Population dynamics of Dickeya zeae in different rice and maize based cropping systems in Punjab

Dickeya zeae attacks maize crop causing bacterial stalk rot and is found to be associated with bacterial foot rot of rice during Kharif season in Punjab. The populations of Dickeya zeae are highly dynamic temporally in different crop rotations prevalent in Punjab. Due to the wide host range and survival of pathogen in debris for a long period of time, this bacterium is difficult to manage. For integrated disease management, crop rotations play a major role by curbing the pathogenic population. For this purpose, an experiment was laid by keeping ten different crop rotation treatments in rice and maize based cropping systems. In rice based crop rotation, it was found that keeping a period of fallow land (in hot months of May and June) before sowing the main rice crop or a rotation with nonhost crop i.e. wheat has reduced the soil bacterial population upto 99.2 and 98.2 per cent, respectively. Whereas in maize cropping system, green manuring with sunhemp proved more beneficial in reducing soil population of upto 98.6 per cent. Growing potato after the main crop was less detrimental on bacterial population as it helps to sustain the populations to a greater extent.