Bacillus megaterium encapsulated in calcium
alginate microcapsules was prepared and tested for its
efficacy against sheath blight disease of rice. In laboratory
conditions, the aqueous suspension (1:100, v/v in potato
dextrose agar) of the bacterial microcapsules (1010 spores/
ml) inhibited mycelial growth of Rhizoctonia solani
([99 %) after the microcapsules were produced and stored
for 12 months at room temperature (28 ± 2 C). The survival
of the bacterium in the microcapsules in response to
ultraviolet (u.v.) irradiation and high temperature was
investigated. The survivability of the bacterium in the
encapsulated form was greater than that of the fresh cells
when it was subjected to u.v. (20-W General electric u.v.
lamp from a 25 cm distance for 48 h) and a high temperature
treatment (80 C for 48 h). Cells of the bacterium
were detected by scanning electron microscope on both the
leaf sheath and the leaf blade (in pot tests in a greenhouse)