In vitro and in vivo efficacy of some chemicals against common scab (Streptomyces scabies) of potato

Bactericides Krosin AG and Timsen; fungicides Oxicob, Micra 72WP, Provex 200WP, and Amister Top; and plant nutrients Mag Plus and Alpha Boron Plus were evaluated against Streptomyces scabies in vitro and under field conditions. Among the chemicals, Oxicob (3500 ppm) and Krosin AG (2000 ppm) demonstrated maximum zone of inhibition against S. scabies by 20.61 and 19.74 mm, respectively in in vitro. In field, maximum reduction of common scab incidence by number (64.99%) & weight (66.02%), and severity (73.53%) was achieved by Oxicob. Along with the reduction of common scab incidence by number (49.92%) & weight (47.70%), and severity (49.47%), Alpha Boron Plus resulted the highest potato tuber yield (18.07 ton ha(-1)) in comparison to other chemicals. The present study suggests that combination of Oxicob and Alpha Boron Plus can be applied in the field to increase potato tuber yield.