عامل بيماري پوسيدگي طوقه و ريشه برنج FUSAYIUM MONLIFOYME تاثير باكتريهاي آنتاگونيست روي

Biological control of Fusarium moniliforme,the causal agent of collar and root rot of rice by antagonistics bacteria

The antagonistic effect of some bacterial strains against Fusarium moniliforme the causal agent of collar and root rot of rice were investigated. Two hundred sixty six bacterial strains were collected from rhizosphere of infected plants from Rasht, Lahijan, Foman, Anzaly, Talesh and Astara in the Guilan Province. Antagonistic ability of 13 strains of these bacteria (8 Gram negative and 5 Gram positive) were demonstrated by using the dual culture method. According to the results of biochemical and morphological trials, the Gram negative bacteria were identified as Pseudomonas fluorescens and Gram positive was as Bacillus cereus. En determining the effects of volatile metabolites produced by antagonistic bacteria, all strains, inhibited growth of Fusarium moniliforme in vitro conditions. Culture filtrate and antibiotics produced by these strains inhibited growth of the pathogen. All P. fluorescens strains produced siderophore on Kings B contained 5, 50 and 100 miumol FeCl3 which inhibited growth of the Geotrichum candidum. The bacteria colonization experiment showed that F21, F15 and F23 strains increased their populations on rice root system by 2.28, 2.27 and 2.23 CFU logarithm. Effecte of fungicides Benomyl and Rovral T.S on strains of antagonistics bacteria indicated that these fungicides had no effect on strains when used in 1000 ppm.