Associated fungal pathogens and causes of postharvest losses in the avocado value chain in Hossana Town Market, Ethiopia

Abstract

A significant proportion of post-harvest loss of agricultural produce is experienced in Ethiopia, especially in perishable horticultural commodities like fruits (mango, banana, papaya, avocado, sweet orange) and vegetables. Postharvest diseases derived from biotic sources such as microbial pathogens, or physiological disorders caused by abiotic sources contribute to shortening the postharvest life of the avocados, leading to loss in fruit quality. This study aimed to assess post-harvest losses and identify post-harvest pathogens associated with the decay of avocado fruits in Hossana town shops and a market which opens once a week. Random sampling method was used to select shops for survey and sample collection. Avocado fruits with different damage levels and disease symptoms were collected from 14 shops and the Hossana Market, packed using cartons then transported to the laboratory. A survey was conducted in selected shops and the market and identification of disease-causing pathogens was done through incubation of the samples taken from different parts of the fruits using potato dextrose agar (PDA) for seven days. Data was analyzed using SPSS, statistical software. Results from the survey revealed that postharvest loss of avocado varies across different postharvest handling stages and the highest loss was recorded during storage (40%) followed by harvesting (26.7%). The most mechanical damage was observed in the MS shop (100%) followed by the HM (83.3%). This may be due to poor harvesting practices: unsuitable field or marketing containers and crates, which may have fractured wood, sharp edges, poor nailing or stapling. Disease incidence assessment showed that in three shops (AD2, MN2 and MS), 100% of fruits were infected. The highest disease severity index rated as 5 (>75%) was also observed in the same three shops (AD2, MN2 and MS) and the HM, followed by 3 shops (AD3, GM3 and NR) rated as 4 (51-75%). A total of 82 fungal colony growths were observed with Colletotrichum gloeosporioides being the most frequently isolated species (60 %) followed by Fusarium spp (26.67 %). Appropriate post-harvest handling technology and disease management strategy should be implemented from farm to fork to reduce post-harvest losses.