Common Smut of Corn (Ustilago maydis)


Ontario is the province with the highest production of corn and common smut of corn is the most frequently occurring corn smut in Ontario. In severe years 25% of the corn in a field can have smut galls. Costs associated with smut related crop losses in Canada have not been estimated; however, in the USA, annual crop losses due to common smut have been estimated at 2% (Martinez-Espinoza et al. 2002). In 2006 the value of the corn crop in Ontario was CDN $847.3 million. At a 2% rate this would correspond to a loss of $16.9 million per year. If a given year was bad and the losses reached the OMAFRA stated estimates of 25%, the cost would be over $211 million. Therefore common smut of corn, caused by Ustilago maydis, is of significant economic concern.