Effect of previous crop, tillage, field size, adjacent crop, and sampling direction on airborne propagules of Gibberella zeae/Fusarium graminearum, fusarium head blight severity, and deoxynivalenol accumulation in winter wheat

Abstract

The objective of this study was to determine the relative importance of previous and adjacent crop, tillage, field size, and sampling direction on the number of viable airborne propagules of Gibberella zea/Fusarium graminearum trapped at anthesis, fusarium head blight (FHB) index, percentage of seeds infected with F. graminearum, and deoxynivalenol (DON) accumulation in seed of winter wheat from commercial fields across southwestern Ontario. More viable airborne propagules of G. zeae/F. graminearum were trapped in wheat fields that were planted on corn or wheat stubble than in wheat fields in which previous crops were nonhosts. Previous crop, field size, and tillage interacted to affect the FHB index, DON accumulation, and percentage of seeds infected with F. graminearum; large fields where corn was planted one year previous to wheat with minimum or no tillage had the highest values. Adjacent crops (nonhost, corn, and wheat) affected the number of viable airborne propagules trapped, FHB index, and percentage of seeds infected with F. graminearum. Sampling direction (east–west) did not have a significant effect on any variable. The number of viable airborne propagules trapped at wheat anthesis was not predictive of FHB symptoms or DON accumulation in grain.

Keywords:

• Triticum aestivum
• Gibberella zeae
• agronomy
• crop history
• inoculum
• spore trapping