Alemu Nega, Fikre Lemessa and Gezahegn Berecha
Maize (Zea mays L.) is one of the most important cereal crops used in the human diet in large parts of the world as well as in Ethiopia and its production are limited by diseases such as grey leaf spot caused by a fungus Cercospora zeae-maydis. Currently grey leaf spot has become the most important threat to maize production in maize belt areas of Ethiopia causing significant yield loss. The objective of this study was therefore, to assess the distribution and importance of maize grey leaf spot in south and southwest Ethiopia. The field assessments were conducted during the year of 2014 cropping seasons by sampling 110 farmer fields in 11 districts selected from two zones of Oromia region and two zones of Southern Nation, Nationalities and People region (SNNPR). The result revealed that the disease occurs in the entire assessed districts having different agro-ecological zones. Maize grey leaf spot was prevalent in all surveyed farms of south and southwest Ethiopia, 74% of maize fields were infected by grey leaf spot. However, the mean incidence and severity of grey leaf spot on maize was significantly varied from district to district. The highest grey leaf spot incidence (71.2%) and severity (46.2%) was recorded in Boricha district, while Damote Gale had the lowest mean incidence (51.8) and severity (33.5%). Among the surveyed four zones in two regions, the highest incidence was found in Sidama (65.6%) and Illubabore (63.1%) followed by Jimma (62.5%) and Wolaita (57.6%). The highest mean severity of maize grey leaf spot was observed in Sidama (44.5%) followed by Illubabore (43.7%) and Jimma (42.63%) while the lowest severity was recorded in Wolaita (36.4%) zone. The disease was more severe in intermediate/humid areas with intermediate annual rainfall. The current study revealed maize grey leaf spot pressure in maize farms of south and southwest Ethiopia and the need to design an efficient, inexpensive and sustainable management approaches against the pests.