Corn Yield Response to Foliar Fungicides in Dry Conditions

Rationale and Objective

  • The potential for foliar fungicide treatments to be economically beneficial in protecting corn yield under moderate to high foliar disease pressure is well documented.
  • Recent claims have also indicated possible plant health and drought tolerance benefits associated with strobilurin fungicide treatments even in the absence of significant disease pressure.
  • Disease pressure is generally lower under drought conditions, as development and spread of several common foliar diseases is favored by moisture and humidity.
  • The abnormally dry conditions experienced in IA and MO during the 2011 and 2012 growing seasons allowed evaluation of fungicide performance with low disease pressure.

Study Description

Plot Layout:    Field-length strips with strobilurin fungicides applied in strips perpendicular to the rows
Locations:    43 locations in IA and MO in 2011-2012
Hybrids:    4 per location, 34 total
  • Plots were established  according to standard C-Pro protocol of 4 hybrids planted at 4 populations per location.
  • Yield monitor data from these plots were analyzed in Pioneer FIT Studio® to remove common sources of yield monitor error. Fifty-foot buffer areas were removed from the plots to account for potential drift from fungicide treatments in the checks.


  • The average yield response to foliar fungicides in strip trials conducted in 2011 and 2012 was well below the average response observed in a survey of IA and MO on-farm trials conducted between 2007 and 2010.
  • Yield results indicate that a foliar fungicide treatment is much less likely to be economically beneficial under low disease pressure associated with hot and dry conditions.
  • Previous research has shown that hybrid response to fungicides can vary widely based on genetic disease tolerance and disease pressure. 2011-2012 results showed that hybrid response can vary even when pressure is low.
  • Yield response to foliar fungicide treatment was not affected by plant population.
Chart: Average Corn Yield Response to Foliar Fungicides in On-Farm Trials
Chart: Average Yield Response of Four Pioneer Brand Hybrids to Foliar Fungicides in Western Iowa Trials
Chart: Fungicide-Treated and Non-Treated Corn Yield Response to Plant Populations

Management Suggestions

  • Target fungicide applications based on hybrid genetic disease tolerance and local crop conditions.
  • Consult with your local Pioneer sales professional for guidance on fungicide applications for the hybrids on your farm.
  • When evaluating hybrid performance, don't compare treated vs. untreated hybrids; the variability in hybrid responses could result in misleading information on the value of a hybrid.

2011-2012 data are based on average of all comparisons made in 43 locations through 2012. Multi-year and multi-location is a better predictor of future performance. Do not use these or any other data from a limited number of trials as a significant factor in product selection. Product responses are variable and subject to a variety of environmental, disease, and pest pressures. Individual results may vary. All products are trademarks of their manufacturers.

YGCB,HXX,LL,RR2 (Optimum® Intrasect® Xtra) – Contains the YieldGard® Corn Borer gene and the Herculex® XTRA genes for resistance to corn borer and corn rootworm.
Herculex® XTRA Insect Protection technology by Dow AgroSciences and Pioneer Hi-Bred. Herculex® and the HX logo are registered trademarks of Dow AgroSciences LLC.
YieldGard®, the YieldGard Corn Borer Design and Roundup Ready® are registered trademarks used under license from Monsanto Company.
Liberty®, LibertyLink® and the Water Droplet Design are trademarks of Bayer.
   AM1 - Optimum® AcreMax® 1 Insect Protection System with an integrated corn rootworm refuge solution includes HXX, LL, RR2. Optimum AcreMax 1 products contain the LibertyLink® gene and can be sprayed with Liberty® herbicide. The required corn borer refuge can be planted up to half a mile away.
HX1 – Contains the Herculex® I Insect Protection gene which provides protection against European corn borer, southwestern corn borer, black cutworm, fall armyworm, lesser corn stalk borer, southern corn stalk borer, and sugarcane borer; and suppresses corn earworm. Herculex® I Insect Protection technology by Dow AgroSciences and Pioneer Hi-Bred. Herculex® and the HX logo are registered trademarks of Dow AgroSciences LLC.