Caractérisation morphologique, culturale et pathogénique de Vertcillium dahliae Kleb., agent causal de la verticilliose de l’olivier (Olea europea L.)

Abstract

Verticilium dahliae Kleb, fungus responsable of verticillium of the olive tree causes important damages on the tree and now touches many olive growing regions in algeria. For the first estimates , the actuel impact of the desease reaches 35 %. Five isolates of the parasite from Sidi Belabes ( S1/P1,S2/P1) and from Mostaganem (S3/P1,S4/P1, S5/P1) are identified and characterized morphologically and culturally , tested on temperature and pH range , During the growing of their settlements on cultural field PDA , V8 Agar and middle pea ,Then pathogenic due to the study of the reaction on anoter plant, tomato (Solanum lycopersicum). The different field of cultural and the variation of the pH affect on the growing and the aspect of fungal cultural.The isolates of verticillium dahliae present a growing and optimal sporulation on field V8 agar at pH 6.5 and temperature of 22%C. The pathogenicity of three isolates of V. dahliae tested by artificial inoculation on three tomato varieties, at the rate of 10 seedling by isolate and variety gave to estimate the (F.A.I ) Foliar Alteration Index. The observed symptoms (leaf foliage ,yellowing and droping leaves) gave evidence of the important power of the isolate pathogenic S3/P1 from the region of Bouguirat (Mostaganem).