Crop production factors associated with fusarium head blight in spring wheat in eastern Saskatchewan

Fusarium head blight (FHB) has been increasing in western regions of the Canadian Prairies. The objective of this 4-yr study was to identify crop production factors (CPF), associated with FHB development in spring wheat (Triticum aestivum L.). From 1999 to 2002, 659 crops were sampled in eastern Saskatchewan for FHB levels, and information gathered on agronomic practices used on these fields. In 2000 and 2001, percent Fusarium-damaged kernels (FDK) was also determined. Differences in the FHB index among years indicated that environment was the most important factor affecting disease development. The effects of CPFs on FHB were lower in years with high (2001) and low (1999 and 2002) disease pressure, compared with a year with moderate (2000) disease pressure. Previous application of glyphosate [N-(phosphonomethyl)glycine] formulations (GF) within tillage system, tillage system, previously grown crop, and cultivar susceptibility were the only CPFs that affected FHB. GF application in the previous 18 mo within tillage system was significantly associated with higher FHB levels every year; it was the only CPF in 1999, and one of two CPFs in 2002, that affected FHB, suggesting that its effect was not influenced as much by environmental conditions as that of other CPFs. Percentage FDK was also higher in fields previously treated with GF in 2000 and 2001. Because of the nature of this study, we could not determine if the association between previous GF use and FHB development was a cause-effect relationship. Thus, further research is needed to elucidate the nature of this association and the underlying mechanisms.