Evaluation of management of bacterial stalk rot of maize (Dickeya zeae) using some chemicals and bio-agents

Abstract

A virulent strain (M-13) of Dickeya zeae causing bacterial stalk rot of maize, isolated from Hoshiarpur district of Punjab was tested against different antimicrobial agents. Five antibacterial chemicals viz., stable bleaching powder, streptocycline, cristocycline, blitox, kocide and one bioagent (Pseudomonas fluorescens) were evaluated against D. zeae under in vitro and in vivo condition. The chemicals were tested with different concentrations i.e. 50, 100, 200, 500, and 1000 and >1000 ppm and bioagent supernatant used as such without any dilutions. All the test chemicals and bioagent (P. fluorescens strains) reduced the log cfu/ml of D. zeae. Amongst chemicals, stable bleaching powder with 100 ppm concentration showed most effective antibacterial activity which reduced the population of D. zeae with 6.35 log cfu/ml and amongst P. fluorescence strains, MPF-5 strain showed effective result with 8.07 log cfu/ml. In field condition bleaching powder also showed good result to reduce the disease severity with increased the crop yield when used as both methods (drenching and dusting). However, post inoculation drenching with 100ppm concentration showed minimum mean of disease severity (7.13%) with high yield (7.4 kg) in all three maize cultivars (Dekalb Double, Punjab Sweet Corn-1 and PMH-1). The increase yield per cent as compared to control was 52.4% in Dekalb Double, 64% in Punjab Sweet Corn-1 and 57.9 % in PMH-1 maize cultivars.