Powder Formulations ofPseudomonas fluorescensto Control Pigeonpea Wilt

Pseudomonas fluorescensstrains which effectively inhibited mycelial growth ofFusarium udum,the pigeonpea (Cajanus cajan) pathogen, were isolated from the rhizoplane of different crops. Various powder formulations of two efficientP. fluorescensstrains were developed. All freshly prepared powder formulations were effective in controlling the disease, but their efficacies varied depending upon the length of storage. Talc formulations were effective even after 6 months of storage, while peat formulations were effective up to 60 days of storage. The shelf life of vermiculite, lignite, and kaolinite formulations was short. Unformulated bacterial suspensions could not be stored even for 10 days, at which time their efficacy was completely lost. The bacterial strains survived in pigeonpea rhizosphere throughout the crop-growth period. The talc-based powder formulations effectively controlled pigeonpea wilt and increased yield in two field trials. Development of powder formulations ofP. fluorescenswill aid large-scale application of biological control in farmersʹ fields.