In vivo application of these two rhizospheric bacteria by spraying
on the foliar parts showed encouraging observations. Spraying
of fully grown cultures of VBC7 and VBK1 twice on jackfruit foliage,
one before appearance on inflorescence and the other immediate
after, could reduce the incidence of rot formation in fruits by four
times and six times by the strains respectively in comparison to
their uninoculated controls (Table 2). In planta challenge studies
by applying pathogenic spores before spraying of VBC7 or VBK1
was not possible due to ethical reason but if had done would definitely
have give better impression about the direct control of the
pathogen. Not only the strains VBC7 and VBK1 grew well on the
fruit surfaces but also they worked efficiently to kill invading
pathogens. Functioning of rhizobacteria in phyllosphere or vice
versa has also been reported by Bashan and Holguin (1998).
Although in planta challenge study was not conducted but
in vivo experiments were performed challenging postharvest
immature fruits with R. stolonifer spores (104 spores/ml) followed
by application of all five biocontrol organisms (107–108 CFU/ml).
Such application of biocontrol agents particularly the food grade
lactic acid bacterial strains give effective result in preventing the
rot formations (Table 2). The results reveal that in completely
uninoculated control set, rot formation naturally occurs in 28%
fruits in 10 days and 60% in 15 days whereas pathogen application
to the fruits induce rot formation in 60% samples within five days
and almost 100% damage in 10–15 days. On the contrary biocontrol
agents when applied prior to challenge with pathogenic spores
almost complete prevention of rot formation in the fruits were
noticed up to 10 days and only 4–27% rot after 15 days incubation