Management of potato scab (Streptomyces scabies) by seed treatment with chemical and biocontrol agents

Abstract

Scab disease of potato, caused by various species of Streptomyces, is a bacterial disease which is an important limiting factor which affects potato yield, both quantitatively as well as qualitatively. It has worldwide occurrence and in northern India, it has assumed serious proportions in certain potato growing regions of the states of Punjab, Himachal Pradesh and Jammu & Kashmir, and may imperil the potato seed industry. For the management of this disease, an integrated approach is needed and seed treatment is an integral part of this strategy. So, during the current experiment in vitro and in vivo evaluation of different chemicals and biocontrol agents was done against Streptomyces scabies causing the scab disease of potato at PAU Ludhiana, so as to devise a seed treatment technique for the efficient management of this disease. During the evaluation of different chemicals/biocontrol agents against Streptomyces scabies, it was observed that Streptocycline, streptomycin, boric acid and copper sulphate were effective in inhibiting the development of S. scabies in vitro and in vivo. However, under field conditions, it was observed that certain antibacterial chemicals like Kocide @ 0.2% and Streptocycline @ 100 ppm and biocontrol agents like antagonistic Streptomyces spp. strain S25 and S27 had a negative impact on the germination of potato seed tuber.