Incidence and Severity of Anthracnose (Colletotrichum musae Berk. & Curt. V. Arx.) and Evaluation of Postharvest Handling Factors affecting Disease Development on Marketed Banana Fruits in Addis Ababa, Ethiopia

Abstract

Anthracnose caused by Colletotrichum musae (Berk. & Curt. V.) Arx is one of the most important postharvest diseases of marketed banana fruits at the global level and often the disease is mentioned in relation to customary harvest and postharvest management practices (CHPHMPs) by growers and traders. However, in Ethiopia the status of the disease, characteristics of the pathogen, the reaction of detached banana genotypes against the pathogen and the effects of CHPHMPs on the disease are not well studied. Therefore, the current study was done with the objectives of determining the incidence and severity of anthracnose starting from farm up to retailer shops, surveying the CHPHMPs affecting the disease, characterizing Colletotrichum musae isolates and to determine the reactions of some banana genotypes against the disease. Survey and sampling of the study was conducted in farmers’ field around Arba-Minch and major fruit markets in Addis Ababa and laboratorial works were conducted at Plant Pathology Laboratory of JUCAVM. Data on CHPHMPs of the farmers and traders were collected through single visit interviews using questionnaire format. Disease incidence was determined on the bases of totality of healthy and diseased fruits and severity was visually estimated and calculated by giving the scale from 0 to 4. Survey study revealed 9.8% and 4.1% incidence and severity of anthracnose, respectively at farmers’ field. After transportation of the fruits to Addis anthracnose incidence was 12.2% with 3% of severity on assessed banana fingers. Disease incidence and severity were recorded as 30.4 and 2.6% at ripening rooms, 70.8 and 31.6% at retailer, 51.3 and 20.7% at ET-fruit shops, respectively. The CHPHMPs both by farmers and merchants were almost comparable however, some variations were observed. Among surveyed CHPHMPs variety, harvesting methods, fruit sources, the distance travelled, fruit covers during transportation, cleaning/ grading, container type and from physical condition of the fruits (PCF) bruise severity on fruits surface and ripening level in general were factors significantly (p < 0.05) affected the disease at different phases of the study. The six isolates C. musae were also showed significant variation in some of their cultural and morphological characteristics on PDA and blackish white colony color, black substrate color, flat mycelium growth, regular colony shape with smooth colony margin were typical and dominant cultural characteristics of most of the isolates. In addition to these, some banana varieties were significantly (p < 0.05) different in their susceptibility to wound and quiescent anthracnose based on their rotted surface area among which William I, was found to be susceptible with rotted surface area of 3522.2 and 2521.9 mm2 whereas butaza was the least susceptible for wound and quiescent anthracnose, respectively. Generally the study found anthracnose as an important postharvest disease of banana fruit causing qualitative and quantitative loss in many of the surveyed shops in Addis Ababa and the disease was found to be affected by CHPHMPs. Therefore, it is better to conduct further studies regarding the disease in relation to management practices and the loss need to be quantified. In addition to this it is important to study reactions of more number of commercial bananas to quiescent and wound anthracnose.