in Van Wert County will provide an update on grain bin fumigation and sanitation. Mary Griffith and Amanda Douridas, Extension Educators in Madison and Champaign counties, respectively, will walk through reducing spray drift and sprayer calibration.

    Those who do not need credits are welcome to attend and take advantage of this opportunity to learn from specialists in a local setting.

    The field day will be held at Case Family Farms (1400 Kite Rd, St. Paris, OH 43072) from 8:45am until noon. Private applicators will receive recertification for licenses expiring 2017-2019 in categories Core, 1, 2 and 6. Commercial applicators can earn partial recertification credits in categories 2A and 10C. Three hours of Integrated Pest Management Certified Crop Advisor credits will be offered as well.

    The cost to attend is $10 and registration is due by 7/18. For more details and the registration form, see the event listings in the newsletter edition or visit:

  6. Northwest Ohio Precision Ag Sprayer Clinic and Recert - August 9th

    Author(s): Eric Richer, CCA

    Farmers, retailers and crop consultants interested in seeing the latest sprayer equipment and precision application technology for commercial agriculture are encouraged to attend the Tuesday, August 9th NW Ohio Precision Ag Sprayer Day at the Fulton County Fairgrounds, State Route 108, Wauseon. The event will offer 3.5 hours of commercial and private pesticide recertification credits in CORE and categories Private 1 and Commercial 2c. The program is also approved for 3.5 hours of Michigan pesticide applicator credits. The event will also offer five hours of Certified Crop Advisor credits.

    This event is from 8 a.m. to 3:30 p.m. and open to the public.  Registration is $25 prior to August 1st or on site for $40.  For a complete agenda and registration form, click here. The Fulton County Fairgrounds are located at 8591 State Route 108, Wauseon, OH 43567. Questions related to this program can be directed to or call the Fulton County OSU Extension office at 419-337-9210.

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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, CCA (Educator, Agriculture and Natural Resources)
Andy Michel (State Specialist, Entomology)
Anne Dorrance (State Specialist, Soybean Diseases)
Bruce Clevenger, CCA (Field Specialist, Farm Management)
Eric Richer, CCA (Field Specialist, Farm Management)
Greg LaBarge, CPAg/CCA (Field Specialist, Agronomic Systems)
Jason Hartschuh, CCA (Field Specialist, Dairy & Precision Livestock)
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)
Nathan Douridas, CCA (Farm Science Review Farm Manager)
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)
Wayne Dellinger, CCA (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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