1School of Organic Farming, Punjab Agricultural University, Ludhiana-141 004, India
Department of Plant Pathology, School of Organic Farming, Punjab Agricultural University, Ludhiana-141 004, India
*E-mail: gurveersinghbrar777@gmail.com
Online Published on 20 May, 2025.
Biocontrol agents such as Bacillus subtilis are widely used against soil-borne plant pathogens. Mass production and shelf life are crucial for the commercial success of bioformulation against plant pathogens. The microbial cfu count declined with an increase in the storage time. The talc-based bioformulation of Bacillus subtilis B4 was evaluated for shelf life at different temperatures (ambient, 25°C, 4°C and 0°C) in the polythene bags. The initial microbial count for the bacterial antagonist i.e. B. subtilis B4 the initial inoculum density at zero day was 8.3 × 1010 which gradually decreased to 3.4 × 104 after 360 days at ambient temperature. Still, the decline was not so prominent at 0°C after 360 days (7.1 × 105). There was a significant interaction between temperature and storage time Treatment combinations (T: Temperature; M: Month) T1M0, T2M0, T3M0 and T4M0 i.e. 8.3 × 1010 cfu/g, exhibited significant counts as compared to other treatments combinations. Storage of talc-based bioformulation of B. subtilis B4 at 4°C and 0°C was more suitable than storage at 25°C and ambient temperature. The current findings indicated that to maintain the spore viability and effective threshold density above 106 Cfu/g (colony forming units/g of formulation) at ambient for sixmonths. However, the effective cfu count (106 Cfu/g) of B. subtilis was maintained for 11 and 9 months at freezing (0°C) and at 4°C temperatures, respectively.
Bacillus subtilis, Shelf life, Talc, Bioformulation
