The viability of bacteria was better in the irradiated peat than in
the talc powder, and irradiated peat was also a suitable carrier
material for seed coating. Although the survival of all 3 antagonistic
bacteria in both peat and talc formulations decreased over
time at room temperature, their populations remained above
108 CFU/g during 180 days of storage. Normally, an optimal carrier
material should stabilize the populations of the biocontrol bacteria
in the formulations during production to storage phase giving
them longer shelf life. Formulations also protect the inoculated
organisms from harmful environmental effects and enhance
their activity and effectiveness for plant growth promotion and
disease suppression (Van Veen et al. 1997; Jones and Burges 1998).
As described in this study, the antagonistic bacteria in formulations
can be easily applied directly to the soil, substrate, or seed.