Biological control of blackleg of beet (Phoma betae) by Metarhizium anisopliae.
1993
Roberti R. | Ghisellini L. | Innocenti G.
Two strains of each entomogenous fungi (Beauveria bassiana, Beauveria brongniartii, Metarhizium anisopliae, Paecilomyces farinosus and Verticillium lecanii) were evaluated for their activity against Phoma betae under greenhouse conditions and in the field. Phoma betae was artificially inoculated into soil and entomogenous fungi were applied on beet seeds; iprodione (1 g a.i./kg seed) was used as chemical control. Under greenhouse conditions (exp. 1) M. anisopliae 37 and 36 and B. bassiana 142 and 140 significantly reduced disease incidence with respect to the untreated control. However, M. anisopliae 37 was the best antagonist. It also proved to be effective in reducing disease incidence in the field and gave results similar to those obtained with iprodione. No phytotoxic effects of M. anisopliae 37 on seedlings were observed. The mechanism of action of M. anisopliae 37 was investigated. The production of volatile and non volatile metabolites by the antagonist and the hyphal interaction between M. anisopliae and P. betae were studied. It was found that the antagonist produced active non volatile metabolite or metabolites but no active volatile compounds. Between the two fungi, a clear inhibition area (35.75 mm) was observed and no hyphal interaction.
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