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Enhanced sporulation, morphological and pathogenic characterization of Mycosphaerella fijiensis, causal agent of Musa Black leaf streak

Abstract:

The present work focuses on enhanced sporulation, morphological and pathogenic characterization of Mycosphaerella fijiensis (CCIBP-1 and CCIBP-88) strains. They were incubated with continuous fluorescent light and temperature was maintained for 10 days at 20 ºC, 3 days at 5 ºC and 10 days at 20 ºC, respectively. Conidia number was counted per culture media. Random conidia and conidiophores were measured and cultural characteristic were also evaluated. Pathogenecity test was performed on eight-week-acclimatized plants of Grande naine (AAA. Cultural colonies characteristics of strains CCIBP-Pf 80 and CCIBP-Pf 88 were raised, velvety, dark stromatic mycelia and compact. Green, pink and grey colors were predominant on superficial mycelia of both strains. Pseudocercospora conidia types were produced on all assayed cultures media in both strains but Potato Carrot Agar and V-8 media were the most appropriated for conidia production. Morphological characteristics of conidia and conidiophores were similar for both strains. In the pathogenesis test both strains produced characteristic symptoms of Black Sigatoka on all inoculated cultivars. First symptoms caused by both strains were observed 14 to 20 days after infection in all banana inoculated cultivars. Disease development time was around 70-75 days when appeared the first matures necrotic lesions with dry centers.