Using fungicides to suppress Fusarium head scab in wheat

Wheat fields are beginning to show signs of head emergence. This marks the time to consider applying fungicides to reduce the risk of head scab and leaf diseases.

May 23, 2018 - Author: Martin Nagelkirk, Michigan State University Extension, and Martin Chilvers, MSU Department of Plant, Soil and Microbial Sciences

Wheat head with flowers (anthers) mark the time for fungicide application. Photo by Martin Nagelkirk, MSU Extension.
Wheat head with flowers (anthers) mark the time for fungicide application. Photo by Martin Nagelkirk, MSU Extension.

This season, wheat disease levels have been relatively low due to the cool spring. However, now that temperatures have warmed and some areas have received lots of rain, it’s time to consider using a fungicide to curb fungal diseases common to wheat. A fungicide application during the flowering stage should target Fusarium head blight (or head scab) while recognizing that the treatment can be equally important in curbing foliar diseases that tend to develop on flag leaves during June.

Head scab is favored by moderate temperatures of 56 to 86 degrees Fahrenheit and high relative humidity, particularly in excess of 90 percent, around and during the flowering stage. Michigan State University Extension recommends utilizing the Fusarium Risk Assessment Tool. It provides a daily risk assessment for specific locales. The model is correct about 75 percent of the time, but growers should also rely on their own experience. Another consideration is the innate resistance individual varieties have to fend off the disease (see table).

Ground application is generally recommended for applying wheat fungicides. However, aerial application of fungicides may be necessary where wet conditions prohibit ground rigs from operating. Aerial application may have reduced head deposition compared to ground rigs, but still can offer significant protection against head and leaf diseases.

The best fungicides for head scab include Prosaro and Caramba. These products usually reduce the severity of the disease and the associated mycotoxin (D.O.N. or vomitoxin) level by half if applied correctly. To optimize the benefit of these fungicides, treat two to seven days after the heads have begun to flower. An information piece from MSU, “Managing Fusarium head blight,” is available as a resource.

Relative susceptibility of winter wheat varieties to Fusarium head scab
Soft white winter wheat Soft red winter wheat
VarietyRank*VarietyRank*VarietyRank*VarietyRank*
 Ambassador Very suscetible  Pioneer 25R40 Susceptible  Branson Moderately suscetible  MCIA Roane Moderately suscetible
 Skeet Safety Very suscetible  Wellman 206 Susceptible  Red Devil Moderately suscetible  Pioneer 25R50 Moderately suscetible
 Jupiter Susceptible  Hopewell Susceptible  AgriMax 413 Moderately suscetible  Red Dragon Moderately resistant
 AC Mountain Susceptible  Shirley Susceptible  DynaGro  9223 Moderately suscetible  DF 112R Moderately resistant
 Aubrey Susceptible  DynaGro 9243 Susceptible  Pioneer 25R39 Moderately suscetible  Pioneer 25R25 Moderately resistant
 Pioneer 25W36 Susceptible  Pioneer 25R47 Susceptible  DF 105R Moderately suscetible  Agrimax 415 Moderately resistant
 E6012 Susceptible  Red Ruby Susceptible  Sienna Moderately suscetible  Steyer Hunker Moderately resistant
 Venus Susceptible  Pioneer 25R62 Susceptible  Rupp 907 Moderately suscetible  L334 Moderately resistant
 DynaGro 9242W Moderately suscetible  Whale Susceptible  Sunburst Moderately suscetible  Rupp 972 Moderately resistant
 Pioneer 25W43 Moderately suscetible  DF 109R Susceptible  DynaGro 9171 Moderately suscetible   
 Syngenta 901 Moderately suscetible  Agrimax 438 Susceptible  AgriMax 444 Moderately suscetible
 Pioneer 25W31 Moderately suscetible  DF 045 Susceptible  DynaGro  9053 Moderately suscetible
 DynaGro 9353W  Moderately suscetible   SC1342 Susceptible  DynaGro 9042 Moderately suscetible
 DynaGro 9522 Susceptible  Wellman 123 Moderately susceptible

Tags: agriculture, field crops, msu extension, pest management, wheat


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