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SESSION 5: DISEASE CONTROL AND FORECASTING MODELS
P132 - Study of the effect of Pseudomonas spp.
fluorescent for the suppression of Fusarium wilt of
tomato
F. Bensaid 1 , M. Benchaabane 2
1 ENSA Elharrach Alger, Algeria; 2 University saad dahlab Blida, Algeria
E-mail: b.fatiha79@yahoo.fr
The objective of our present work is the description of the antagonistic capacities
of two strains of Pseudomonas fluorescence (S20 and CHAO) and the
nonpathogenic fungic isolate FO47 Fusarium oxysporum against
phytopathogenics agents: Fusarium oxysporum f.sp lycopersici
Assays in vitro showed that our antagonists inhibit with a high level the mycelia
growth, conidia germination and elongation of structure’s pathogens. It has been
noted the implication of antibiosis effects as those of the trophic competition. The
inhibition of these vital parameters, for the development of pathogenic, can
contribute amply in the repression of its reproduction and infection processes. The
interactions experimented in hosts plants tomato or flax (in situ assays), with the
application of the antagonists, permitted to reduce meaningful way the
development of both wilt fusarium diseases qualitatively and quantitatively. The
rates of infected plants regressed significantly and severity was low.
Soil microbial balance, between the antagonistic population and that of
pathogenic, can be modulated through microbiological variations or abiotics
additives influencing directly or indirectly the metabolic behavior microbial. In this
experiment, addition of glucose or EDTA, could increase or decrease the
resistance of soil by activation of pathogenic or antagonists, as a result of
modification and modulation in their metabolic activities. In our tests it was noted
the positive or negative effect on the pathogenic population, expressed through its
infectious capacities, by supporting its development or that of the antagonistic
bacteria by stimulating its secondary metabolic activity (synthesis of
siderophores).
Keywords: Pseudomonas spp. fluorescents, nonpathogenic Fusarium oxysporum,
Fusarium wilt, antagonism, biological - control, induced systemic resistance, soil
receptivity
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