Management of bulb rot of onion caused by Erwinia carotovora pv. carotovora

Abstract

The bulb rot caused by Erwinia carotovora pv. carotovora is major important disease of onion is difficult to control without application of bactericides and fungicides respectively. Erwinia carotovora pv. carotovora causes 40 to 80% losses in onion. In present investigation studies were undertaken to manage bulb rot disease of onion through the use of bactericide and fungicides. Efficacy of different chemicals was tested by filter paper disc diffusion method against Erwinia carotovora pv. carotovora. Maximum growth inhibition of Erwinia carotovora pv. carotovora recorded in copper oxychloride @ 0.25% + streptomycin @ 200 ppm (23.00 mm), followed by streptomycin @ 200 ppm (18.00 mm). Under field condition, treatment with bulb dip in copper oxychloride @ 0.25% + streptomycin sulphate @ 200 ppm + spraying with copper oxychloride @ 0.25% was found most effective treatment against bulb rot of onion as it recorded minimum disease incidence (19.67%) with maximum disease control (53.46%). Maximum seed yield obtained in treatment with bulb dip copper oxychloride @ 0.25% + streptomycin 200ppm + spraying with mancozeb @ 0.25% + carbendazim @ 0.10% + copper oxychloride @ 0.25% i.e 1022 kg/ha which was found significantly superior over rest of the treatments.