Effect of Fungicide and Nitrogen Combinations on Spring Wheat Production in Ontario.

Leaf and head diseases represent a main challenge for spring wheat producers in Ontario. The latest generation of fungicides might offer better control of these diseases and improve wheat yields and quality. The objective of this study was to evaluate the effect of fungicide and nitrogen (N) combinations on selected parameters of spring wheat varieties grown in four locations across Ontario between 2010 and 2012. Sixteen treatment combinations were obtained using four fungicide levels (three commercial fungicides and one untreated control) and four N levels (0, 90, 120 and 150 kg N ha^-1). Treatments receiving 150 kg N ha^-1were also sprayed with a growth regulator to reduce lodging risk. The fungicides Proline, Prosaro, and Caramba were applied to their respective treatments at their recommended rates and timings. All treatments receiving fungicides were also treated with Stratego.

Results from 9 site/years show that except for the southernmost location, N applications between 90 and 150 kg N ha^-1 did not significantly affect yields, test weight, or thousand kernel weight. However, protein content increased with higher N applications. Response to fungicide applications differed among sites. In general, where there was an effect of fungicide application, Prosaro resulted in the highest yields. Caramba effects were mixed and it even resulted in lower yields compared to untreated control in certain cases. The fungicide application decreased the percentage of fusarium-damaged kernels.