By John Ippolito PAg, Crops Extension Specialist, Kindersley
Fusarium head blight can have significant negative impacts on both the yield and the quality of durum wheat. A commonly used tool for management of the blight is the application of foliar fungicides. The recommended application timing is very specific at 75 per cent of when the main stem heads are fully emerged to when 50 per cent of the main stem heads are in flower.
Research was conducted by the University of Saskatchewan from 2016 to 2018 to explore the effects of timing and seeding rates on the effectiveness of the foliar fungicide applications. Fungicide applications were applied to a susceptible durum wheat variety at the following stages: head fully emerged, beginning of flowering, full flowering with 50 per cent of anthers mature (recommended stage), end of flowering, early milk stage and a double application of beginning of flowering and early milk stages. An untreated check as well as a treatment where all timings were sprayed were also included in the trial.
The seeding rates used in the study were of 75 seeds/m2 and 400 seeds/m2. These seeding rates were deliberately well below and above the recommended seeding rates of 200 seeds/m2.
These trials were conducted in Saskatoon, Melfort, Scott, Outlook and Indian Head during three growing seasons. The disease pressure was high at all sites except in Scott in 2016. There was moderate disease pressure at a number of sites in 2017 and low pressure at all sites except Melfort in 2018, which was considered to be low to moderate.
Key findings of this trial were:
- The application of the fungicides in this trial did result in increased yields and reduced numbers of fusarium damaged kernels (FDK) when compared to the unsprayed check;
- when disease pressure was high the fungicide was most effective in reducing FDK when applied between the beginning and ending of flowering;
- in years of low to moderate disease pressure the window of application was smaller with it being from beginning of flowering to full flowering with 50 per cent of the anthers mature;
- late applications did not reduce the DON content of the grain, and;
- the optimum timing of fungicide application was the same for both seeding rates.
The findings of this trial indicates that in years where weather conditions are favorable for fusarium head blight development, producers may be able to extend the window of fungicide application by 2 to 3 days. The entire project report Improving Fusarium Head Blight Management in Durum Wheat is available for download.
Download the report