Report Document on Diagnosis of Banana, Yam and Other Diseases in Pohnpei

Abstract

A severe disease or condition affecting bananas at Pohnlangas, Pohnpei was reported in 2000-2001. Disease symptoms were plant decline, unthrifty growth, stunting, wilt and plant death. Significant necrosis of xylem tissues was observed inside affected banana pseudostems. Microscopic examination of diseased tissues revealed the presence of white fungal mycelium in association with diseased tissues. Fruiting bodies of the banana pathogen, Marasmiellus inoderma, were found on the exterior of several symptomatic banana plants. Isolations of fungi from symptomatic tissues onto water agar, and their subsequent culture on nutrient agar (PDA, potato dextrose agar) consistently produced cultures of the plant pathogenic fungus, Marasmiellus inoderma. A nonpathogenic species of Fusarium was recovered at the basal stem/root interface for one diseased plant. On the basis of disease symptoms and signs, and the consistent solation and association of Marasmiellus from affected psuedostems, it was concluded that the disease at Pohnlangas is stem rot, caused by Marasmiellus inoderma. No evidence of the disease known as Panama wilt’, caused by the fungus Fusarium oxysporum was found.