EFFECT OF FUNGICIDES ON SEPTORIA LEAF AND GLUME BLOTCH, FUSARIUM SCAB, GRAIN-YIELD, AND TEST WEIGHT OF WINTER-WHEAT

During 1974 and 1975, winter wheat [Triticum aestivum] yields were reduced up to 15-20% by S. tritici, S. nodorum and F. roseum f. sp. cerealis ''Graminearum'' as measured by yield response to fungicides. Wheat yields were 20% higher in 1974 in plots treated with mancozeb or mancozeb plus benomyl, and 15% higher when treated with benomyl alone. Yields were increased 15% in 1975 by mancozeb plus benomyl, and by 7-11% by benomyl or MBC (methyl 2-benzimidazole-carbamate). Mancozeb or mancozeb plus benomyl gave better control of S. tritici than did benomyl or MBC. Infection of heads by S. nodorum was reduced from 57% on nonsprayed plots to 8-22% by fungicide treatments. F. roseum infection of grain was reduced from 24% in nonsprayed plots to 12% in plots treated with mancozeb plus benomyl and to 4-8% in plots treated with MBC or benomyl. Test weights were increased 1.2-2.0% by fungicide treatment in 1974.