Using fungicides to suppress Fusarium head scab in wheat
As wheat continues to develop heads across Michigan, growers will need to decide whether or not to apply a fungicide to combat Fusarium head scab.
Fusarium head blight, or head scab, continues to be Michigan’s most challenging wheat disease. Michigan State University Extension recommends growers consider using fungicides during wheat’s early flowering stage of development when weather conditions are conducive for its development.
The disease, in general, is favored by moderate temperatures of 56 to 86 degrees Fahrenheit and high relative humidity, particularly in excess of 90 percent, beginning and ending several days on either side of the early flowering period, which begins a few days after heading and continues for several days depending on air temperatures.
The Fusarium Risk Assessment Tool is available to give a daily risk assessment for specific locales. The model is correct about 75 percent of the time, but growers are also encouraged to consider their own experience. The other major consideration is the innate resistance individual varieties have to fend off the disease (see table).
The best fungicides against head scab include Prosaro and Caramba. These products usually reduce the severity of the disease and the associated mycotoxin (D.O.N. or vomitoxin) by half if applied correctly. To optimize the benefit of these fungicides, growers should treat two to seven days after the heads have begun to flower. An information piece, “Managing Fusarium head blight,” is available from MSU for more information.
The fungicide application targeting Fusarium head scab is also important in helping reduce yield losses from leaf diseases. Protection from these diseases, including leaf spots and leaf rust, during the flowering and grain fill periods often translates to several bushels of additional yield per acre.
|Relative susceptibility of winter wheat varieties to Fusarium head scab|
|Soft white winter wheat||Soft red winter wheat|
|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 suscetible|