Biological effectiveness of Tebuconazole under three commercial names and Epoxyconazole for control of Karnal Bunt in the field

Commercial fungicides Opus, Tacora, Velficur, and Zoll, were evaluated in the field, to determine their biological effectiveness to control karnal bunt (Tilletia indica) of wheat. A completely randomized design was used with four replications. Twenty heads in each replication of experimental line KBSUS were inoculated during the boot stage with an allantoid sporidial suspension (10,000/mL). Commercial rates indicated in the containers of each product were followed. The first application was carried out ten days after inoculation (Zadoks stages 56-58), and the second one ten days later. Inoculated spikes were threshed by hand and the healthy and infected kernels were counted to determine the percentage of infection. Other variables evaluated were a thousand grain weight (g) and grain weight per plot (kg). The biological effectiveness of the products evaluated were Opus 95.1, Tacora 82.5, Velficur 76.1, and Zoll 59.2 %. The untreated inoculated check had a mean of 81.7 % infection. There were statistical differences for the products evaluated for level of infection after arcsin transformation (Tukey, p = 0.05), and the coefficient of variation was 8.30 %. The average a thousand grain weight per treatment was 38.3, 38.7, 38.6, and 39.2 g, for Opus, Tacora, Velficur, and Zoll, respectively, and 35.7 g for the untreated inoculated check, while the average grain weight per plot was 0.396 kg, 0.388, 0.371, and 0.375, respectively, and 0.291 for the untreated inoculated check. No phytotoxic effects of treatments applied to the wheat plant were observed.