INHIBITION OF GROWTH OF SOME SEED-BORNE FUNGAL PATHOGENS BY EXTRACT FROM BACILLUS SUBTILIS
AbstractPure culture of Bacillus subtilis isolated from barley seeds and grown on malt extract agar medium in Petri dishes was screened against a wide range of seed-borne fungi in 100ml malt extract broth medium in flat-bottom flasks for antagonism. A plug of the bacterium and/or a plug of the fungal mycelia/spores (0.6cm, diameter) was put into the broth in each flask and incubated for 7 days. Bacillus subtilis was found to be antagonistic against Alternaria brassicae, Alternaria brassicicola, Alternaria dauci, Alternaria linicola, Alternaria radicinia, Ascochyta fabae, Colletotrichum lini, Fusarium culmorum, Fusarium moniliforme, Macrophomina phaseolina, Pyrenophora graminea, Pyrenophora teres and Stemphylium botryosum. Mean percentage inhibitory effects of B. subtilis on the dry weight of the fungi are: A brassicae (43.0%), A. brassicicola (37.9%), A. dauci (42.7%), A radicina (36.2%), A. linicola (38.5%), A. fabae (58.3%), C. lini (52.8%), F. culmorum (54.5%), F. moniliforme (55.9%), M. phaseolina (47.6%), P. graminae (45.7%), P. teres (40.0%) and S. botryosum (58.1%). The bacterium had the greatest inhibitory dry weight effect on Ascochyta fabae (58.3%) and the lowest effect on A. radicina (36.2%). The bacterium extract (fengymycin) alone was screened for antagonism against the same seed-borne fungi on potato dextrose agar medium in Petri dishes and the extract inhibited the growth of the fungi. The bacterium slurry was found to be non-phytotoxic to barley, maize, wheat, mung bean and soyabean seeds. The importance of biological control in crop disease management is discussed.
KEY WORDS: Bacillus subtilis, fengymycin, pathogenic seed-borne fungi, antagonism, crop seeds.
Global Jnl Pure & Applied Sciences Vol.10(1) 2004: 17-21