EFFECT OF TIMING OF PROPICONAZOLE APPLICATION ON FOLIAR DISEASE AND YIELD OF IRRIGATED SPRING WHEAT IN SASKATCHEWAN FROM 1990 TO 1992

Applications of propiconazole on spring wheat at various growth stages at Outlook, Saskatchewan showed that the optimal time to spray was be tween the extension of the flag leaf growth stage to the medium milk g rowth stage (G.S. 41-75). The maximum yield increase was about 10% on the soft white spring wheat, Fielder, compared to a 3% yield increase on the hard red spring wheat, Katepwa. The disease levels on penultima te leaves was reduced by spray applications between stem elongation an d medium milk growth stages (G.S. 31-75). Most of the foliar disease w as caused by Septoria spp. with S. nodorum being the most prevalent pa thogen; Pyrenophora triticirepentis was also present.