Using Fungicides To Suppress Fusarium Head Scab In Wheat

Fusarium head scab continues to be Michigan’s most challenging wheat disease. Michigan State University Extension recommends growers consider the use of fungicides during wheat’s early flowering stage of development when weather conditions are conducive for Fusarium development and infection. A fact sheet titled “Managing Fusarium Head Blight” is available for learning more about the disease and the use of fungicides.

The disease, in general, is favored by moderate temperatures (56 to 86) and high relative humidity (particularly in excess of 90 percent) beginning and ending several days on either side of early flowering. The national Fusarium prediction model is available to give a daily risk assessment for specific locals. The model is correct about 75 percent of the time, so growers are also encouraged to consider their own experience and that of local consultants.

Fusarium risk assessment for Michigan. The model
represents more than a decade of model development
and testing by multiple universities.

The best fungicides for reducing Fusarium’s threat to grain quality are Prosaro and Caramba. However, even these products may only reduce the infection level by 40 percent and the associated mycotoxin (D.O.N.) by approximately less than 50 percent. To optimize the benefit of a fungicide treatment against Fusarium, growers should make sure to apply when wheat is in the early flowering stage – depending on air temperature, this is usually two to five days after half of the heads have fully emerged above the flag leaf collar.

The application timing of early flowering mostly targets Fusarium head scab. In practice, however, fungicide use at this time is equally important for the suppression of various foliar fungal diseases that invariably threaten yields. This often lends additional financial justification for the use of a fungicide.

source : msu.edu