Resumo

HERNANDEZ-CASTILLO, FD et al. Antifungal potential of Bacillus spp. strains and Larrea tridentata extract against Rhizoctonia solani on potato (Solanum tuberosum L.) crop. Phyton (B. Aires) [online]. 2008, vol.77, pp.241-252. ISSN 1851-5657.

Potato crop requires more fungicides than any other crop in Mexico to prevent and control several diseases. More than 21,3% of the total available fungicides are required for cropping potato. High quantities of synthetic pesticides are intended to control Phytophthora infestans and Rhizoctonia solani fungi. As a result, this produces severe health problems and ecosystem disturbances. There is then an urgent need for finding new options for sustainable management of potato crop diseases. Several experiments were conducted under laboratory, greenhouse, and field conditions, to: (1) analyze the antifungal effect of bacteria strains of the genus Bacillus, and their effect on potato plant growth; (2) determine the effect of a resinous extract from Larrea tridentata leaves against the fungus R. solani, and (3) establish if there is a synergic effect when Bacillus spp. are mixed with L. tridentata extract. Results indicate an antifungal effect of bacterial strains and Larrea extract. Bacillus strains also stimulated plant growth and yield increase. A synergic effect was detected when Bacillus spp. were mixed with Larrea extract; a similar outcome occurred with the mixture of B3, B9 and B15 strains. Results obtained with Bacillus and Larrea, as well as with their mixture are encouraging since they could be used as an organic option for biological control programs against the fungus R. solani. However, more in vivo research is necessary to validate these results.

Palavras-chave : Antagonistic bacteria; Biological control; Botanical extracts.

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