Mycelial sensitivity of Cercospora beticola to copper oxychloride

Leandro Alvarenga Santos, Janaina Marek, Lívia Costa Mariano, Laís Cristine Werner, Cacilda Marques Duarte Rios Faria

Resumo

Cercospora leaf spot or Cercospora spot, caused by Cercospora beticola Sacc is the most common disease in the leaf beet cultivation. This study aimed to determine the mycelial sensitivity in vitro, measured by the IC50 (concentration for 50% inhibition of mycelial fungus growth) of five isolates of C. beticola of sugarbeet leaves obtained in Guarapuava region (PR) to the fungicide copper oxychloride used for controlling the Cercospora spot as well as the production of cercosporin. We tested six copper oxychloride concentrations (1260.0 ppm, 126.0 ppm, 12.6 ppm, 1.26 ppm, 0.126 ppm and 0.00 ppm of the active ingredient). The concentration of 0.00 ppm represents the control without addition of the fungicide and 1260.0 represented the recommended field dose. The assessment of mycelial growth was carried out measuring the diameter of the colonies, where the fungal growth in the control treatment has reached the border of the petri dish. The experimental design was completely randomized with three replications. As for the fungus toxicity of the tested copper oxychloride active ingredient doses, it became clear that for the three isolated IC50 copper oxychloride reached sensitivity values. For analysis of cercosporin was no significant statistical difference for the different isolates and different concentrations of copper oxychloride.

Palavras-chave

Beta vulgaris L. ; copper fungicide; fungitoxic; IC50; cercospora spot.

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