Status of Wheat Septoria Leaf Blotch (Septaria tritici Roberge in Desmaz) in South West and Western Shewa Zones of Oromiya Regional State, Ethiopia

Abstract

Septoria leaf blotch (Septaria tritici) is one of the most yield limiting diseases of wheat production in Ethiopian highlands. Survey was conducted during October to November, 2014 so as to assess the incidence and severity of the disease in 14 districts of South-west and West Shewa zones. A total of 97 wheat farms within 64 farmer’s associations were observed. The incidence of Septoria leaf blotch varied from 75 - 100% and severity index ranged from 4 to 89%. In West Shewa, the mean incidence was 99.8% and in Southwest Shewa it was 96.8% while the mean severity index was 53% and 55%, respectively. When wheat was preceded by cereals, the mean incidence of Septoria leaf blotch was 100% and severity index was 70%. Whereas when wheat was followed by pulse crops, the incidence reduced to 96% and Severity index to 45%. The highest mean incidence of 100% and mean severity index of 61% were recorded on bread wheat variety Danda'a, and on local variety the incidence was 100% and severity index was 67%. In the highlands of 2500-3500 m.a.s.l incidence and severity substantially increased up to 100% and 62% respectively Septoria leaf blotch incidence and severity were much more pronounced in varieties sown during July than August and September. All released commercial varieties were found to be susceptible to the pathogen, and yet the disease remained to be a threat to the production of wheat in all surveyed areas and subsequent control strategies urgently need to be devised.