Assessment and Distribution of Foliar and Soil-Borne Diseases of Capsicum Species in Ethiopia

Abstract

Diseases caused by fungi and oomycetes lead to reduced productivity of pepper (Capsicum spp.) in Ethiopia. Currently, knowledge about severity and geographical distribution of fungal diseases in pepper producing areas is limited. Thus this study was aimed: to map the geographical distribution of economically relevant Capsicum diseases and to identify, document, prioritize, and update the status of fungal infectious diseases across the country. A survey was conducted throughout major pepper agro-ecological zones in Ethiopia for two consecutive years, 2018 and 2019/20. Districts were surveyed based on pepper production at intervals of 4 to 10 kilometers from each sampling zone of major pepper growing areas. Global positioning system (GPS) was used to mark each sampling point using a GPS receiver for altitude and coordinates. Nine major pathogenic fungi were identified in samples collected from different pepper-producing areas across the country.  Cercospora leaf spot caused by Cercospora capsici was found prevalent in 39.8% of the 133 fields studied, followed by Fusarium wilt caused by Fusarium oxysporum f. sp. capsici, and Phytophthora collar, root, and fruit rot caused by Phytophthora capsici, prevalent in 21.1% and 15.8% fields, respectively. The maximum overall mean percent severity index (69.5%) was recorded for Fusarium stem and root rot (Fusarium solani) followed by damping-off (56.7%) and Fusarium wilt (55.4%). The current study indicated the importance of fungal diseases, particularly soil-borne diseases. The molecular characterizations, primers development for important pathogens, and genome-wide screening of Capsicum genotypes in Ethiopia required to advance environmentally safe and affordable disease control methods.