Effect of timing of propiconazole application on foliar disease and yield of irrigated spring wheat in Saskatchewan from 1990 to 1992

application date crop yield cultivars date de traitement developmental stages etapas de desarrollo fecha de tratamiento fongicide fungicidas fungicides genetic variation growth stages irrigation leptosphaeria nodorum pathogenicity pyrenophora pyrenophora tritici-repentis rendement des cultures rendimiento de cultivos riego saskatchewan treatment date triticum aestivum variedades varieties