The Indian Journal of Agricultural Sciences (Oct 2014)

Bacillus megaterium strain NBAII 63: A potential biocontrol agent for the management of bacterial wilt of tomato caused by Ralstonia solanacearum

  • G SIVAKUMAR,
  • R RANGESHWARAN,
  • S SRIRAM,
  • P RAVEENDRAN

DOI
https://doi.org/10.56093/ijas.v84i10.44224
Journal volume & issue
Vol. 84, no. 10

Abstract

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Among 100 isolates of Bacillus spp. screened under in vitro condition, ten of them were found inhibitory against Ralstonia solanacearum which causes bacterial wilt of tomato. Bacillus isolate NBAII-63 was selected as promising one based on in vitro and in vivo screening. The promising Bacillus isolate NBAII 63 was identified as Bacillus megaterium by 16S rDNA analysis. The bio-efficacy of talc formulation of B. megaterium strain NBAII-63 was evaluated under green house and field for plant growth promotion and suppression of bacterial wilt in tomato. A combined application of seed treatment, soil application, seedling root dip and foliar spray was found effective for the management of bacterial wilt of tomato. Combined application resulted in reduction of wilt incidence to 59.9% and 56.0% under green house and field conditions respectively. Streptomycin sulphate application recorded 75.0% reduction in wilt under green house and 69.0% under field conditions. Significant increase in growth parameters, viz. root length (26.2 cm) and shoot length (74.1 cm) of tomato plants were recorded under field condition due to application B. megaterium as compared to control where it was 13.0 cm and 33.2 cm respectively. The per cent increase in root and shoot length of tomato plants due to application of B. megaterium over control was 50.3 and 55.2 respectively. Highest rhizosphere population B.megaterium of 71.2×106 cfu/g was recorded in field condition at 40 days after transplanting when the antagonist was applied as a combination of seed treatment, seedling root dip, soil application and foliar spray. Application of B. megaterium strain NBAII-63 in a combination approach such as seed treatment, seedling root dip, soil application and foliar spray significantly reduced the wilt incidence of tomato. This organism shows potential for use as a promising biological control agent in tomato.

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