Abstract:
Fusarium Wilt, caused by Fusarium oxysporumf.sp. cubense(Foc), is the most important disease
of banana worldwide, causing severe yield losses in commercial and local banana cultivars, but
there is limited practical research information about the epidemiology and relative importance
of banana fusarium wilt, and robust management options in Gamo zone, southern Ethiopia.
Thus, the study was conducted to (1) determine the distribution, importance and intensity of the
disease epidemics in association with agro-ecological factors, and (2) evaluate commercial
banana cultivars resistance reaction against the disease. A total of 90 farmer fields were
surveyed in three major banana growing districts during 2019 and, pot experiment was
conducted with seven commercial banana cultivars in a factorial arrangement of completely
randomized design with three replications. The associations of disease incidence and severity
with independent variables were analyzed in logistic regression model using SAS procedure of
GENMOD. Observations of external leaf symptoms and internal rhizome discoloration were
conducted to determine the response of cultivars evaluated using standard scales of leaf
symptom index (LSI) and rhizome discoloration index (RDI). The incubation period, disease
incidence, percent severity index and area under disease progress curve data were subjected to
analysis of variance (ANOVA) using the SAS software version 9.2and means were compared
using LSD test (α= 0.01). Results of the survey study indicated that Fusarium wilt incidence was
widely distributed in all the three districts, regardless of agro ecological factors. The highest
mean incidence (47.37%) and severity (46.31%) were recorded at Daramalo while the lowest
incidence (20.75%) and severity (28.63%) were from Arba Minch Zuria district. Variables like
Banana cultivars, age of plantations, weeding practice, and disease management methods were
very highly significantly (p<0.0001) associated with both incidence and severity of the disease.
Farms growing improved cultivars reduced mean incidence by 43.6% and severity by 30.1%,
compared with farms growing local cultivars. Results from the regression analysis of the
association of agro ecological factors with Fusarium wilt incidence implied the necessity of
awareness creation to all stake holders regarding distribution, importance and possible
management options. The result obtained from evaluation of cultivars showed that William and
Grand Naine were categorized resistant but Poyo and Ducasse hybrid were susceptible and
highly susceptible respectively but Butuzua, Giant Cavendish and Dwarf Cavendish were
tolerant. In addition analysis of variance revealed that incubation period and severity ranged
from 10-46 and 13.33 - 63.33% respectively. Therefore, the susceptible and highly susceptible
verities can be replaced by the resistance ones to reduce the devastation posed by the disease
and tolerant cultivars could be maintained in production with the implementation of effective
integrated disease management practices.Fusarium oxysporum f.sp.cubense(Foc) variability and
race identification and determination of crop rotation would be the future research directions.