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Agronomic Crops Network

Ohio State University Extension


C.O.R.N. Newsletter: 2014-22

  1. Weather Update


    The outlook for the remainder of July calls for below normal temperatures and normal to slightly wetter than normal conditions.

     After areas of rain to start the week of July 14 it will dry out and turn much cooler than normal with temperatures 5-10 degrees below normal. Growing degree days as a result will slow as well. By the middle of this week lows will be in the upper 40s to low 50s with highs in the upper 60s and lower 70s.

     Some scattered rain will return Friday and Saturday with a return to normal temperatures.

     For the week of July 21, temperatures will start above normal with highs 85-90 and lows 70-75. By the end of next week highs will once again only be in the 70s to near 80 and lows in the 50s to near 60. Some more rain will occur early to mid week ahead of a cold front.

     August looks warmer and drier than June or July but still not far from normal.

     Autumn outlook is still looking a little cooler and wetter than normal. The wetter conditions could impact harvest.

     Early indications are winter starts colder and wetter and ends warmer and drier which would be opposite recent winters.

     You can stay on top of the NWS Ohio River Forecast Center monthly and seasonsal hydrologic outlooks at:

  2. Insects in Soybean

    Japanese Beetles on Soybean Plants
    Author(s): Andy Michel

    Last week, I had a chance to scout some very early planted soybean that was in the R1 and R2 stages. A couple of observations:

    Japanese  beetles and other defoliators: There was a presence of general defoliators in soybean. Our two most common insects are bean leaf beetles and Japanese beetles.  While the BLBs were fairly hard to find, Japanese beetles were easier to spot. However, most of the defoliation was light and only present on the top leaves.  Remember—it takes a fair amount of defoliation before soybean yield is impacted. The thresholds for defoliation are 40% before bloom, 15% bloom to pod-fill, and 25% after pod fill.  But also keep in mind that these thresholdsare based on the whole plant, not just the upper portions. Additionally, most Japanese beetle defoliation occurs along the edge, so make sure you check the entire field.

    Stink bugs: Surprisingly, I collected a fair amount of green and brown stink bug adults, as well as some stink bug egg masses.  These eggs will hatch about the time soybean enters the pod stage, where they will then feed on the developing seed. While we are not at the time where a spray would be necessary, all soybean fields will need to be scouted over the next week for the continued presence of stink bugs.  

  3. Western Bean Cutworm Flight is Increasing

    Author(s): Andy Michel

    Our trap counts of Western bean cutworm (WBC) adults have been on the rise during the last week, and will likely increase until the end of July.  Just like in previous years, our hotspots for western bean cutworm activity are in NW and NE Ohio. Based on these counts, we would recommend growers scout for the presence of any WBC egg masses.  We know that females prefer to lay eggs in corn that has not tasseled, so those fields should take priority.  Egg masses are laid on the uppermost 1-2 leaves, especially those that remain in the vertical position. Scout 10 plants in 10 locations. Egg masses contain 25-75 eggs and start out white, then tan and then turn purple.  Once eggs turn purple, egg hatch will occur within 24 hours.  Treatment is recommended when 5% or more plants have egg masses.  Although we have yet to see economic populations of WBC, we do have a fair amount of pre-tassel corn that is at risk.  See fact sheet for more information.

  4. Foliar Fungicide Application in Field Corn - A 2014 Update

    Author(s): Pierce Paul

    Corn in Ohio is all over the board in terms of growth and development, ranging from V6 to R2. Late-planted fields are usually at greater risk for foliar disease development, and reports coming in from across the state indicate that gray leaf spot is already present on the lower leaves in some areas. The conditions we have had over the last few weeks have certainly been favorable for foliar diseases. Gray leaf spot (GLS), the number one foliar disease of corn in the state, develops best at temperatures between 70 and 90 F, especially when conditions are consistently wet and humid. For GLS infection to occur, the leaf surface needs to be wet for 11 to 13 hours and relative humidity in the canopy needs to be at or above 90% for an uninterrupted period of 12 to 13 hours. On the other hand, northern corn leaf blight (NCLB), a disease that has been increasingly prevalent in the state over the last few years requires wetter and slightly cooler conditions.            

    Questions and Answers on fungicide use in field corn

    Question 1. When really should I apply a fungicide for disease control in field corn?

    Answer 1. You should first scout for foliar diseases:

    Just prior to tassel emergence, plants should be examined for disease symptoms. For residue borne-disease such as gray leaf spot and northern corn leaf blight, a foliar fungicide application should be considered under the following situations:

    • Susceptible hybrids:  If disease symptoms are present on the third leaf below the ear or higher on 50% of the plants examined.
    • Intermediate hybrids:  If disease symptoms are present on the third leaf below the ear or higher on 50% of the plants examined, AND the field is in an area with a history of foliar disease problems, the previous crop was corn, and there is 35% or more surface residue, and the weather is warm and humid through July and August.
    • Resistant hybrids:  Fungicide applications generally are not recommended. 

    Question 2. Do foliar fungicides really increase yield in field corn when there is not disease?

    Answer 2. Fungicides MAY indeed lead to an increase in yield in field corn, but the yield response is HIGHLY variable. The greatest and most consistent increases in yield are usually seen when foliar diseases are present and at high levels on susceptible hybrids.  

    Question 3. What about yield increase in stressed corn?

    Answer 3. I know of no research data showing conclusively that fungicides lead to higher yields in corn under stress conditions, other than when the stress is caused by diseases. To conclusively say whether or not a given fungicide increases yield in stressed corn, you will need to compare treated and non-treated, stressed and non-stressed corn in the same field, planted with the same hybrid, all exposed to the same set of weather, soil, and crop production conditions. In addition, such a comparison will need to be made over multiple years and locations.

    Question 4. What about the economics? When will the fungicide pay for itself?

    Answer 4. It depends mainly on grain price, fungicide cost, application cost, hybrid susceptibility to disease, and the level of disease in the field. You are most likely to see a return on your fungicide investment when grain prices are high, fungicide and application costs are low, the hybrid is susceptible, and disease levels are high. For instance, if we assume that it cost between $20 and $36/acre to put on a fungicide treatment (product plus application) and grain prices range from $7 to $9/bushel, you would need at least a 3-4 bushel increase in yield for the fungicide to pay for itself. Over the last three years, our data have shown that when fungicides are applied in the absence of foliar diseases, the yield increase is greater than 3 bushels/acre 45% of the time. In other words, there is less than a 50% chance that the fungicide will pay for itself when applied in the absence of foliar diseases. As the price for grain decreases and/or application cost increases you will need more than a 3 bushel increase in yield for a fungicide to pay for itself.                 

    Question 5. Do fungicides increase yield by affecting respiration, photosynthesis and other physiological processes?

    Answer 5. Yes, some fungicides do indeed affect crop physiology. However, most of these effects have been observed in the greenhouse, under controlled conditions. In the field where conditions are highly variable, a greening effect is sometimes seen when strobilurin fungicides are used, however, the association between this greening effect and grain yield is not clear or consistent. Remember, the biggest drivers of yield are hybrid genetics, weather conditions, and crop nutrition, not fungicide application in the absence of disease.

    Summary results from 8 years of fungicide research - up to 172 trials

    Fungicides tested: Headline, Stratego, Quilt and Quadris. All fungicides were applied at VT (tasseling) or at R1 (silking).

    Average yield range: 164 to 197 bushels/acre.

    Yield difference between fungicide-treated and untreated plots: In 28 to 48% of the trials, yield was higher in the untreated plots than in the fungicide-treated plots. These clearly show how highly variable yield responses are to fungicides.   

    Average yield difference between fungicide-treated and untreated plots: 3.6 to 6.2 bushels/acre.

    Average yield difference between fungicide-treated and untreated plots when foliar disease levels are low (<5%): 1 to 5 bushels/acre.  

    Average yield difference between fungicide-treated and untreated plots when foliar disease levels are higher (> 5%): 7 to 10 bushels/acre.

  5. Modified Relay Intercrop Soybeans in a Twin Row System

    Twin row wheat with interseeded soybeans just prior to harvest.

    After 15 years of growing 10 inch row wheat and soybeans in a Modified Relay Intercrop  (MRI) system, this year wheat and soybeans were planted into two different row spacing/ cropping systems. Soybeans were intercropped into wheat (much earlier than in past years – 5/23 at one site) into a twin row system (two 8 inch wheat rows and a 22 inch skip) and a 15 inch row system.

    Results of 10 inch row intercropping (average over all replicated trials) after 15 years were:  76 bushels per acre for wheat and 30 bushels per acre for soybeans.  However, MRI soybean yields have not been as consistent from year to year as soybeans grown in a conventional mono crop system.   With wide row wheat (15 inch) yielding relatively well in OSU Wheat Performance trials (go to: ), the focus was on improving soybean yield via the aforementioned wheat row/cropping systems.  

    In evaluation of MRI soybeans in a twin row wheat system, a few observations follow after wheat harvest: 1. Soybeans planted into wheat  (2 rows into each 22 inch skip) on  May (5/23) grew well and are  the  R1 to R2 stages of growth  with a height of up to 18 inches in some plots. 2. This year with twin row wheat harvest occurring on July 11 (waiting for wheat to dry), soybeans were clipped with up to 2 fully expanded trifoliate leaves lost which probably will not be desirable.  Thus in an interseed system, we would recommend not to wait to harvest wheat until dry (ie 13.5%). Some elevators have a “wet wheat program” that may permit growers to harvest wet wheat and deliver it. 3. We would recommend interseed system wheat be planted close to the Hessian Fly Free date to promote/allow maximum wheat tillering in the fall and early wheat maturity (harvest in the summer).  Follow appropriate seeding rates, fertility recommendations, weed control and seed treatments for wheat and soybeans.  4. Soybeans that are very tall and in early reproductive stages are easily killed by wheel traffic (another reason to harvest wheat at higher moisture). 4. Finally, combine wheel traffic has been very damaging to all MRI soybeans regardless of system being used (10, 15,  or twin row) and will reduce soybean stands/yields. 

    For more information on 2013 MRI trials go to the Crop Production for Profit blog at:

  6. Manure Boom Application Field Day July 18th

    Paulding County will be the site for a Dairy Manure Research Technology Day on Friday, July 18, 2014 at 2:00 PM.  Research is being conducted based upon using dairy manure as a fertilizer source for corn and/or corn silage.  The nutrient boom is a new technology being developed to apply dairy manure to standing corn in the tasseling stage.  During the technology day, the manure nutrient boom will be in operation for live demonstrations.  The application of manure to a growing corn crop can expand the manure application window for livestock producers while improving corn and silage yields.

    The field day will be held at the corner of township road 60 and county road 67 near Payne, Ohio. The site is a research plot comparing corn fertilized with commercial fertilizer to corn fertilized with a reduced amount of commercial fertilizer plus fertilizer from the dairy manure.

    The boom applicator applies approximately 350 gallons per minute and covers 48 rows of corn with each pass. The boom is pulled across the field using a Cadman hard hose system. A frac tank allows manure to be delivered to the field from semi-tankers and the pumps on the frac tank can supply manure for two nutrient booms running at the same time.

    Certified Livestock Manager (CLM) credits and Certified Crop Advisor (CCA) credits have been applied for participants attending the event. Contact the Paulding County Extension Office at (419)399-8225 extension 25 for more information.

    The flier for this event is available here:

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.


Anne Dorrance (State Specialist, Soybean Diseases)
Ed Lentz, CCA (Educator, Agriculture and Natural Resources)
Eric Richer, CCA (Field Specialist, Farm Management)
Greg LaBarge, CPAg/CCA (Field Specialist, Agronomic Systems)
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)
Sam Custer (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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