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

Soybean Field
FungicidesGrowers Report Yield Boost, Extended Residual Disease Control From Trivapro Fungicide
January 9, 2017
With the new growing season around the corner, it’s time to start thinking about inputs for 2017. As growers weigh Read More
Monsanto Bioag logo
FungicidesIsagro USA Named Exclusive Distributor For Taegro 2 Biofungicide In U.S., Canada
January 4, 2017
Isagro USA, Inc. has signed an agreement to exclusively distribute Taegro 2 Biofungicide in the U.S. and Canada. The BioAg Alliance Read More
Brown stem rot in soybeans
FungicidesTips For Managing 6 Serious Soybean Diseases
December 28, 2016
There’s no shortage of diseases waiting to descend on your soybean crop. No matter where you farm, managing disease requires Read More
FungicidesManaging Sudden Death Syndrome And Brown Stem Rot In Soybeans
December 28, 2016
Cool wet soils in spring can lead to increased chances for sudden death syndrome (SDS) or brown stem rot (BSR) Read More
Trending Articles
AgriSync
Matt Hopkins17 Agriculture Apps That Will Help You Farm Smarter In 2017
December 9, 2016
Ag professionals are working smarter, not harder, than ever before. Smart farming technologies have enabled them to reduce costs, maximize Read More
R4023 Sprayer, John Deere
CropLife 100Ag Retail Equipment Report: The Green Party Continues
December 7, 2016
In the annual race for sales in the ag retail equipment marketplace, the color schemes for participants are a little Read More
Mike Stern
Precision AgClimate Corp. CEO Talks Retailer Support For Digital Ag
December 1, 2016
CropLife Magazine’s sister publication, AgriBusiness Global, recently sat down with Mike Stern, CEO of The Climate Corp., following the Monsanto subsidiary’s Read More
Precision AgTrimble Debuts End-to-End FMIS Platform
November 28, 2016
October’s inaugural PrecisionAg Vision Conference left this author with many thoughts and things to ponder in the coming months. Probably Read More
CHS Primeland
CropLife 100The 2016 CropLife 100 Report: Reviewing The Many Bulls And Bears Impacting This Year’s Marketplace
November 28, 2016
For virtually all of 2016, the nation was wholly focused on the big Presidential election. Some folks aligned themselves with Read More
Monsanto sign
Crop InputsMissouri Governor Meets With Bayer CEO To Discuss Monsanto Merger
November 21, 2016
Missouri Gov. Jay Nixon visited Bayer AG global headquarters in Leverkusen, Germany, on November 18 to discuss the proposed Bayer-Monsanto Read More
Latest News
Young Corn Plants
ManagementTimac Agro USA Acquires Michigan Ag Retailer
January 20, 2017
Timac Agro USA, an agriculture supply company specializing in high-efficiency plant and animal nutrition products, has acquired St. Louis,MI-based A&E Ag, Read More
Soybean field
Crop InputsNufarm Teams Up With John Deere Financial
January 19, 2017
Nufarm and John Deere Financial have teamed up to help farmers grow a better tomorrow. This program helps make purchases Read More
Sonny Perdue
LegislationTrump Formally Picks Perdue As Agriculture Secretary
January 19, 2017
U.S. President-elect Donald Trump officially announced Sonny Perdue as his choice for secretary of agriculture on Thursday, selecting a former Read More
ManagementPresident Trump, Wisconsin Review, and a Dow-DuPont Upd…
January 18, 2017
Editors Paul Schrimpf and Eric Sfiligoj reflect on a new administration, a recent winter show, and crop protection company mergers. Read More
Industry NewsBayer, MS Technologies Get China Approval For Balance G…
January 18, 2017
MS Technologies and Bayer have received import approval from China for Balance GT soybeans. The new Balance GT Soybean Performance Read More
Werner Baumann, Bayer AG, and Hugh Grant, Monsanto
Industry NewsReport: Monsanto, Bayer CEOs Among Latest to Make Trump…
January 18, 2017
The chief executive officers of German chemical giant Bayer AG and U.S. seed behemoth Monsanto, Werner Baumann and Hugh Grant, Read More
Giant Ragweed
HerbicidesStudy: Focusing On Weed Seedbank Can Help Manage Herbic…
January 18, 2017
Researchers writing in the latest issue of the journal Weed Science provide important insights on the control of herbicide-resistant giant Read More
Management3 Financial Trends To Watch In Agriculture
January 17, 2017
I recently had the opportunity to attend a meeting of credit managers for Midwest ag supply and input companies, in part Read More
Andersons Retail Store
CropLife 100The Andersons To Close All Retail Stores; Shutdown Does…
January 16, 2017
In a stunning announcement to the Toledo area, The Andersons Inc. said on Sunday that it would close its two Read More
Trimble TMX-2050 In-Cab Display
Eric SfiligojPrecision To Lead Agriculture In 2017?
January 16, 2017
Another new year is upon us! And I’m certain I speak for many in the agricultural world when I say Read More
Corn
Eric SfiligojThe Mood From Madison? In A Holding Pattern
January 16, 2017
Last week, I had the chance to attend the annual Wisconsin AgriBusiness Classic show in Madison, WI. It’s been a Read More
Syngenta Sign
Crop InputsAccenture Helps Syngenta Transform Its Global Logistics
January 13, 2017
Syngenta, a leading agriculture company, has collaborated with Accenture to design and implement a new digital logistics operating model across Read More
Fall Creek Seth Harden The Nature Conservancy
StewardshipLocal Farmers’ Watershed Initiative: Continuous Improve…
January 13, 2017
The goal in the Big Pine Watershed Project is to more intentionally do what local farmers and responsible ag retailers Read More
HerbicidesEPA Expands Enlist Duo Herbicide Registration To 34 Sta…
January 13, 2017
The U.S. EPA has expanded the geography for application of Enlist Duo herbicide from 15 to 34 states. This means Read More
Olson Ag Enterprise
CropLife 100Wilbur-Ellis Acquires Nebraska Seed Retailer
January 13, 2017
Wilbur-Ellis’ Agribusiness, a recognized leader in precision agriculture technology and the distribution and marketing of plant protection, seed and nutritional Read More
ManagementDeere-Precision Planting Update and the Ag Secretary Wa…
January 12, 2017
Editors Paul Schrimpf and Eric Sfiligoj provide the latest on the court date for John Deere/Precision Planting and the quest Read More
Monsanto sign
Seed/BiotechMonsanto, NRGene Form Agreement For Big Data Genomic An…
January 12, 2017
Monsanto Co. and NRGene have announced that the companies have reached a non-exclusive, multi-year global licensing agreement on NRGene’s genome-analysis Read More
AGCO Custom applicator
SprayersAGCO, Asmark Institute To Offer Training For Beginning …
January 11, 2017
AGCO Corp. and the Asmark Institute are collaborating to offer a new training program dedicated to educating and developing custom Read More