Antagonistic effect of rhizosphere microbes against Fusarium solani - an associated pathogen of root rot disease of mulberry.

摘要

Studies were conducted on the population of various microbes present in the root rot infected mulberry gardens from four districts of Karnataka. The microbial population varied from 24.3-70.0x104 CFU/g soil. Thirty five bacteria, five fungi and two actinomycetes were isolated from the rhizosphere soil. These bacterial and fungal isolates were screened for their antagonism against Fusarium solani, an associated pathogen of root rot disease of mulberry. Screening revealed that eight bacterial and two fungal isolates were highly antagonistic to F. solani. Nine bacterial isolates and one fungal isolate showed moderately and rest were less or not antagonistic to F. solani. All the bacteria showed highly antagonistic reactions to F. solani were Gram negative except Bacillus sp. Of these, four bacterial species were identified as Pseudomonas, three Bacillus and one Azotobacter. The fungi were identified as Trichoderma harzianum and Trichoderma virens. Among the bacterial isolates, highest inhibition of pathogen growth was shown by Pseudomonas strain-2 (65.96%) and Pseudomonas strain-1 (48.26%) followed by Bacillus strain-2 (42.61%). Similarly, among fungi the highest inhibition of pathogen was shown by, T. harzianum (47.74%). However, T. virens (23.70%) showed less inhibition. These highly antagonistic microbes can be exploited as a component of Integrated Disease Management (IDM) package against root rot disease.