Abstract

MICHEL-ACEVES, Alejandro Casimiro et al. In vitro biocontrol of Fusarium subglutinans (Wollenweb. and Reinking) Nelson, Toussoun and Marasas and F. oxysporum Schlecht., causal agents of "Witches' broom" of mango (Mangifera indica L.) by Trichoderma spp.. Rev. mex. fitopatol [online]. 2009, vol.27, n.1, pp.18-26. ISSN 2007-8080.

The antagonistic effect of native strains of Trichoderma spp. was evaluated in vitro against Fusarium oxysporum (Fo) and Fusarium subglutinans (Fs), causal agents of mango "witches' broom". Ten strains of the antagonistic fungus were isolated, one of which was selected and identified to the species level (T. harzianum); this species showed the highest percentage of antagonism inhibiting mycelial growth of Fo by 62.9% and 42.0% of Fs. In dual cultures between Fo and/or Fs with the selected strains of Trichoderma, the time for the first contact for Fo was between 3 and 4 days, and between 2 and 3 for Fs. The greatest intersection area (0.87 cm) was observed in T. lignorum against Fo, while the intersection area in Fs with the native strain Thzn-2 was 0.85 cm. Native strains Thzn-2 and Thzcf-12, and the commercial one showed antagonism class 2, being able to stop growth of both plant pathogens. Strain Thzn-2 is promising as an alternative for biocontrol of Fo and Fs; however, it is necessary to evaluate it under field conditions.

Keywords : Trichoderma harzianum; T. lignorum; antagonism; inhibition.

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