By Jessica Ryan
When Fusarium head blight (FHB) threatens winter barley, the best time to apply a fungicide is about six days after full barley head emergence, according to a recent study published in Plant Disease.
FHB, also known as scab, is a fungal disease that attacks small grains, discoloring the heads and contaminating the grain with the mycotoxin deoxynivalenol (DON), a toxic compound also known as vomitoxin. For barley, the most common grain used to make malt for beer and spirits, even a small amount of DON can cause crops to be rejected by purchasers. The disease in malted barley kernels may lead to gushing, or the rapid and uncontrolled foaming of beer, making the crop unusable for beer production.
In a four-year study, researchers with the U.S. Department of Agriculture (USDA)'s Agricultural Research Service (ARS) and the University of Minnesota assessed three different fungicides for FHB reduction. The researchers evaluated the amount of DON present in mature winter barley heads following a fungicide application at one of three growth stages—half heading, full heading, and six days after full barley head emergence.