Development of Formulations ofPseudomonas fluorescensfor Control of Chickpea Wilt

Pseudomonas fluorescens strains were obtained from the rhizosphere of different crops and strains that showed inhibitory action against the chickpea (Cicer arietinum) wilt pathogen Fusarium oxysporum f. sp. ciceris were selected for further studies. The efficacy of various carriers in sustaining the population of these strains in storage was assessed. In talc-based and peat-based formulations the bacteria survived even up to 240 days of storage although the population declined from 30 days. When chickpea seeds were treated with talc-based formulations, P. fluorescens survived on the seeds for at least 180 days. When the treated seeds were sown in soil, the antagonist moved to the rhizosphere and survived well in it. Biopriming of seeds increased rhizosphere population. Seed treatment with the antagonist formulation effectively controlled chickpea wilt disease in the two field trials and increased the yield. When seed treatment was followed by root zone application the efficacy of P. fluorescens formulations increased. Pseudomonas fluorescens did not inhibit the beneficial N-fixing bacteria Rhizobium and Azospirillum in vitro and seed treatment fungicides (thiram and carbendazim) were not inhibitory to P. fluorescens in vitro.