Effect of different tillage systems on disease dynamics of spot blotch of wheat

To assess the effect of different tillage system in conservation agriculture (CA) on spot blotch of wheat, an experiment was conducted in the experimental farm, Bidhan Chandra Krishi Viswavidyalaya, West Bengal. Seeds of five wheat varieties (DBW 39, DBW 107, HD 2967, CBW 38, DBW187) were cultivated under zero, reduced and conventional tillage conditions. Reduced tillage exhibited the lowest average percent diseased leaf area (DLA%) (16.34%) and lowest area under disease progress curve (AUDPC) (507.87), while highest average DLA (20.61%) and AUDPC (701.47) were observed in conventional tillage. DBW 39 exhibited lowest DLA under zero tillage (7.47%), whereas, highest DLA was observed in CBW 38 under conventional tillage (28.30%). Disease initiation occurred in the 4th standard meteorological week under all three tillage conditions, with maximum and minimum temperatures of 23.77 °C and 10.21 °C, evaporation at 0.99 mm, relative humidity at 99.57%, and soil temperatures at 5 cm and 15 cm of 15.66 °C and 16.91 °C, respectively. The highest DLA (%) was recorded at a maximum temperature of 33.86 °C, a minimum temperature of 20.41 °C, evaporation of 3.39 mm, relative humidity of 97.29%, and soil temperatures of 23.86 °C at 5 cm and 24.56 °C at 15 cm. Hence, reduced tillage can be used in combination with other management practices to sustainably manage the pathogen.