Prevalence of Colletotrichum spp. Infecting Fruits in Southern Ethiopia

3 Abstract: Colletotrichum is an important fungal genus infecting several crops including avocado, papaya and banana. The current study was conducted to i) assess the incidence and severity of anthracnose of in avocado and papaya fields of southern Ethiopia; ii) identify the Colletotrichum species infecting both crops. For this purpose, field surveys were carried out in Wolaita, Wondo Genet and Ziway fruits with and without visible symptoms of anthracnose were collected; isolates were identified to a species level and characterized based on their phenotypic features. Results of the field surveys revealed the prevalence of anthracnose in all the locations. However, both disease incidence and severity varied markedly across the locations. Both incidence and severity of avocado and papaya anthracnose were found to be highest in Wondo Genet (45 and 22% for avocado and 39.7 and 22% for papaya, respectively) followed by Wolaita (32.4 and 16.8% for avocado and 36 and 16.6% for papaya, respectively). However, both anthracnose incidence and severity were lowest at 23.99% on avocado and 31.8% papaya and 13.33% on avocado and 13.67% on papaya, respectively, in Ziway. Mean monthly and annual rainfall positively and significantly (p<0.05) correlated with both incidence and severity of anthracnose. Based on morphological features, Colletotrichum isolates from both avocado and papaya fruits were identified as C. gloeosporioides. The associated Colletotrichum isolates grew optimally at 25°C (39.55mm/two days and 39.26mm/two days for isolates from avocado and papaya, respectively) and 30°C, which resulted in growth of isolates at a rate of 39.37mm/two days and40.3 mm/two days for isolates from avocado and papaya, respectively. Conidial germination was significantly and positively correlated with temperature for both avocado (r=0.559) and papaya (r=0.562) isolates.