Powerful strains of Pseudomonas spp. Fluorescent tested on flax utilised in the biological control of bayoud [electronic resource].

Includes references.

Fusarium wilt of date palm caused by the fungus F oxysporum f.sp. albed/dis (Kill and Mayor) Malen,on known under the name of "bayoud", is generally considered one of the most dangerous and menacing disease of date palm in the north Africa. In Aigeria, several famous commercial varieties and clones of very high fruit quality were extinct and others can disappear because of their susceptibility towards the bayoud disease. In order to preserve these plants, one ,trategy to control Fusarium wilt is the use of antagonistic root-colonizing Pseudomonas spp. It has been demonstrated that different strains of these bacteria suppress disease by different mechanisms. Application of these biocontrol strains in interaction with the fiax, who is often used as an indicating plant in the place of date palm, which requires one longer period to have the appearance of symptoms of bayoud. The ability to suppress Fusarium wilt of fiax was tested in vivo in presence and absence of indigenous microfiora (disinfected soil and original soil) in presence of F.o.ln (=F. oxysporum f.sp. lim). The strains used of different origins showed a beneficiai effect in the suppression of disease. Antagonistic activities of DN20 strain isolated from the date palm and the strain of reference D2 straios in presence of Fusarium oxysporum f.sp. lini is very brought closer under the conditions of our experiments. The effect of antagonism in the original soil (not disinfected) for a going rate of inhibition from 94.45% to 100% more outstanding remainder, whereas in the disinfected soil, it is of about an 18.43% to 42.12%. A good antagonistic actiVity was recorded for DN20 strain under the two conditions of our experiments; on the other hand the antagonistic activities noted for the D2 strain are variable in the two types of tests. This indicates the beneficial effect of DN20 strain and the necessity of their application on his plant origin (the date palm).

Summary in Arabic.

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