Resumo

HERNANDEZ GONZALEZ, Yvo; PAREDES NINO, Claudia  e  CARDENAS, Harvey. In vitro sensitivity of Mycosphaerella fijensis Morelet to rachis ferments of plantain and fungicide. Agronomía Trop. [online]. 2014, vol.64, n.1-2, pp.31-38. ISSN 0002-192X.

Black Sigatoka is one of the most damaging disease that attacks plantain cultivation. In order to evaluate the in vitro susceptibility of the fungus to horn plantain rachis ferments, a trial was conducted at the Universidad Nacional Experimental Sur del Lago (UNESUR) and the Centro Internacional del Plátano (CIPLAT), Venezuela. Media agar-water (16%) were prepared with rachis ferments, 2 and 4 months old, and two fungicides (propiconazole and benzimidazole), using six Petri dishes per treatment and five leaf samples of 2 cm² per dish, placed in a humid chamber for 48 hours, and incubated for 1 hour at 26 °C in darkness. Number of germinated and not germinated spores were counted, as well as, the number of short, distorted, long hyphae and length of long hyphae. It was determined the chemical and mineral composition of each extract. Data were analyzed using descriptive statistics making a comparison test of means (ANOVA). The results showed a lack of sensitivity of the fungus to different chemical fungicides used, while in the presence of ferments there was greater inhibition of germination and growth of the pathogen. Chemical analysis of the extracts showed the presence of most of nutrients, such as potassium, and saponins that can inhibit growth of the pathogen. These results demonstrated that the ferments of plantain rachis can control (Mycosphaerella fijensis Morelet) in vitro conditions, therefore their effectiveness should be evaluated under field conditions.

Palavras-chave : sigatoka negra; plantain; resistance; pathogen; efficiency.

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