Common bunt is one of the most destructive diseases of wheat. As the fungus grows in the plant, the wheat kernels are converted to bunt balls that, when crushed, release thousands of black spores. They smell of rotting fish, hence the name “stinking smut”. Because of effective chemical seed treatment, common bunt had become a forgotten disease—until its reemergence in European organic wheat.

“The legal requirement for organic seed has compounded the bunt problem in Europe. For many years, it was possible to use conventionally produced seed as long as the cultivars were not of transgenic origin and the seed had not been treated after harvest with synthetic fungicides. All of this changed with Commission Regulation (EC) No. 1452/2003, which stipulated that beginning January 2004, all plant materials used for organic agriculture must be produced under organic farming conditions.”

“In conventional agriculture, common bunt is often exclusively controlled with chemical seed treatments. … Now, more than half a century after common bunt was thought to be vanquished, it has re-emerged in organic wheat. … In the United Kingdom, organic seed lots are predominantly contaminated with common bunt spores.”

“Contamination of wheat with common bunt spores has resulted in considerable loss of yield and seed quality. … Given the epidemiology of the disease, it has the potential to cause economic devastation to low-input and organic farmers.”

Authors: J.B. Matanguihan, K.M. Murphy and S.S. Jones*
Affiliation: *Department of Crop and Soil Sciences, Washington State University
Title: Control of Common Bunt in Organic Wheat.
Publication: Plant Disease. 2011. 95(2):92-103.