C.O.R.N. Newsletter: 2016-02

Northern corn leaf blight (NCLB), caused by the fungus Exserohilum turcicum, continues to increase in prevalence and severity in Ohio and across the corn belt. In 2015, it showed up much earlier than usual in several fields. Weather conditions and current production practices are clearly two of the primary reasons why we are seeing more and more NCLB. The widespread use of conservation tillage favors the survival of the fungus from one year to another, and increasingly rainy, humid conditions favor spore production, dissemination, and disease development. Infections typically occur when free water is present on the leaf surface for 6 to 18 hours and temperatures are between 65 and 80ºF. On susceptible hybrids, lesions develop within 7 to 12 days after infection, producing a new crop of spores that are easily splash- or wind-disseminated to new leaves and new plants.

Coupled with favorable weather, the use of susceptible hybrids and a possible shift in the race population of E. turcicum may also be responsible for the steady increase in NCLB. Several physiological races of the fungus are known to occur, including races 0, 1, 2, 12, 23, 23N and 123N. Of these, races 0 and 1 are the most frequently encountered. Two types of resistance are available to protect against these races: partial resistance (non-race specific), which is controlled my multiple genes and protects against all known races of the fungus, and race-specific resistant, which is controlled by single Ht genes and, as the name suggests, protects against specific races of the pathogen. Partial resistance is expressed as a reduction in the number and size of the lesions, and the amount of spores produced in these lesions, as well as an increase in the length of the incubation and latent periods (time taken for new lesions to develop and a new crop of spores to be produced).

Race-specific resistance is controlled by one or more of four Ht genes, Ht1, Ht2, Ht3, and HtN. Resistance conferred by Ht1, Ht2, and Ht3 is expressed as small chlorotic lesions with limited sporulation, whereas resistance conferred by HtN is manifested as fewer lesions and longer latent periods, similar to what is observed with partial resistance. Hybrids with Ht1 are susceptible (S) to races 1, 12 and 123N of the fungus, but resistant (R) to races 0, 2, 23, and 23N. In other words, race 1 of the fungus causes susceptible lesions (large necrotic cigar-shaped lesions) on hybrids with Ht1, but resistant-type reactions on hybrids with Ht2, Ht3 or HtN. Correspondingly, hybrids with Ht2 are resistant to races 0 and 1, but susceptible to races 2, 12, 23, 23N, and 123N (note that 2 is present in all of these race designations). On one extreme of the race x Ht gene interaction spectrum, hybrids with any of the four Ht genes will show a resistant response (small chlorotic lesions) to race 0, whereas on the other end of the spectrum, race 123N will produce a susceptible response on hybrids with any one or more of the four genes.

Field surveys conducted in Ohio during the 1980s and repeated again 20 years later (in 2003 and 2004) showed that races 0 and 1 of E. turcicum were the most prevalent in the state. Results from the 2003-2004 study also showed that 35% of the hybrids planted during that time had effective Ht resistance against race 1, while the majority, 65%, did not. In addition, the fact that typical cigar-shaped lesions (susceptible response) developed on all of the susceptible hybrids inoculated with race 1 suggested that the level of partial resistance in those hybrids was also low. So, if we assume that races 0 and 1 are still the most prevalent, the fact that we continue to see susceptible reactions on multiple hybrids at multiple locations across the state suggests that we are either planting hybrids without Ht genes (susceptible to races 0 and 1) or with Ht1 only (susceptible to race 1). However, without conducting another race survey and screening hybrids for resistance, we cannot entirely rule out the possibility of a race shift in the pathogen population. For instance, the widespread use of hybrids with the Ht2 or Ht3 genes (conferring resistance to races 0 and 1) could cause the frequency of races with virulence to these genes (i.e. capable of causing typical cigar-shaped lesions on Ht2 and Ht3 hybrids) to increase, rendering these hybrids susceptible to NCLB. This is called a race shift.

Until such time that we know which race(s) of the pathogen is (are) prevalent in your area:

1-    If the hybrid you planted in 2015 showed a susceptible reaction to NCLB, avoid planting that same hybrid in 2016 or subsequent years.

2-    Select hybrids with high levels of partial resistance. If we assume that races 0 and 1 are still predominant, hybrids with Ht1 (or any other Ht genes) will protect again race 0 while hybrids with Ht2 will be effective against both races. Ask your seed dealer for hybrids with high levels of partial resistance in combination with Ht1, Ht2 or other Ht genes.

3-    Fungicides are always a good option when susceptible hybrids are planted and conditions are favorable for NCLB, but are rarely needed when resistant hybrids are planted. Moreover, current grain prices are too low to justify fungicide applications.

Weather conditions and our production system will likely continue to favor NCLB (and similar diseases), so unless we manage this disease by selecting hybrids with good resistance, it is only time before we have a major epidemic and suffer significant yield losses. We dodged the bullet in 2015 because conditions became dry in most areas shortly after pollination, but we may not be as lucky in 2016. (Article PDF)            

Ohio State University Extension’s Agriculture and Natural Resources is hosting multiple meetings for those who need to meet state requirements for the Agricultural Fertilizer Applicator Certification program through the Ohio Department of Agriculture. A current listing of all educational programs offered by Ohio State University Extension can be found at http://pested.osu.edu/NutrientEducation/nutrienttraining.html

The certification process is a three step process that requires 1) attendance at an educational program sponsored by Ohio State University Extension, 2) completion of the certification application to ODA at the end of the educational meeting then 3) payment of a fee to ODA.

• For those who have a Pesticide Applicator License through the Ohio Department of Agriculture, there is no additional cost to obtain a fertilizer certification.  The expiration date for those holding both a Pesticide License and Fertilizer Applicator Certification will be the same year regardless of when the original fertilizer training is taken.  Re-certification for both will be based on the pesticide license cycle.
• Those without a current Pesticide Applicators License must attend a minimum 3 hour education program.  Once ODA receives verification of training ODA will send an invoice that needs to be completed and returned with a $30.00 fee.  Once ODA has payment, your certification card will be sent to you and is valid for three years.

The Certification is required for those who apply fertilizer on more than 50 acres of agricultural production grown primarily for sale. Fertilizer is defined as any substance containing nitrogen, phosphorus, potassium, or other plant nutrient in a dry or liquid formulation. All application types (broadcast, side dress, sub-surface, knifing, etc.) are included in the certification requirement. The only application placement exempted is start-up fertilizers that are applied through a planter. Certification is also required for any persons using manure from a permitted Confined Animal Feeding facility anywhere in Ohio. 

Anyone who has taken the training, applied to ODA and received their yellow “Agricultural Fertilizer Applicator Certification” card from ODA do not need any additional training until recertification is required. There are no “Agricultural Fertilizer Applicators Certifications” that expire before March 31, 2018. For recertification, 2 hours of training is required in the second or third year of the fertilizer certification cycle prior to the expiration date.

Agricultural Fertilizer Applicator Certification has record keeping requirements.  Fertilizer application records need to be documented within 24 hours of the application and kept for three years by the certified applicator. There is no standard recordkeeping format, but Ohio agricultural fertilizer records need to contain the following items:

• Name of the responsible agricultural fertilizer certificate holder (and name of applicator if different)
• Date of application (month, day, and year)
• Location or field identification number of fertilizer application area
• Rate of application (e.g., pounds of fertilizer per acre)
• Analysis of fertilizer applied (e.g., 11-52-0)
• Application method (soil injected, incorporated, surface-applied, etc.)
• Soil conditions at the time of application
• Temperature, precipitation, and other weather conditions at the time of application
• For surface applications only: was the ground frozen or snow-covered (yes/no)?
• Weather forecast for the day following the application

Applicators that are a current Certified Crop Adviser through the American Society of Agronomy or are Certified Livestock Managers through the Ohio Department of Agriculture are exempt from training and can apply directly to ODA for their Agricultural Fertilizer Applicator Certification. Contact ODA’s Pesticide and Fertilizer Section at (614) 728-6987 or Tollfree: 800-282-1955.

A large number of Ohio farmers hire machinery operations and other farm related work to be completed by others. This is often due to lack of proper equipment, lack of time or lack of expertise for a particular operation.  Many farm business owners do not own equipment for every possible job that they may encounter in the course of operating a farm and may, instead of purchasing the equipment needed, seek out someone with the proper tools necessary to complete the job. This farm work completed by others is often referred to as “custom farm work” or more simply “custom work”. A “custom rate” is the amount agreed upon by both parties to be paid by the custom work customer to the custom work provider.

Ohio State University Extension collects surveys and publishes survey results from the Ohio Farm Custom Survey every other year and we need your assistance in securing up-to-date information about farm custom work rates, machinery and building rental rates and hired labor costs in Ohio.

This year we are updating our published custom farm rates for Ohio. Extension Educators in Ohio will be disseminating surveys at select educational activities throughout the winter. There is also an online survey option that anyone can access. The online survey is available at: http://aede.osu.edu/customrate2016

We would ask that you respond even if you know only a few rates.  We want information on actual rates, either what you paid to hire custom work or what you charged if you perform custom work. Custom Rates should include all ownership costs of implement & tractor (if needed), operator labor, fuel and lube. If fuel is not included in your custom rate charge there is a place on the survey to indicate this.

You may access the survey at: http://aede.osu.edu/customrate2016

The deadline to complete the survey is March 31^st.

Looking for ways to maximize soybean yield and profit?  Attend one of the 2016 Ohio Intensive Soybean Management Workshops offered by The Ohio State University Extension.  This workshop will be hands on and open to producers and agricultural professionals.  The workshop is occurring at three locations:

1.       February 9, 2016:  Clinton County Extension Community Room, 111 S. Nelson Ave., Wilmington

2.       February 24, 2016:  Evolution Ag, 13275 U.S. Rt. 42, Plain City

3.       February 25, 2016:  Auglaize County Administration Building (downstairs), 209 S. Blackhoof, Wapakoneta

The workshop goes from 9:00 AM to 4:00 PM.  Topics and speakers include:

1.       Soybean Management – Row Width, Seeding Rates, and Yield Components by Dr. Laura Lindsey

2.       Soybean Fertility – Updating the Tri-State Fertility Recommendations by Dr. Steve Culman

3.       Soybean Insect Management – Late Season Pests and Seed Treatments by Dr. Andy Michel

4.       Soybean Disease – Seed Treatments and Soybean Cyst Nematode - Managing the Unseen by Dr. Anne Dorrance

5.       Local Update

The cost of the workshop is $70 per person.  Lunch will be provided.  The following publications will be provided to all participants:

1.       Ohio Agronomy Guide

2.       2016 Ohio, Indiana, and Illinois Weed Control Guide

3.       Corn, Soybean, Wheat, and Alfalfa Field Guide

4.       Profitable Soybean Disease Management Guide

5.       Control of Insect Pests of Field Crops

Space is limited for the workshop.  Advanced registration is due at least five days before each workshop.  To register for Clinton County workshop contact Tony Nye at nye.1@osu.edu or 937-382-0901, for Delaware County contact Robert Leeds at leeds.2@osu.edu or 740-833-2030, and for Auglaize County contact Jeff Stachler at Stachler.1@osu.edu or 419-739-6580.  Commercial and private Pesticide Credits and CCA and CEU credits will be available for the workshop.