Grey leaf spot disease: a potential threat to maize production in Ethiopia

• Published in: Sebil (Ethiopia) Vol. 9; pp. 147 - 157
• Main Authors: Dagne Wegary(Bako Research Center, Bako (Ethiopia)), Fekede Abebe(Bako Research Center, Bako (Ethiopia)), Legese Wolde(Bako Research Center, Bako (Ethiopia)), Gemechu Keneni(Holetta Research Center, Holetta (Ethiopia))
• Format: Publication
• Language: English
• Published: Addis Abeba (Ethiopia) CSSE 01.06.2001
• Subjects: CERCOSPORA; ENCUESTAS; ENFERMEDADES DE LAS PLANTAS; ENQUETE; ETHIOPIA; ETHIOPIE; ETIOPIA; INVESTIGACION; MALADIE DES PLANTES; MANCHAS; PLANT DISEASES; RECHERCHE; SPOTS; SURVEYS; TACHE; ZEA MAYS

A survey study was made for two year (1997-1998) in major maize growing areas of Ethiopia to assess the intensity and distribution of grey leaf spot disease. Multistage sampling strategy was followed whereby localities in the severely attacked districts were visited in each zone. The disease lesion samples collected from local and improved varieties were taken to Bako Research Center for laboratory identification of the associated pathogen and partly sent to the International Mycological Institute (IMI) for further confirmation. The results showed that grey leaf spot was widely distributed and had severe outbreaks in East and West Wellega, Jimma, Illubabor, East Shewa and Sidama zones. Higher disease intensities were recorded at Ayira Gulliso, Dale Lalo, Yubdo and Nole Kaba districts of West Wellega and Darimu, Aligiesachi, Aledidu and Bure districts of Illubabor zones in 1997. A hybrid variety BH-660 was found to be relatively tolerant while all other varieties where susceptible to the disease. Disease incidneces of 35 and 60. and severity of 4.0 and 4.5 (using 1-5 scale) were recorded from Gulliso and Nedjo areas of West Wellega, respectively during and off-season of 1998. During the main season of 1998, variety Phb-3253 at Limmu Kossa district of Jimma was very severely attacked and immaturely dried to the level it can not be rated. Likewise, the disease infection was observed to be more severe on this variety in Illubabor zone, Billito-Siraro and Awassa-Wendo Tika state farms. A single cross inbred, A-7033 x F-7215, was heavily infected (78; severity) by the disease at Shallo basic seed farm. Disease intensity was highly variable within zones, districts and localities. But generally, the expected yield loss due to the disease is higher on late sown fields as compared to the early sown ones. The laboratory evaluation of the samples at Bako Research Center and the reports from IMI indicated that the disease is grey leaf spot which is caused by Cercospora zeae-maydis.