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Agronomic Crops Network

Ohio State University Extension


C.O.R.N. Newsletter: 2022-18

  1. Prevent Plant Economics

    To avoid duplication, we do not make it a habit to cross-post articles from other publications. We assume that if you are interested in information from other newsletters and publications, you will subscribe to those. With that being said, we do want to direct your attention to the Ohio Ag Manager article “Evaluating the Prevent Plant Option” published June 9. If this situation applies to you, and you would like more information on the economics of this decision, please visit to read the article in its entirety.

  2. Time to Start Scouting for Potato Leafhoppers in Alfalfa

    We are receiving reports of near or at-threshold levels of potato leafhopper in alfalfa.  As second-cut alfalfa grows, farmers should scout for resurging numbers in their fields.  Younger alfalfa is more susceptible to damage at lower leafhopper numbers.  If alfalfa is more than 7 days from a cut and plants are under normal stress, a good rule of thumb for a treatment threshold is:  when the number of leafhoppers in a 10-sweep set is equal to or greater than the height of the alfalfa.  For example, if the alfalfa is 8 inches tall and the average number of leafhoppers per sample is 8 or higher, treatment is warranted. If the average is 7 or lower, the grower should come back within a few days to see if the population is higher or lower.   Vigorous alfalfa can tolerate higher numbers, and stressed alfalfa can tolerate fewer.  Special attention should also be paid to alfalfa fields that were damaged by fall armyworms last year.

    For a video on scouting techniques

     or visit

    For a video with detail on damage, ID, and control options 

    or visit

    Our extension factsheet on potato leafhopper in alfalfa is at

    A great resource for other forage-related questions is the Forage Page at

  3. REMINDER: Replanting Decisions in Corn and Soybeans… What to Consider

    Unfavorable weather during the months of April, May, and early June has negatively affected corn and soybean acres establishment in the state. If considering replanting fields, a C.O.R.N. Newsletter article released in mid-May has several steps and considerations that can help the decision.

    Read the article here:

    A picture containing ground, outdoor, plantDescription automatically generatedIf soil crusting/emergence is a concern, it may be more beneficial to consider using a rotary hoe to improve emergence than re-planting. For agronomic crops, we are approaching the period where gains in stands won’t offset yield losses caused by a shortened growing season. Other considerations are to consult with your crop insurance agent and seed company reps on any replanting policies or assessments required prior to implementing this practice.

  4. Corn Growth and Development: Crop Staging

    One of the bottom-line activities in growing crops should be understanding and keeping track of crop growth and development. Crop growth is related to the increase in size. It is influenced by factors such as temperatures, water availability, stress, competition, and fertility. Crop development relates to the progress in stages, and temperatures primarily drive it.

    Corn plants are first staged as vegetative (from emergence to tasseling) and then reproductive (from silking to physiological maturity). These vegetative or reproductive stages are assigned on a field basis when more than half of a subsample of plants are at the same stage. Despite different staging methods exist (e.g., horizontal leaf and leaf tip), the recommended is the Leaf Collar method for vegetative stages (V) and indicators of kernel development for reproductive stages (R) [Table 1].

    Table 1. Vegetative and Reproductive Stages for corn. Adapted from Abendroth et al., 2011.







    First Collared Leaf


    Second Collared Leaf


    Third Collared Leaf


    nth Leaf















    Physiological Maturity

    When it comes to crop management, one should focus on development as a more precise crop reference instead of growth. At later vegetative stages (after V10), younger leaves have often senesced, and the split-stalk approach may need to be taken to accurately stage plants (i.e., plants do not stay at the V12 stage until tasseling). This video shows staging using the split-stalk technique.

    From planting to physiological maturity, plant structures initiate and grow at different stages (Figure 1). In the case of modern hybrids, it is common to see silks emerge (R1) before tassels fully emerged (VT) as this can improve pollination. Adverse conditions such as drought, heat, off label applications during any of these processes can negatively impact the crop and ultimately affect yields.

    Corn growth and development figure

    Figure 1. Corn growth and development from planting and germination (G) to physiological maturity (R6). Brown arrows indicate the primary period, and gray arrows indicate possible variations for each event. Source: Ortez et al., 2022 (Crop, Forage & Turfgrass Management, accepted, in production).

    An adequate understanding of stages in corn is essential when planning different activities in the growing season—for example, fertilizer, herbicide, insecticide, and fungicide applications. Additionally, a good follow-through of corn staging can help understand when critical events occur, for example, drought stress linked to a reduction in kernel fill (i.e., kernel weight) towards the end of the season.


    Abendroth, L. J., R. W. Elmore, M. J. Boyer, & S. K. Marlay. (2011). Corn Growth and Development. PMR 1009. Iowa State University Extension, Ames, Iowa.

    Ortez, O., A. J. McMechan, T. Hoegemeyer, I. A. Ciampitti, R. L. Nielsen, P. Thomison, L. J. Abendroth, & R. W. Elmore. (2022). Conditions Potentially Affecting Corn Ear Formation, Yield, and Abnormal Ears: a Review. Crop, Forage & Turfgrass Management Journal (accepted, in production).

  5. Crops Under Water – Crop Stage is Critical for Recovery

    Looking down a windrow of cut alfalfa hay.

    Large rain events seem to be trending this year in many parts of Ohio, especially in Northwest Ohio where 3-5 inches of rain fell in 24-48 hrs. This can lead to standing water (flood) conditions or waterlogged soils (the root system is saturated). In some areas, this may have resulted in a partial and complete immersion of plants, especially in low spots, on river bottoms, and along streams. Many crops are sensitive to excess water, but the amount of damage is typically driven by plant growth stage, rainfall intensity, and duration of saturated/flooded conditions.

    Figure 1. Water standing in a corn field, V5 stage, on June 8, 2022. Franklin County, Ohio.In corn, waterlogged conditions from V4-V16 (Figure 1) can limit yield potential by reducing ear size, the number of kernel rows per ear, and also the potential number of kernels per row. Yield loss in corn can also be affected by Nitrogen (N) application. Corn waterlogged at the V4-V5 growth stage for 3-4 days reduced yield in Ohio trials by 25-45% when 100-120 lb N were applied pre-plant and no additional nitrogen was applied compared to non-flooded plots. On the plots that had pre-plant N applied, adding 60-120 lb N post-flooding resulted in yield losses of only 3-15% compared to non-flooded controls receiving the same N application regime. Nitrogen stress (losses or lack of uptake) at the time of flooding can result in greater yield loss compared to fields with adequate nitrogen; waterlogging for 3 days with 120 or 180 lb N applied entirely after flooding had 28 or 9% lower yield compared to non-flooded plots receiving the same N program. The later the flooding occurs in corn, the less impact it has on grain yield losses. Bacteria deposited in leaf whorls by flooding may also result in diseased and dead plants. Disease problems of greater risk due to ponding include corn smut, pythium, and crazy top. If plants are covered with mud due to the excess water, photosynthesis may be limited but it is unlikely that the photosynthetic capacity of leaves has been completely destroyed. Smaller amounts of rain can wash silt off leaves allowing for resumption of photosynthesis. It will also help wash mud out of leaf whorls allowing new leaves to emerge. Wet soil conditions may also increase susceptibility to root lodging of larger plants (approaching the V10 stage or later). For corn that’s emerged, check the color of the growing point to assess plant survival after flooding. It should be white to cream-colored, while a darkening and/or softening usually precedes plant death. For corn not yet emerged, evaluate the appearance and integrity of seeds or seedlings that have yet to emerge (likely rotting if discolored and softening). Also, check for soil crusting as the soil dries, and be prepared to use a rotary hoe in the event crusting is impending emergence. Look for new leaf growth 3 to 5 days after water drains from the field.

     Figure 2. Water standing in a soybean field. Symptoms of flood stress/saturated soils include yellow stunted plants.Soybeans tend to be more sensitive to flooding stress during the reproductive stages rather than during the vegetative stages. Flooding for up to 4 days may not impact seed yield if it occurs during the vegetative (V4-V5) stages. A flood duration of 7 days or more can decrease yield by 17% to 63% in soybeans if it occurs during the vegetative stages. However, a flood duration of 4 days or greater during reproductive stages (R2-R5) can result in significant yield loss (25% to 85%). Additionally, there is a wide range in varietal tolerance to flooding for soybeans, so every variety may not be impacted the same. A greater concern may be the incidence of oomycete infection for young soybean plants, and producers may be on the lookout for Phytophthora stem and root rot later in the season. If seed treatments were employed before planting, this could help minimize those issues. At the vegetative stage, symptoms of flood stress (saturated soil) include yellow stunted plants (Figure 2) and poor root growth and nodulation.


    Figure 3. Alfalfa field showing poor drainage between tile lines, Auglaise County, OH 2019. (photo by J. Stachler)Besides corn and soybean, forages can also be impacted by heavy rainfall events. The degree of injury is dependent on species, environmental factors, and when the crop was last harvested. Alfalfa (Figure 3) is particularly sensitive to waterlogging injury, especially under high light conditions. Damage from flooding can be most severe if it occurs shortly after cutting. Harvesting alfalfa 2 and 12 days before soil flooding reduced regrowth yield by 56% and 33%, respectively. Unharvested plants were not injured with a flooding duration of up to 14 days. Be aware of these interactions and allow extra recovery time if alfalfa is waterlogged soon after cutting. Waterlogged fields should also be protected from potato leafhopper injury to avoid pest damage on top of environmental stress, especially in seedling alfalfa stands. Also, be sure to delay forage harvesting operations until soils are firm enough to avoid permanent crown damage and stand loss that will plague you for the remaining life of the stand. Severely damaged alfalfa stands can be no-till interseeded with sudangrass to increase forage yield this year.

    While management options to address the flooding in the short term are limited, an understanding of the potential impacts can help producers to prepare and plan for management adjustment for the rest of the season. The excess water in crop fields has direct yield and economic implications.  


    Barta, A. L. 1988. Response of field-grown alfalfa to root waterlogging and shoot removal. I. Plant injury and carbohydrate and mineral content of roots. Agron. J. 80:889-892.

    Barta, A.L. and R.M. Sulc. 2002. Interaction between waterlogging injury and irradiance level in alfalfa. Crop Sci. 42:1529-1534.

    Barta, A.L,, R.M. Sulc, M.J. Ogle, and R,B.Hammond. 2002. Interaction between flooding or drought stress and potato leafhopper injury in alfalfa. Plant Health Progress 3:1,

    Cárcova, J., B. Andrieu, and M.E. Otegui. 2003. Silk elongation in maize: relationship with flower development and pollination. Crop Sci. 43:914-920.

    Dill, T.E., S.K. Harrison, S.W. Culman, and A.J. Lindsey. 2020. Grain yield response of corn (Zea mays L.) to nitrogen management practices and flooding. Plants 9:348.

    Kaur, G., B.A. Zurweller, K.A. Nelson, P.P. Motavalli, and C.J. Dudenhoeffer. 2017. Soil waterlogging and nitrogen fertilizer management effects on corn and soybean yields. Agron. J. 109:1-10.

    Lizaso, J.I., and J.T. Ritchie. 1997. Maize shoot and root response to root zone saturation during vegetative growth. Agron. J. 89:125-134.

    Oosterhuis, D.M., H.D. Scott, R.E. Hampton, and S.D. Wullschleger. 1990. Physiological responses of two soybean [Glycine max (L.) Merr] cultivars to short-term flooding. Environ. Exp. Bot. 30:85-92.

    Rhine, M., G. Stevens, G. Shannon, A. Wrather, and D. Sleper. 2010. Yield and nutritional responses to waterlogging of soybean cultivars. Irrig. Sci. 28:135–142.

    Ritter, W.F. and C.E. Beer. 1969. Yield reduction by controlled flooding of corn. Transactions of the ASAE 68-239. Logan, UT.

    Scott, H.D., J. DeAngulo, M.B. Daniels, and L.S. Wood. 1989. Flood duration effects on soybean growth and yield. Agron J. 81:631-636.

    Stevens, S.J., E.J. Stevens, K.W. Lee, A.D. Flowerday, and C.O. Gardner. 1986. Organogenesis of the staminate and pistillate inflorescences of pop and dent corns: relationship to leaf stages. Crop Sci. 26:712-718.

    Torbert, H.A., R.G. Hoeft, R.M. Vanden Heuval, R.L. Mulvaney, and S.E. Hollinger. 1993. Short-term excess water impact on corn yield and nitrogen recovery. J. Prod. Agric. 6:337-344.

    VanToai, T.T., J.E. Beurlein, A.F. Schmitthenner, and S.K. St. Martin. 1994. Genetic variability for flooding tolerance in soybeans. Crop Sci. 34:1112-1115.

  6. Double Crop Soybean Management Considerations for 2022

    Soybean field
    Author(s): Laura Lindsey

    Wheat harvest is just around the corner, and it’s time to consider double-crop soybean production management. For double-crop soybean to be successful, you need adequate time and moisture for the production of the soybean crop. In southern Ohio, double-crop soybean after wheat harvest is common. In central and northern Ohio, double-crop soybean after winter wheat depends on the wheat harvest date and soybean prices. With high soybean prices, we anticipate interest in double-crop soybean production in central and northern Ohio this year.

    Double-crop soybean management considerations.

    1. Soybean relative maturity. Relative maturity (RM) has little effect on yield when soybeans are planted during the first three weeks of May. However, the effect of RM can be larger for late plantings. When planting soybean late, the latest maturing variety that will reach physiological maturity before the first killing frost is recommended. This is to allow the soybean plants to grow vegetatively as long as possible to produce nodes where pods can form before vegetative growth is slowed due to flowering and pod formation.

    Table 1. Recommended relative maturity (RM) ranges for soybean varieties planted in June and July in northern, central, and southern Ohio.


    Planting Date

    Suitable RM

    Northern Ohio

    June 1-15


    June 15-30


    July 1-10


    Central Ohio

    June 1-15


    June 15-30


    July 1-10


    Southern Ohio

    June 1-15


    June 15-30


    July 1-10


    1. Row spacing. Double-crop soybeans should be produced in narrow rows- 7.5 or 15-inch row spacing. The later soybeans are planted, the greater the yield increase due to narrow rows. Soybeans grown in narrow rows produce more grain because they capture more sunlight energy, which drives photosynthesis.
    1. Seeding rate. The soybean plant population at harvest for mid-to-late June plantings should be between 130,000-150,000 plants/acre. The harvest population for early July plantings should be greater than 180,000 plants/acre. Harvest population is a function of seeding rate, quality of the planter operation, and seed germination percentage and depends on such things as soil moisture condition, seed-soil contact, and disease pressure.
  7. Double Crop Soybean Production in Northern Ohio

    Double cropped soybeans. Photo credit Matt Davis

    In northern Ohio, double-crop soybean production after wheat harvest needs to be carefully considered. There are both agronomic considerations (Do I have enough time and moisture to produce a soybean crop?) as well as economic considerations (Will my double-crop soybeans be profitable?). Profitability depends on soybean yield and price as well as the cost of inputs and field operations.

    At the Northwest Agricultural Research Station, we compared full-season soybean (soybean only), relay-intercropped soybean (soybean intercropped into wheat), and double-crop soybean following wheat harvest (Figure 1). Across the three years of the study, soybean yield was greatest for a full-season crop (average of 57 bu/acre) and lowest for a double-crop soybean (average of 20 bu/acre). Relay-intercropped soybean yield fell in the middle with an average yield of 34 bu/acre. In 2016, soybean yield as an intercrop and double-crop were extremely low (17 and 12 bu/acre, respectively) due to hot, dry conditions that year.)

    Figure 1. Soybean grain yield when grown as a full-season crop, a relay intercrop, and a double-crop at the Northwest Agricultural Research Station near Custar, Ohio. (Click here to read more about this study:

    While this assessment looks only at the soybean component, the profitability of the entire cropping year (wheat +soybean) may be desirable to consider when making double-cropping decisions. The profitability of these various production systems can be extremely variable depending on input, field operation, and commodity prices. We developed an excel-based calculator to help estimate profitability ( The calculator can be used to estimate a partial return of six different production systems:

    1. Winter wheat only
    2. Winter wheat + straw
    3. Full-season soybean (soybean only)
    4. Winter wheat (grown in 15-inch row width) with soybean intercropped
    5. Winter wheat followed by double-crop soybean
    6. Winter wheat + straw followed by double-crop soybean

    This calculator uses default values for crop prices, input prices, field operation costs, and projected crop yield from OSU Enterprise Budgets, OSU Custom Rate Survey, and OSU field research to compare the partial return of these six production systems. However, next to each default value, you can put in your production prices and costs to customize to your farming operation. Based on our calculator’s 2022 default values, the gross return, costs per acre, and partial returns are printed in the table below.

    Table 1. Partial return comparisons of six cropping systems. Default values are based on OSU Enterprise Budgets, OSU Custom Rate Survey, and OSU field research. Download the spreadsheet to edit with your values:








    Gross Return per acre


    Partial Return


    Wheat only (7.5-inch row width)





    Wheat only (7.5-inch row width) + straw





    Full season soybean





    Wheat (15-inch row width) with soy intercropped





    Wheat (7.5-inch row width) with soy double-crop





    Wheat (7.5-inch row width) with soy double-crop + straw




    The research used to produce this calculator tool was generously funded by Ohio Corn and Wheat.

  8. Lep Monitoring Network Update – BCW, AMW, and ECB Updates

    European Corn Borer larvae

    Moth trap updates for Ohio are reported below. All monitored pests remained below an average of 10 moths per county for the week of June 6 – 12. This will be our last update for black cutworm and true armyworm. We will continue to report on European corn borer catches and begin reporting on corn earworms starting next week. Western bean cutworm reporting will begin the week of June 27th.

    Black cutworm

    Black cutworm (BCW) numbers remain low in all monitoring counties (less than an average of 10 moths per trap) for the week of June 6th through June 12th (Figure 1). The highest weekly average was reported in Hardin County with an average of 8.7 moths.

    Black cutworm moth map

    June 6 – 12, 2022


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    Figure 1. Average black cutworm (BCW) moths were captured from June 6th through June 12th. The large number indicates the average moth count for the week and the small number in parentheses is the total traps set up in the county.

    True armyworm

    True armyworm (AMW) numbers also remain low in the monitoring counties (Figure 2). All counties reported an average of fewer than 5 moths for the week.

    True armyworm moth map

    June 6 - 12, 2022


Description automatically generated with medium confidence

    Figure 2. Average true armyworm (AMW) moths were captured from June 6th through June 12th. The large number indicates the average moth count for the week and the small number in parentheses is the total traps set up in the county.

    European corn borer

    We are in our fourth week of monitoring for the European corn borer (ECB), which continues to result in low trap numbers for all monitoring counties (Figure 3). Currently, Fulton and Hardin counties are the only counties reporting ECB moths. All counties reported less than an average of 2 moths per trap.

    European Corn Borer moth map

    June 6 - 12, 2022


Description automatically generated

    Figure 3. Average European corn borer (ECB) moths were captured from June 6th to June 12th. The first number indicates the average ECB-IA followed by a comma and then the average ECB-NY moth count for the week. The small number in parentheses is the total traps for each species set in each county.

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.


Alan Leininger (Educator, Agriculture and Natural Resources)
Alyssa Essman (State Specialist, Weed Science)
Amanda Douridas, CCA (Educator, Agriculture and Natural Resources)
Amber Emmons, CCA (Water Quality Extension Associate)
Andrew Holden (Resigned Educator, Agriculture and Natural Resources)
Barry Ward (Program Leader)
Beth Scheckelhoff (Educator, Agriculture and Natural Resources)
Carrie Brown (Educator, Agriculture and Natural Resources)
Chris Zoller (Educator, Agriculture and Natural Resources)
Clifton Martin, CCA (Educator, Agriculture and Natural Resources)
Clint Schroeder (Program Manager)
Curtis Young, CCA (Educator, Agriculture and Natural Resources)
Daniel Lima (Educator, Agriculture and Natural Resources)
Dean Kreager (Educator, Agriculture and Natural Resources)
Gigi Neal (Educator, Agriculture and Natural Resources)
Glen Arnold, CCA (Field Specialist, Manure Nutrient Management )
Grant Davis, CCA (Educator, Agriculture and Natural Resources)
Horacio Lopez-Nicora (State Specialist, Soybean Pathology)
James Morris (Educator, Agriculture and Natural Resources)
Jason Hartschuh, CCA (Field Specialist, Dairy & Precision Livestock)
John Barker (Educator, Agriculture and Natural Resources)
Kelley Tilmon (State Specialist, Field Crop Entomology)
Ken Ford (Educator, Agriculture and Natural Resources)
Les Ober, CCA (Educator, Agriculture and Natural Resources)
Mark Badertscher (Educator, Agriculture and Natural Resources)
Mike Estadt (Educator, Agriculture and Natural Resources)
Nick Eckel (Educator, Agriculture and Natural Resources)
Osler Ortez (State Specialist, Corn & Emerging Crops)
Pierce Paul (State Specialist, Corn and Wheat Diseases)
Richard Purdin (Educator, Agriculture and Natural Resources)
Stephanie Karhoff, CCA (Field Specialist, Agronomic Systems)
Taylor Dill (Graduate Student)
Ted Wiseman (Educator, Agriculture and Natural Resources)
Tony Nye (Educator, Agriculture and Natural Resources)
Trevor Corboy (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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