A study on the synergetic effect of Bacillus amyloliquefaciens and dipotassium phosphate on Alternaria solani causing early blight disease of tomato

A study of the effect of bioagents and dipotassium phosphate (DPP) and their combination on early blight disease reduction under greenhouse conditions was conducted. Native bacterial isolates as bio-control agents exhibited control against early blight. Five bacterial isolates were tested against the pathogen. All isolates exhibited significant antagonistic activity against Alternariasolani, isolate “bact-03” showed significant in vitro inhibition (42.6%) and later was identified as Bacillus amyloliquefaciensby 16S rDNA gene analysis. Tests conducted on dipotassium phosphate (DPP) at different concentrations (10 mM, 25 mM, and 50 mM) showed mycelial growth inhibition 14.2%, 27.4%, and 54.8%, respectively. In vitro synergetic study on seed germination showed that the combination of DPP and B. amyloliquefaciens antagonized the pathogen. Vigor index was also significant in the combination (343.0) as well as DPP (299.0), and bioagent (426.6) compared to control (170.0). In the in vivo application of B. amyloliquefaciens, DPP combination showed significant disease reduction. However, disease severity on the plants treated with DPP was 35%, and the plants treated with B. amyloliquefaciens was 30% while in combination of both showed the disease severity up to 42% that was significantly lower than control (82%). Application of these bioagents and DPP also sustained the plant weight by promoting the growth and development of plant. The results of this study indicate that naturally existing bioagents along with the slats of potassium phosphate may provide promising control of early blight disease.. Due to their antagonistism, bacterial strains with the combination of salts can be used as bio-pesticides. Their applicationsimproves seed health and crop yield, but signaling relationship in pathogens, plants, and soil still needs to divulge to promote BCAs as encouraging bio-pesticides for the future.