Thirty-nine winter wheat fields in Manitoba were surveyed by MAFRD staff to visually assess the incidence and severity of fusarium head blight (FHB).
Fusarium head blight in each field was assessed by non-destructive sampling of 100 plants when most crops were at the growth stage of ZGS 73 – 85. In each field, the percentage of infected spikes (disease incidence) and the mean spike proportion infected (SPI) were determined. The FHB Index (overall severity) was calculated as (% incidence x % SPI / 100).
Symptoms of FHB were observed in all 39 fields. The average % disease incidence was 32.9% (range 1.0 – 92.0%), SPI was 33.8% (range 9.1 – 93.1%) and the resulting average FHB Index was 11.6% (range 0.1 – 47.6%). Table 1 further illustrates the average FHB Index in the three regions of Central, Eastern/Interlake and Southwest, and the number of fields surveyed per region.
The 2014 FHB Index of 11.6% was higher than the 10-year (2004-2013) average of 3.4% (see Table 2), and the third highest in the same time period.
High levels of FHB symptoms were measured in 2014 due to a number of factors, including favourable conditions for inoculum development and subsequent infection of the crop, variable crop staging resulting in difficulty timing a fungicide application for suppression of FHB, and the large number of acres grown to varieties that are rated susceptible (S) to FHB.
Samples of infected heads were also collected and sent to AAFC for further analysis of Fusarium species responsible for infection. Results will be available in the fall/early winter.
Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist
MAFRD Staff who conducted surveys: Ingrid Kristjanson, Dennis Lange, Earl Bargen, Derek Chomokovski, Rejean Picard, Amir Farooq, Lionel Kaskiw, Elmer Kaskiw, and Pam de Rocquigny.
A special THANK YOU to those producers who allow MAFRD to survey their winter wheat fields!