Study interactions between variety resistance and fungicide application (product and timing) to control foliar disease. Measure effect of higher plant population on reducing tillering, thus reducing the variability in growth stage across a field, and allowing a better assessment of optimal timing for fungicide. Examine how integrated disease management strategies vary between locations within the primary milling oat production area.
Studies on integrated disease management (IDM) have shown that utilizing several management practices simultaneously is often most effective for disease control in crops. In oats (Avena sativa L.), the efficacy of fungicide application for preserving oat yield and quality has been shown to vary with varietal disease resistance. Further, studies have suggested that increasing the seeding rate can be effective in reducing tillering in cereals, subsequently resulting in more uniform crop development and better fungicide application timing and efficacy for head disease but thicker crop canopies which could increase leaf disease. Thus, the objectives of this study were to assess the integration of genetic disease resistance, seeding rate, and fungicide application timing for disease management in oats. A small plot research study was conducted at Indian Head, Melfort, Redvers, and Yorkton, Saskatchewan in 2018, 2019, and 2020. A randomized split-plot design was utilized with fungicide timing (Untreated, Flag leaf, Heading) as the main plot, and variety (CS Camden, Summit) and seeding rate (300 or 450 seeds/m2 ) as sub-plots. The 12 treatments were each replicated four times at each location in each year. Conditions were not highly conducive to disease development at any of the locations or years of the study. Effects of variety, seeding rate, and fungicide were all dependent on environments. There were often variety by seeding rate interactions, but seeding rate and variety effects were nearly always independent of fungicide treatments. Effects of fungicide application were inconsistent and often inconclusive, as untreated treatments performed as well as either of the fungicide application timings, even when there were significant differences between the treatments. Fungicide effects and interactions with variety or seeding rate would likely have been more frequent and consistent if environmental conditions had been conducive to disease development. It is recommended that producers continue to combine several practices to manage disease in oats, as the effects can be additive, if not interactive. The effectiveness of applying fungicide for disease management did not appear to vary with varieties or seeding rates in this study. Thus, the decision to apply fungicide, and at what timing, should be based on environmental conditions being conducive to disease development.