Identification of Fusarium Species Responsible to Cause Wheat Head Blight in Southwestern Ethiopia

Abstract

Fusarium head blight (FHB) caused by several Fusarium species is a dangerous disease of wheat and small cereals particularly in humid and sub-humid areas throughout the world. Losses due to FHB disease includes both grain yield and quality (that affect human and animal health). This investigation was aimed to identify FHB pathogens that cause blighted spikes in wheat across southwestern Ethiopia. A total of 269 single conidial isolates of Fusarium spp. were recovered from 52 FHB samples collected across southwestern Ethiopia. Based on their colony, macroscopic and microscopic features, all the isolates were identified into 9 species within the genus Fusarium. Among them, F. graminearum (29.39%) and F. culmorum (26.41%) were the dominant species followed by F. avenaceum (10.4%), F. poae (7.4%), F. ussurianum (6.7%), F. semitectum (6.3%), F. lateritium (6.0%), F. sambucinum (6.0%) and F. heterosporum (1.9%) in southwestern Ethiopia. The pathogenicity test revealed that all the 9 identified Fusarium species were caused typical FHB symptoms on spikes of a susceptible Danda’a wheat variety. Based on their AUDPC and spikelet infection severity, F. avenaceum, F. poae, F. lateritium, F. culmorum, F. sambucinum, F. heterosporum, and F. graminearum were more aggressive ones that produced higher AUDPC ranging from 546.8 to 1067.2 and higher spikelet infection severity ranging from 57.8% to 100%.