Studies were carried out to evaluate different carriers for shelf life of Pseudomonas fluorescens stored at 25±20
C
over a storage period of 6 months. The population dynamics was recorded at monthly intervals. The population
of P. fluorescens was increased significantly in all carriers i.e Talc, Spent mushroom substrate (SMS) a waste
product of mushroom industry, Lignite, Charcoal, Farm yard manure (FYM) and Flyash up to 60 days storage and
there was slow decline in number of viable propagules after 60 days of storage.Spent mushroom substrate (78×
108
cfu/g) and fly ash (53.67× 108
cfu/g) maintained viable population count at 90 days of storage.This population
was very close to the population recorded in carrier’s viz., Talc (86.33×108
cfu /g), Lignite (80×108
cfu /g) which
were usually used in biofertilizer industry. Hence for short storage period, option of SMS and Fly ash can be used
for developing commercial formulations of P. fluorescens. Talc was found to be the best carrier material that
maintained better population of the P. fluorescens (18 ×108
cfu/g) till the end of storage period.