Characterisation of volatiles produced from <Emphasis Type="Italic">Bacillus megaterium</Emphasis> YFM3.25 and their nematicidal activity against <Emphasis Type="Italic">Meloidogyne incognita</Emphasis>

A member of plant growth-promoting rhizobacteria, Bacillus megaterium YMF3.25, was demonstrated to be an efficient biocontrol agent (BCA) against root-knot nematode Meloidogyne incognita. Results from three-compartmented Petri dish tests and a pot experiment indicated that the bacterial culture could significantly inhibit the hatch of eggs and reduce infection of the nematode through production of nematicidal volatiles. After analysis by gas chromatograph/mass spectrometer and confirmation with commercial pure compounds, the nematicidal volatiles produced by the bacterium were characterised to include mainly the benzeneacetaldehyde, 2-nonanone, decanal, 2-undecanone and dimethyl disulphide, which were active against to both juveniles and eggs at the concentration of 0.5 mmol. Six compounds (phenyl ethanone, nonane, phenol, 3,5-dimethoxy-toluene, 2,3-dimethyl- butanedinitrile and 1-ethenyl-4-methoxy- benzene) with nematicidal activityies of 30%–63% also contributed to nematicidal efficacy of the bacterium.