EFFECT OF FUNGICIDES ON THE INCIDENCE OF RUST DISEASE, ROOT YIELD ANDSUGAR CONTENT IN SUGAR-BEET

Field experiments were conducted from 1988 to 1993 to assess the effec tiveness of commercially-available fungicides in controlling rust (Uro myces betae) in sugar beet and to determine whether there were economi c benefits from controlling this disease. The systemic products Corbel (fenpropimorph), Impact MBC (flutriafol + carbendazim) and Punch C (f lusilazole + carbendazim) were used in eight experiments and the syste mic product Score (difenoconazole) was used in four of these experimen ts (1990 to 1993). Single sprays with these products gave good control of rust, reducing the level of disease by 70% or greater when compare d with unsprayed controls in all years. Significant increases in the s ugar content of the roots were recorded in response to fungicide treat ment in all years when the sugar contents were determined (1989 to 199 3). Significant increases in root yield were recorded in only one tria l (in 1988). The protectant products Duter (fentin hydroxide) and Thio vit (sulphur), used in only two and three of the experiments, respecti vely, were not as effective as the systemic products in controlling ru st. Sugar was increased significantly in response to spraying with Dut er hut not in response to sulphur.