Abstract

PONS-HERNANDEZ, José Luis et al. Phenotypic variability of Phytophthora capsici isolates in Guanajuato. Rev. Mex. Cienc. Agríc [online]. 2020, vol.11, n.8, pp.1891-1901.  Epub Dec 13, 2021. ISSN 2007-0934.  https://doi.org/10.29312/remexca.v11i8.2618.

Phytophthora capsici, is the causal agent of ‘pepper wilt’, one of the most important diseases of this crop. To establish efficient control strategies, it is necessary to know the diversity of the pathogen, for this, this research was carried out whose objective was to determine the degree of variability of 29 monozoosporic isolates obtained from pepper (Capsicum annuum L.) from six municipalities of the state of Guanajuato and two reference strains of A1 and A2. All were characterized by growth form, type of compatibility, growth at 35 °C, sensitivity to mefenoxam, and degree of virulence. The results obtained indicate that the isolates presented 5 forms of growth: stellate (62.5%), turulous (15.62%), stoloniferous (12.5%), filamentous (6.25%) and petaloid (3.12%); its growth at 35 °C was less than 30.7% compared to the control grown at 27 °C, its compatibility type was 65.5% of the A1 type, intermediate sensitivity to mefenoxam was found in 65.5% of the isolates, the rest being sensitive. The most virulent isolate was D3 and the avirulent ones were D8, D11 and D12, all from Dolores Hidalgo. There is no direct relationship between growth form, growth at 35 °C, type of compatibility, resistance to mefenoxam, and degree of virulence.

Keywords : pepper wilt; population diversity; sensitivity to mefenoxam.

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