C.O.R.N. Newsletter: 2014-39

  1. Cold Weather and Fall Herbicides - to spray or not to spray

    Author(s): Mark Loux

    It’s always amazing to see apparently still thriving winter annual weeds underneath the snow or following some really cold weather.  Even the dandelions in the lawn appeared healthy yesterday, although they can be one of the first weeds to turn purple following really cold weather.  Their healthy appearance and lack of symptomology is actually somewhat disturbing since I treated them just prior to the recent deep freeze and had higher expectations.  Our best advice at this point on fall spraying is that once fields dry or freeze up enough to allow traffic again, there is still considerable benefit to applying herbicides for control of marestail and other weeds that persist through winter.  We expect the rate of herbicide activity to slow considerably compared with application a month ago when it was warm.  We probably have not applied herbicides following a period of weather exactly like the one we just experienced, but we have in the past applied into late December during or following cold weather, and the herbicides still seem to eventually work.  Keep in mind that not treating fields with a history of marestail problems this fall can make for a more challenging situation next spring, and more variability in control.  This can be adjusted for by using a more aggressive combination of burndown herbicides next spring, or applying earlier in spring and beefing up the residual herbicide component, or using two spring preplant treatments (early and at plant).  The goal of fall treatments is to ensure that the spring herbicide program has to address only small plants that start emerging in late spring, which allows more flexibility in herbicide choice and application timing.

  2. 2014 Ohio Soybean Performance Trials Available

    Author(s): Laura Lindsey

    The purpose of the Ohio Soybean Performance Trials is to evaluate soybean varieties for yield and other agronomic characteristics. This evaluation gives soybean producers comparative information for selecting the best varieties for their unique production systems.

    Head-to-Head Comparisons of Conventional, Liberty Link, and Roundup Ready (New for 2014).  Varieties were grouped, tested, and analyzed by maturity (early and late).  Conventional, Liberty Link, and Roundup Ready varieties were tested together and sprayed with conventional herbicides to allow for head-to-head comparisons.  Conventional, Liberty Link, and Roundup Ready entries are statistically comparable within a maturity range (early or late).

    A pdf of the 2014 Ohio Soybean Performance Trials can be found here:http://stepupsoy.osu.edu/news/2014-ohio-soybean-performance-trials

    Sortable data will be available soon at: http://hostedweb.cfaes.ohio-state.edu/perf/

  3. Temperature Management in On-farm Grain Bins

    There are recommended targets for percent grain moisture and grain temperature for winter grain bin storage.  Those recommended targets are listed in the following tables (Tables 1. and 2.).

    Table 1. Recommended grain moisture content for safe storage.*


    Moisture Content % Wet Basis**

    Storage Period




















    **Poor quality grain (broken, immature, pest damaged) should be held at 1% less moisture content than sound, high quality grain.

    Table 2. Recommended grain temperatures for safe storage.*


    Temperature (degrees F)











    ***Be careful not to freeze grain of higher moisture contents.

    *Source: University of Tennessee publication PB1724, "Maintaining Quality in On-farm Stored Grain."

    Targeted percent grain moisture contents should be attained through a combination of one or several of the following: natural field maturation and drying, grain dryer, and bin drying using aeration fans.  The higher the percent moisture content of the grain coming out of the field, the greater the necessity to use heat producing dryer systems.   After grain is dried to an acceptable percent grain moisture content, it  needs to be cooled to the appropriate temperature for storage.  Aeration fans should be run shortly after the grain is removed from the dryer (after a steeping period of 4-6 hours or more) to begin cooling the grain.  Grain should be cooled in steps to the desired overwintering temperature.  Thereafter, aeration fans should be run when outdoor temperatures are 10-15 degrees F lower than the grain temperature. 

    Aeration fan timing depends largely on the airflow (cubic feet per minute (cfm) per bushel) produced by the aeration fan(s) (see Table 3.).  It is recommended that air be pushed from the bottom to the top of the grain and the temperature of the grain be monitored in the headspace area to determine when the cooling/warming front reaches the top of the grain.  Once  desired grain temperature has been reached,  temperature should remain fairly stable in the grain mass because grain is an excellent insulator as long as there are no air movements through the grain mass.  Thus, after each aeration cycle is complete, the aeration fan should be blocked off to prevent unwanted air flows.

    Table 3.  Estimated aeration cooling and warming cycles (hours).*


    Aeration Cycles (hours)

    Airflow cfm/bushel
























    *Source: University of Tennessee publication PB1724, "Maintaining Quality in On-farm Stored Grain."

    Grain management with fluctuating temperature, begins with checking the current temperature of the grain mass.  If the temperature is between the 30-40 degree F range, shut down the aeration fans, block off the opening of the aeration fan and monitor the condition of the grain regularly through the rest of the winter until the grain is moved to sell.  If the temperature is not yet in the range, continue running the fans to bring temperature down to the desired range.

    Other tips for managing stored grain include:

    1.  Be sure grain is level in the bin head space to assure even flow through the entire grain mass.  Peaked grain in the middle of the bin is usually problematic.

    2.  Do not over-fill bins.  Access to the head space area is nearly impossible when a bin is over-filled.

    3.  Be safe in working in and around grain bins.  Work in teams, have safety plans, use lock-out to prevent augers from being started when one is working inside of a bin, and never enter a bin that is being loaded or unloaded.

    4.  Monitor your grain through the winter on regular basis.

  4. Winter Weather Outlook


    November will go down as a top 10 coldest November most likely with drier than normal precipitation and snowier than normal.

    If you look at the 10 coldest Novembers, the December to February period that follows is usually near normal temperatures and slightly wetter than normal precipitation but with a lot of changes and extreme within that period.

    The big high pressure in Alaska that drove cold air into the U.S. is forecast to breakdown and be replaced by more typical low pressure. This will allow for a more westerly flow pattern into a good part of December meaning temperatures will be near to slightly above normal the next 3-4 weeks. At the same time, the dry northwest flow will be replaced by a more active pattern yield normal or slightly wetter than normal conditions in Ohio the next 3-4 weeks.

    The official winter outlook by NOAA/NWS/CPC calls for equal chances for above, normal or below normal temperatures and slightly below normal precipitation.

    In the shorter-range, expect colder than normal weather to return this week with limited precipitation except near Lake Erie. However, by the end of Thanksgiving weekend into the start of December, it will turn much warmer than normal with wetter weather moving in. High temperatures in the first several days of December will reach into the 50s with some 60s even possible.

    After a drier finish to November the first week of November will turn wetter. For the latest 16-day average rainfall outlook go to the National Weather Service Ohio River Forecast Center link at:

    Normal rainfall is just over 1.5 inches for the 16-day period. For the latest NOAA/NWS U.S. climate model monthly temperature outlooks go to:

    For the latest NOAA/NWS U.S. climate model monthly precipitation outlooks go to:http://www.cpc.ncep.noaa.gov/products/people/wwang/cfsv2fcst/htmls/usPrece3Mon.html

  5. Cold Spring Rains Brought Perfect Conditions for Pythium in Ohio and a Few More Surprises.

    Author(s): Anne Dorrance

    From many of the samples we recovered both Pythium spp. and Fusarium spp..  Both are well-known seedling pathogens.  Our next step was to examine what the Pythium spp. were and then to determine if these were sensitive to metalaxyl.  In approximately 60% of the locations we were able to obtain a good quality sequence and a metalaxyl test for 28 isolates.

    From many of the samples we recovered both Pythium spp. and Fusarium spp..  Both are well-known seedling pathogens.  Our next step was to examine what the Pythium spp. were and then to determine if these were sensitive to metalaxyl.  In approximately 60% of the locations we were able to obtain a good quality sequence and a metalaxyl test for 28 isolates.


    We found a great diversity of Pythium spp., all have been reported previously as pathogens of soybean or corn.  Many have been found in Ohio in previous surveys.  The bottom line is that it was not the same one in each field, and where we were able to recover more than one isolate from a field – they were different species.  Again, this confirms our earlier reports that this is a very diverse group of pathogens in Ohio that are capable of causing widespread stand loss.

    Table 1.  Summary of Pythium spp. recovered from symptomatic soybean seedlings collected in Ohio during the spring of 2014.

    Pythium spp.

    Number of locations

    Insensitive to metalaxyl

    Sensitive to metalaxyl





























    ultimum var ultimum












    *2 isolates from one location, one grew at 100 ppm, the other no.

    Conclusion.  Clearly the seed treatments did not hold up in this scenario.  Seed treatments with only one active ingredient for Pythium spp. will not provide protection for the wide range of diversity that is now contributing to this disease complex.

    For the 2015 season, for those fields with a history of replant and stand establishment issues should focus on seed treatment that has a wide combination of active ingredients. 

    Other contributing others included:  Clifton Martin, Chrissy Balk, and Damitha Wickramasinghe

  6. So you want to be a CCA

    The next North American Certified Crop Adviser Exam Date is February 6, 2015. The registration period closes on December 5, 2014.  

    Keep in mind, to become eligible for the CCA certification, you must take and pass boththe North American and the local (state/province) board exams. For us in Ohio, Indiana and Illinois that is the Tri-State exam – a group of educators and practicing CCAs from each state gather regularly to update and verify the exam. 

    For more information and to register, see this website:https://www.certifiedcropadviser.org/exams/registration. The cost for the International (for us North American) exam is $175 and the Tri-state exam is $50. You must be registered to take either exam. The Ohio site for the February 6th CCA exam is Marysville at the Union County Services Building on south London Avenue (SR 38).

     What to study: The exam follows the performance objectives of the Tri-State Exam committee: https://www.certifiedcropadviser.org/files/certifiedcropadviser/obj-tristate.pdf. Our suggested list of study materials includes the Ohio Agronomy Guide, the Tri-State Fertilizer Recommendations, the Ohio & Indiana Weed Control Guide, the Corn, Soybean, Wheat & Alfalfa Field Guide, Modern Corn & Soybean Production to name a few items. Also available is a study guide for the International Exam from IPNI:http://www.ipni.net/article/IPNI-3350

    The CCA program is truly international with CCAs in the US, Canada, Mexico and India. This program started 20 years ago from industry and university interest in documenting the continuing education that crop advisers and agronomists need to best provide advice to their farmer clients.

     After the exam is passed,

    o   The candidate documents their education and experience

    o   And provide references from their employer and clients.

    o   The next item to becoming a CCA is to sign the Code of Ethics. 

     Once a CCA, then we are required to participate in 40 hours of continuing education every two years.

    For more information, see: www.certifiedcropadviser.org.  

    The OSU Agronomic Crops Team offers a two-day exam preparation class January 14 & 15, 2015 in Sidney Ohio. Information is available on the Agronomic Crops Calendar webpage: https://agcrops.osu.edu/calendar/certified-crop-adviser-cca-exam-training-session. The price for the program is $225; secure on line registration via credit card, debit card or check is available at:https://www.regonline.com/Register/Checkin.aspx?EventID=1646493

  7. Double Crop versus Modified Rely Intercrop Soybean Yields in 2014

    Modified Relay Intercropping (MRI) is the planting of soybeans into headed wheat that may occur up to 6 weeks or more prior to wheat harvest; whereas Double Cropping (DC) is the planting of soybeans after wheat harvest.    Vyn et al, found that relay intercropping of soybeans yielded better than double cropping of soybeans north of I - 70 in Indiana (http://www.agry.purdue.edu/staffbio/AY316.pdf).   

    There are pros and cons with each system.  In both systems, two crops, wheat and soybeans are harvested in the same growing season.  In 2014, MRI and DC systems were planted at two locations; one in central Ohio at South Charleston (SC) and another at Bucyrus in north central Ohio. 

     Average yields over soybean and wheat in the two systems may offer a general comparison.  

     MRI vs DC  Soybean Yields in 2014


     MRI 15 inch rows (SC)

    MRI Twin Rows (Bucyrus)

    DC (SC)

    DC (Bucyrus)

    Soybean Yields (bu/ac)






    35 bu/ac

    18 bu/ac

     MRI soybean yields were similar for the two sites in this trial (over all soybean plot yield averages (bu/ac) were  43 and 33 at SC and Bucyrus respectfully). Planting dates for DC soybeans were:  July 11 at SC and Bucyrus.  Rainfall from June 1 to August 31 was 9.9 inches at SC and 12.2 from 5/11 to 8/31 at Bucyrus. Stands were excellent at both locations; however soil types differed with SC being a Crosby and Bucyrus a Blount.  Yield differences might also be related to the length of the growing season.  Bucyrus DC soybeans had been killed by frost up to 10 days earlier than SC and were harvested 11/3, whereas SC soybeans were not harvested (not ready) until 11/11. 

    Interseeding  vs No interseeding  on  Wheat Yield 


     MRI 15 inch rows Wheat  (SC)**

    MRI  10 inch Wheat  - 3 year average (Bucyrus)*

     15 inch row Wheat   at (SC)**

    10 inch row wheat  – 3 years average  (Bucyrus)*

    Wheat  Yields (bu/ac)








    * 2011-2013 time period; ** 2014 

    There is a negative interseeding  effect  on wheat yield in the row spacing used above.  The effect will depend on many factors such as: when wheat was interseeded, equipment operation and set up and wheat row spacing.  In 2014 , a 7 bushel difference in wheat yield was observed in 15 inch rows .  In 10 inch rows, for 3 years at Bucyrus, there was a 2 bushel difference.   

    In summary, DC soybeans with a shorter growing season are at greater risk to adverse weather over rainfall and growing season length. However, DC will almost always be expected to have better wheat yields.  For more information on the Modified Relay Intercropping go to:  http://ohioline.osu.edu/agf-fact/0504.html

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.


Andy Michel (State Specialist, Entomology)
Eric Richer, CCA (Educator, Agriculture and Natural Resources)
Glen Arnold, CCA (Field Specialist, Manure Nutrient Management )
Greg LaBarge, CPAg/CCA (Field Specialist, Agronomic Systems)
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)


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.