Abstract

NORIEGA-CANTU, David H. et al. Relationship between spore fluctuations, environmental conditions and severity of calyx spot on roselle (Hibiscus sabdariffa). Rev. mex. fitopatol [online]. 2020, vol.38, n.1, pp.1-24.  Epub Nov 27, 2020. ISSN 2007-8080.  https://doi.org/10.18781/r.mex.fit.1909-1.

The roselle (Hibiscus sabdariffa) is affected by severe diseases such as blight and spotting of the calyx (MCJ). The objective was to study the relationships between seasonal fluctuation of Corynespora and Coniella spores, pathogenic stains and blight of chalices and leaves, weather conditions and severity (MCJ) in Ayutla, Gro. Mexico. The spores were monitored, in two cycles, the fungi were isolated and the morphological and molecular identification of Coniella was performed, the study focused on pathogens reported in Mexico. The pathogenicity tests with C. diplodiella and C. cassiicola confirmed very similar symptoms between both fungi. Coniella was the most abundant (48%) and with least amount Corynespora (8.7%). The spore dynamics had a monthly and weather related fluctuation. The population dynamics of spores was closely related to the climate. The maximum and average temperatures (°C) and average global radiation (W/m2) showed significant positive correlations with the abundance of Coniella spores and the total spores, while precipitation (mm), minimum temperature, wind speed maximum (Km hr-1) and hours of solar radiation, their relations were negative with the fluctuations of Corynespora spores. The severity of leaf and calyx staining was positively and significantly correlated with the number of spores captured.

Keywords : Coniella; Corynespora; epidemiology; population dynamic.

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