J. Agric. Res. J. Agric. Res., Tanta Univ., 32 (2): 225-241., 2006 J. Agric. Res. J. Agric. Res., Tanta Univ., 32 (2): 225-241., 2006 1 BIOCONTROL OF FUSARIUM DAMPING-OFF OF PEA BY CERTAIN BACTERIAL ANTAGONISTS BY El-kot, G. A. N*. and E. B. A. Belal** Dept. of Agric. Botany, Fac. of Agric. Kafr El-sheikh, Tanta Univ. * Plant pathology ** Agricultural Microbiology ABSTRACT Pea (Pisum sativum L.) root rots caused by Fusarium semitectum, F. solani and F. moniliforme are a major yield-limiting factor for field pea production. Different bacterial antagonistic isolates were isolated from rhizosphere-soil samples of healthy pea plants. These antagonistic isolates exhibited antifungal activity against the tested fungal pathogens. The predominant antifungal bacterial isolates belonged to bacilli and pseudomonads. They were identified as Bacillus subtilis (isolates No. 9, 10 and 6 ), B. pumilus (No. 1E) and Pseudomonas sp. (No. p). Bioassays were conducted under greenhouse conditions at the experimental greenhouse of Dept. of Agric Botany, Fac. of Agric., Kafr El-Sheihk, Tanta Univ. during the two successive seasons 2004/2005 and 2005/2006 to test the efficacy of antagonists applied to pea seeds for protection against seed rot and seedling damping-off in a field soil artificially infested with the tested pathogens. Seed coating with bacterial cell suspension of (9, 10 and 6 ) Bacillus subtilis, and B. pumilus (1E) and Pseudomonas sp. (p) (10 8 cfu/ml) significantly decreased pre-, and post- emergence damping-off and increased survival plants, stem length, number of flowers, number of branches as well as dry weight of shoots compared with the untreated seeds grown in pathogen-infested soil (control). Seed treatment with the bacterial isolates B. subtilis (No. 6 and 10) was more efficient than the other tested bacterial antagonistics in the most estimated parameters. The effects were similar in more cases to those of Benlate fungicide, which increased germination, emergence and reduced root rot severity. Results of this study suggest that B. subtilis is an effective bioagent in controlling damping – off and root rots caused by the tested pathogenic fungi and could be considered as promising alternative to existing chemical products. Keywords: Bioagents, Pisum sativum, Fusarium spp., rhizosphere, seed treatment, Biological control INTRODUCTION Pea (Pisum sativum L.) is one of the most important winter vegetables in Egypt. It grows well all over the country provinces and is