Abstract
Two pot experiments were conducted at Lumle Centre in the 1991 and 1992 seasons to evaluate the effectiveness of maize (Zea mays L.) seed treatment with triadimenol (Baytan), Sumi-8 (diniconazole), and tebuconazole (Raxil-50) in the prevention of head smut (Sphacelotheca reiliana). In both years these fungicides effectively controlled the disease since the plants from treated seeds suffered less than 3% smut. These fungicides were tested next under conditions of artificial exposure at three mid-hill sites in farmers' fields in the 1994 season except that propiconazole (Tilt-250) replaced Sumi-8. Propiconazole, tebuconazole, and triadimenol were applied at the rate of 4 mL or 4 g kg·1 of maize seeds. The lowest number of smutted plants was produced by propiconazole (0.7%), and followed by teuconazole (6.1%) and triadimenol (13.2%) treatments while the untreated control suffered 35.9%. The per cent head smut control by the three fungicides was highly significant (P < 0. 001) compared with the untreated control. Propiconazole treatment of seed produced a stunting effect at the seedling stage from which the plants recovered later in the growth phase. However, 2-3 ml propiconazole kg·1 seed treatment produced relatively less detrimental effect on germination or seedling growth.
