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C.O.R.N. Newsletter: 2018-18

  1. It’s probably not Frogeye Leafspot and no Brown Spot IS NOT an economically important disease

    Author(s): Anne Dorrance

    As farmers and consultants have been out checking their soybean stands, they are finding spots on the leaves.  The most common spotting on the unifoliates and first leaves is caused by Septoria glycines.  This is a fungus that overwinters on the previous soybean crop residue and in modern cultivars it is limited to the lower canopy.  We’ve done extensive studies on this disease over the past decade and I have yet to attribute an economic value in managing this.  We did this one experiment where put chlorothalonil on every week (not a legal application but for research purposes only) and could only measure a 3 to 4 bu increase when the soybean plants were totally clean of this disease.  Secondly, applications of herbicide plus fungicide did not manage this disease throughout the season nor do the R3 applications.  Septoria brown Spot- fungus survives on old soybean residue and is splashed onto lower leavesAt todays’ fungicide application costs and soybean prices, this is a hard one to even break even on.

    The one disease we have gotten substantial response to fungicide applications, is with frogeye leaf spot.  There are a few high yielding soybean cultivars that are very susceptible to this disease.  Yield losses of 8 to 35 bushels have been recorded.  The fungus that causes this disease can overwinter in Ohio, this was confirmed by studies in Illinois as well.  This fungus, Cercospora sojina, can also spread via large storm fronts, hurricanes from southern states where it can build up and the spores can be carried to new areas.  This happened in 2005 and again last summer based on my own scouting of test plots.  The symptoms are gray centers surrounded by a deep purple circle which forms the lesion.  Under high moisture conditions, Frogeye leaf spot: Early symptoms on new leavesthe spores of the fungus will form in the lesion on the underside of the leaves, actually look like whiskers.  There are a few herbicides, adjuvants, foam markers that under the right conditions will cause similar looking symptoms.  The easiest way to check is to place leaves with these symptoms in a plastic bag and see if they form the whiskers – or spores overnight.  These bags just need humidity – not a lot of free water.  Also note, this fungus will infect new leaves and if it is established with every rain event there will be continual infections of the new foliage. 

    To manage this disease, foliar applications at R3 have been very good in Ohio at managing this pathogen.  One note is that we have documented that strobilurin resistance is here in Ohio, so if you have any questions please send us these leaves, we do have time to test the fungicide sensitivity before you will need to spray.

  2. Manure Science Review - Wednesday, July 25

    Author(s): Mark Badertscher

    The 2018 Ohio State University Manure Science Review is scheduled for Wednesday, July 25 at the Watkins farm located at 18361 Township Road 90, Forest, OH 45843 in Hardin County.  The program will begin at 8:45 am, while registration, coffee and donuts will be offered in the morning starting at 8:15 am before the field day kicks off with the afternoon activities ending by 3:30 pm.

    The morning educational sessions in the main tent will focus on Waterhemp and Other Weed Seeds in Manure, Avoiding Manure Spills, Manure Application: Rules and Liability, Reducing Phosphorus Runoff, Regulations Update, and Valuing Manure.  There will be indoor demonstrations of Rainwater/Runoff Simulation and Cover Crops, OnMRK nutrient record keeping app, Ohio Farm Bureau Federation Demonstration Farms, and exhibitor introductions with displays.

    Following lunch, afternoon field demonstrations will include Preferential flow, Manure spreader calibration, Soil health: #SoilYourUndies, Shallow tillage for manure application, Seeding cover crops with a converted Highboy, Side dressing corn with manure, Center pivot irrigation, and Mortality composting.

    Continuing education units (CEU’s) are available for Certified Crop Adviser (CCA), ODA Certified Livestock Manager (CLM), ODA Fertilizer Recertification, Pennsylvania Manure Hauler/Broker, and Indiana Office of State Chemist (Cat 1, 14 and RT).

    Registration is $25 per person if completed by July 16 and $30 per person if completed after July 16.  Breakfast (coffee and donuts) and lunch is included with the registration fee.  The online form with additional information can be found at https://ocamm.osu.edu.  The flyer for this year’s Manure Science Review is at https://ocamm.osu.edu/sites/ocamm/files/imce/Events/MSR_2018_FLYER.pdf.  The online registration direct link is http://go.osu.edu/msr2018.

  3. New Episodes of the Agronomy and Farm Management Podcast

    TPodcastwo new episodes of the Agronomy and Farm Management podcast are available this month. In Episode 3, released June 13th , Dr. Mark Loux provides advice for managing some of Ohio’s toughest weeds! Episode 4, coming June 27th will help prepare you for disease scouting with Drs. Pierce Paul and Anne Dorrance sharing tips for identifying and managing common diseases of corn, wheat, and soybeans. Listen now at go.osu.edu/iTunesAFM or go.osu.edu/StitcherAFM. Be sure to subscribe so you don’t miss out on valuable information about what’s happening in the field and farm office!

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.

Contributors

Andy Michel (State Specialist, Entomology)
Anne Dorrance (State Specialist, Soybean Diseases)
Bruce Clevenger, CCA (Field Specialist, Farm Management)
Elizabeth Hawkins (Field Specialist, Agronomic Systems)
Garth Ruff (Educator, Agriculture and Natural Resources)
Glen Arnold, CCA (Field Specialist, Manure Nutrient Management )
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 Gastier, CCA (Educator, Agriculture and Natural Resources)
Peter Thomison (State Specialist, Corn Production)
Pierce Paul (State Specialist, Corn and Wheat Diseases)
Sarah Noggle (Educator, Agriculture and Natural Resources)
Wayne Dellinger, CCA (Educator, Agriculture and Natural Resources)

Disclaimer

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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