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 100The Andersons Starts Venture Capital Subsidiary
January 26, 2015
The Andersons has established Maumee Ventures, a venture capital subsidiary designed to foster promising innovations that strategically align with the company’s core businesses. Read More
CropLife 100CHS Partners With Northern Partners Coop On Fertilizer Warehouse
January 21, 2015
In addition, the two companies will form a joint venture to build and operate a grain barge loading facility that will handle corn, soybeans and wheat for export through the CHS terminal at Myrtle Grove, LA. Read More
CropLife 100Wilbur-Ellis Move To Colorado Complete
January 20, 2015
Wilbur-Ellis Co. announces the opening of its new Agribusiness Division location in the Denver, CO, Metro Area. The new facility will host key personnel as the company shifts the base of its Agribusiness operations from California to Colorado. Read More
CropLife 100United Suppliers, McGregor Co., Five Others To Form Aligned Ag Distributors
January 20, 2015
These companies will continue to operate as independently owned and operated businesses, however, their crop protection divisions will now be formally aligned under the umbrella of Aligned Ag Distributors. Read More
CropLife 100Bozeman Named SEEDWAY Chief Operating Officer
January 16, 2015
He succeeds Donald Wertman, who will retire at the end of August 2015 after 40 years with the GROWMARK subsidiary. Read More
CropLife 100Wilbur-Ellis’ Craig Bair Honored For Safety Contributions To Ag Aviation
January 14, 2015
The William O. Marsh Safety Award recognizes significant achievements in safety, safety education or an outstanding operational safety program. Read More
Latest News
ManagementOABA Conference Set To Highlight Trends, Technology And…
January 29, 2015
The third annual Ohio AgriBusiness Association (OABA) Industry Conference is set to take place February 4-5. Read More
FertilizerThe Fertilizer Institute President Jahn Testifies Befor…
January 28, 2015
The committee hearing, "Freight Rail Transportation: Enhancing Safety, Efficiency, and Commerce," looked at challenges facing our nation's freight rail network created by higher demand, rules and regulations and infrastructure needs. Read More
HerbicidesPurdue University Acquires Technology For Herbicide Mol…
January 28, 2015
Protea's LAESI DP-1000 Instrument System will be used in Purdue's College of Agriculture, the Department of Botany and Plant Pathology, for the molecular imaging of herbicide active ingredients and other related compounds to optimize herbicide applications and improve weed management.  Read More
FertilizerH.J. Baker Hires New Crop Peformance Marketing Manager
January 27, 2015
As Marketing Manager for the Crop Performance division, Usman Khalid will work out of H.J. Baker’s global headquarters in Westport, CT, and will drive new initiatives for the division. Read More
CropLife 100The Andersons Starts Venture Capital Subsidiary
January 26, 2015
The Andersons has established Maumee Ventures, a venture capital subsidiary designed to foster promising innovations that strategically align with the company’s core businesses. Read More
Exclusive state-of-the art Stueve Construction designed “Vista View” Elevated Control Room.
Eric Sfiligoj2015 Agricultural Market Read: Mixed
January 26, 2015
The agricultural market could look radically different this year, profit-wise, depending upon which segment you do business in. Read More
Edward Chell Biosafe
Crop InputsBioSafe Systems Names Ed Chell California Territory Man…
January 26, 2015
BioSafe Systems has announced the recent addition of Ed Chell as California Territory Manager for the agrichemical division, supporting the crop protection, water treatment and food safety business segments. Read More
InsecticidesBayer CropScience Introduces Sivanto Insecticide
January 26, 2015
Sivanto precisely targets key damaging pests at multiple insect life stages to prevent damage to plants and help minimize the spread of diseases from insect carriers. Read More
ManagementRetail Collaboration, Communicating Agriculture’s Good …
January 23, 2015
Editors Paul Schrimpf and Eric Sfiligoj discuss the recent creation of Aligned Ag Distributors, and the US Farmers and Ranchers Read More
FertilizerOSU Expert: Toledo Water Crisis A Turning Point For Ohi…
January 23, 2015
The August 2014 water crisis in Toledo, OH, impacted Ohioans’ views of Lake Erie algae problems by increasing the attribution of blame of algae growth on agriculture. Read More
FertilizerH.J. Baker Launching TIGER XP
January 22, 2015
Tiger-Sul introduces this next generation sulphur-bentonite product with a proprietary activator – ensuring farmers have a well-balanced nutrient replacement program. Read More
Crop InputsH.J. Baker Expands China Sales Force
January 21, 2015
Global Agricultural firm H.J. Baker announced that sales veteran Shi Dongshen has joined their Shanghai office in China. This newest hire follows the recent opening of their Lianyungang Sulphur Bentonite Plant. Read More
CropLife 100CHS Partners With Northern Partners Coop On Fertilizer …
January 21, 2015
In addition, the two companies will form a joint venture to build and operate a grain barge loading facility that will handle corn, soybeans and wheat for export through the CHS terminal at Myrtle Grove, LA. Read More
Matt Hopkins5 Bold Predictions For Ag Retail In 2015
January 21, 2015
This past year was filled with ups and downs for the nation’s top ag retailers, but what will 2015 have in store? Read More
SoftwareDeere Launches App Center
January 20, 2015
The John Deere App Center provides users the ability to search and find apps most useful to their business or operations. Read More
Crop InputsNew Syngenta Herbicide Approved In Soybeans, Sunflowers
January 20, 2015
Syngenta will sell BroadAxe XC herbicide in 2015 for use on soybeans, sunflowers and dry peas Read More
CropLife 100Wilbur-Ellis Move To Colorado Complete
January 20, 2015
Wilbur-Ellis Co. announces the opening of its new Agribusiness Division location in the Denver, CO, Metro Area. The new facility will host key personnel as the company shifts the base of its Agribusiness operations from California to Colorado. Read More
Crop InputsNovozymes Sales Figures Up For 2014
January 20, 2015
Novozymes announces its sales growth in 2014 was in line with expectations as sales grew by 7% compared with 2013. Read More