Plan Foliar Application Now

Ag dealerships and cooperatives need to encourage growers to lock in their foliar fungicides now, says one Extension expert.

Greg Shaner, Purdue University Extension specialist, says your growers shouldn’t wait until the July to make their application decisions. Disease pressures on corn vary from year to year in Indiana so it’s difficult to determine what problems will develop this summer. However, Shaner offers tips on making educated guesses this spring about disease risk this summer that can apply across the country. Shaner’s tips are written for growers, but can apply to retailers as well.

There are three conditions that determine whether a disease will develop on corn (or on any other crop) — the susceptibility of the hybrid, the abundance and virulence of the pathogen, and weather.

  • Of these, the host side of the triangle is the one growers and their advisors know the most about in spring. Check the resistance ratings for important diseases in the hybrids your grower-customers plant to assess disease risk. (Granted, there is no industry standard for reporting resistance ratings. Take into account the grower’s field conditions and production practices.

 

  • It is also possible to make some educated guesses about the pathogen side of the triangle at this time. Except for the two rust fungi that infect corn, fungal pathogens survive locally. Many of these fungi survive in residue of plants they infected last summer. Although residue from last year’s corn crop has been dead for months, the pathogens in it are alive and well. As temperatures rise, these fungi produce spores on the residue. Wind will disperse spores from the residue and some will land on next summer’s corn to start a new disease cycle.

 

  • A downside of conservation tillage has been an increase in disease pressure. Leaving corn residue on the soil surface allows pathogens to survive in much greater number compared to the days when moldboard plowing was common. If corn is grown in rotation with soybeans, and the ground is worked enough to provide a clean seedbed for corn, then inoculum (spores of the fungal pathogens) won’t be abundant in that field. These clean fields aren’t without risk, however. Wind can carry spores from adjacent fields where corn residue is on the soil surface. Risk of disease is probably greater in a conservation tillage system or where corn is grown after corn. In these systems there may be corn residue in the cornfield itself. Other conditions being equal, disease is likely to get started earlier in a field where corn residue is present than in a clean field.

 

  • University trials are beginning to yield data on fungicide efficacy in hybrid corn. In five trials we conducted in Indiana last year we saw no statistically significant increase in yield as a result of fungicide application. This is not surprising because disease pressure was very light at all locations. In a summary of 89 university trials from the Atlantic Coast to the Great Plains, Headline fungicide applied at 6 fluid ounces per acre resulted in yield responses that ranged from a negative 18 bushels per acres (bu/A) to a positive 23 bu/A. The average yield response over all trials was 4.1 bu/A (Note: I single out Headline because it was included in all trials. Other fungicides were tested in some, but not all trials. Results for these were similar). In 54% of the trials the yield response was 5 bu/A or greater. For trials in which the hybrid was susceptible or moderately susceptible to gray leaf spot the average response to fungicide application was 6 bu/A. For trials in which the hybrid was moderately resistant or resistant to gray leaf spot, the average yield response to fungicide application was only 3 bu/A.

 

  • A grower who is considering an application of a foliar fungicide to corn should first determine the hybrid’s degree of resistance to gray leaf spot, northern corn leaf blight, anthracnose, and common rust. If the hybrid has poor resistance to any of these, that would be a reason to consider a fungicide. Second, the grower should assess inoculum pressure (the abundance of corn pathogens). Corn-after-corn or reduced tillage systems will probably result in more inoculum than rotation corn with some tillage prior to planting. High inoculum pressure would be another reason, along with a susceptible hybrid, to consider a fungicide.

 

  • The big uncertainty is weather. Even if a grower has a susceptible hybrid and abundant residue in the field or nearby, weather must be favorable for disease. The dry summer in much of Indiana last year prevented spore production and infection and we saw little leaf disease. It’s impossible to say now what the weather will be like next July and August (with apologies to the meteorologists). Assuming we don’t have a drought this year, a grower’s experience may indicate that some fields are more likely to have disease problems than others. Humidity is often higher and dew heavier and more persistent in bottomlands or fields that are bordered by woods compared to fields in wide-open spaces. Long dew periods and high humidity favor production of spores and give spores that land on corn leaves time to germinate, infect, and establish new infections.

Shaner encourages those using a fungicide to leave at least two, preferably three, untreated strips in a field. If application is by air, an accurate map that shows the location of the strips is needed to compare yield in the treated and untreated areas. He also notes that it is also a good idea to walk treated and untreated areas in late August to see if there are differences in leaf health, and in late September or October to check effects of treatment on stalk health.

(Source: Purdue University)
 

Leave a Reply

Fungicides Stories
FungicidesSudden Death Syndrome, Brown Stem Rot Reported In Indiana Soybeans
September 3, 2014
Farmers and retailers should be watching for symptoms of these two diseases over the next few weeks as they are best managed through preventative methods. Read More
FungicidesResearchers Target Soybean Disease With Genetic Resistance Study
August 6, 2014
University of Illinois researchers will share new information on controlling sudden death syndrome through genetic resistance at this year's Agronomy Day. Read More
Soybean field
FungicidesValent Launches New Seed Protection Fungicide For Soybeans
July 16, 2014
The INTEGO SUITE System contains the first new, novel seed protection fungicide chemistry registered in 30 years by the EPA for protection against Pythium and Phytophthora. Read More
FungicidesNew Players May Make Pest Headlines In Corn, Soybean
April 1, 2014
The usual insects and diseases took a bit of a break in 2013, but other culprits surfaced — and could return. Read More
Top 100 Articles
CropLife 100Pinnacle Agriculture Acquires Minnesota Retailer
April 14, 2015
Pinnacle Agriculture Holdings, LLC, ranked No. 6 on the CropLife 100,  has successfully acquired Liebl Ag, LLC in Ada, MN.  Read More
CropLife 100CHS, Aurora Cooperative Complete Fertilizer Storage, Grain Shuttle Loading Facility
April 13, 2015
CHS Inc., the nation’s leading cooperative and ranked No. 5 on the CropLife 100, and Aurora Cooperative (ranked No. 21) Read More
CropLife 100GROWMARK Acquires Missouri Refined Fuels Terminal
April 2, 2015
Bloomington, IL-based GROWMARK and Magellan Pipeline Co. have entered into an agreement in which GROWMARK will acquire the refined fuels Read More
CropLife 100Wilbur-Ellis Acquires South Dakota Retailer
April 2, 2015
Wilbur-Ellis Co.’s Agribusiness Division, a recognized leader in precision agriculture technology and the distribution and marketing of plant protection, seed Read More
CropLife 100The McGregor Co. Closes Smith-Kem Acquisition
April 2, 2015
The McGregor Co. — ranked No. 16 on the CropLife 100 list of largest U.S. ag retailers — has completed Read More
CropLife 100BRANDT Commemorates National Ag Day
March 20, 2015
The Illinois agriculture community gathered at BRANDT global headquarters on March 18 to celebrate National Ag Day behind this year's theme Sustaining Future Generations. Read More
Latest News
StewardshipTFI Announces Renewed Financial Commitment To Fertilize…
April 24, 2015
Today, The Fertilizer Institute’s (TFI) President Chris Jahn announced that TFI and over 100 partners will more than double existing Read More
Industry NewsMACA Names New Ambassador Coordinator
April 23, 2015
The Mid America CropLife Association (MACA) has named Michelle Kilper as its new Ambassador Coordinator. Michelle is a graduate of Read More
ManagementAg Retailer’s Role In Local Policy Making; Raising The …
April 23, 2015
CropLife’s Paul Schrimpf and Eric Sfiligoj review their recent travels, precision ag efforts in Washington, DC, and the role of Read More
TMX-2050 In-Cab Display Launch Run Screen
Precision AgIn-Cab Computing 2015: Connectivity, Compatibility Take…
April 23, 2015
In terms of in-cab computing solutions for the agriculture market, companies like Case IH, Topcon, Trimble, John Deere and Raven Read More
USDA
StewardshipUSDA Outlines Building Blocks For Climate Smart Agricul…
April 23, 2015
Today, the USDA has announced a comprehensive and detailed approach to support farmers, ranchers, and forest land owners in their Read More
Industry NewsArysta LifeScience Welcomes New Territory Sales Manager
April 23, 2015
Arysta LifeScience North America recently announced the addition of Kaitlyn Acaster to the Canadian sales team. Acaster will fill the Read More
Crop InputsMarrone Bio Innovations Opens New Research Greenhouse
April 23, 2015
Marrone Bio Innovations, Inc. (MBI), a leading provider of bio-based pest management and plant health products for the agriculture, turf Read More
Crop InputsDuPont Acquires Taxon Biosciences
April 23, 2015
DuPont has agreed to acquire Taxon Biosciences, Inc., a leading microbiome discovery company. This acquisition will build on DuPont’s in-house capabilities Read More
Farmer on tablet
ManagementStudy: Consumers Don’t Care If U.S. Farmers Feed …
April 23, 2015
“We’re feeding the world” is a mantra often used by those involved in farming and food to build support for Read More
Industry NewsCorporate Responsibility Magazine Names Monsanto One Of…
April 22, 2015
Corporate Responsibility Magazine (CR Magazine) named Monsanto Co. to its 100 Best Corporate Citizens List for 2015. This is the Read More
FertilizerSpring Nitrogen Management: Form And Timing
April 22, 2015
Most corn producers have planned their spring nitrogen program for 2015, and many have already started to implement their program. Read More
FMC 3Rive 3D
Industry NewsFMC Corp. Completes Acquisition Of Cheminova
April 22, 2015
FMC Corp. has completed the closing of its acquisition of Cheminova A/S, a multinational crop protection company based in Denmark Read More
SoftwareSyngenta Expands AgriEdge Excelsior Nationwide For 2015
April 22, 2015
Growers across the country can now take the guesswork out of improving their farm’s production, land value, farm stewardship and Read More
Cornfield near Sioux City Iowa
HerbicidesU.S. Regulators May Start Testing Food For Glyphosate R…
April 21, 2015
U.S. regulators may start testing food products for residues of the world’s most widely used herbicide, EPA told Reuters’ Carey Read More
FungicidesBRANDT Adds Zonix Biofungicide To Portfolio
April 21, 2015
BRANDT has added Zonix biofungicide to its rapidly expanding line of organic and sustainable products. Zonix is a contact fungicide that Read More
ManagementMissouri Experts: Spring Planting Slow Start Won’…
April 20, 2015
In the first of the agronomy teleconferences with Extension specialists, University of Missouri Extension climatologist Pat Guinan said the slow Read More
Carl Casale of CHS
Industry NewsCooperative CHS Reports Net Income Of $471.5 Million Fo…
April 20, 2015
CHS Inc., the nation’s leading farmer-owned cooperative and a global energy, grains and foods company, has announced company net income Read More
Industry NewsCHS Insurance Names New Director Of Sales
April 17, 2015
Bryan Lewis has been named director of sales for CHS Insurance, the nation’s largest agribusiness insurance broker and full-service insurance Read More