Distribution, Intensity, and Morphological Variability of Wheat Blotch (Septoria Tritici) in Central-South-Eastern of Oromia, Ethiopia

In Ethiopia, studies of the wheat Septoria Tritici Blotch (STB) status at a different location, on agronomic practice, and pathogen variability are greatly lost. Therefore, this study was intended to assess the distribution and intensity of the STB, as well as to study the morphological variability of isolates. Zones and districts were selected purposively whereas kebeles by systematic sampling method in central-southeastern of Oromia. Mean comparison of the fixed effects was analyzed by using LSD tests in GLM. The variability of isolates was identified by their colony texture, forms, and colors. The association between disease intensity and independent variable were analyzed by Pearson correlation and its magnitudes were predicted by multiple regressions. A total of 108 fields were assessed and % prevalence of zones (88.9%-100%) and districts (77.8-100%) was documented. The STB intensity of the districts was not significantly different (p<0.05) however; severity of the zones was highly different (p<0.01). The correlation between weed infestation (r=0.78 and r=0.2) and growth stages (r=0.72 and r=0.36) was positive but the plowing frequency (r=-0.77 and r= -0.43) was negative with incidence and severity respectively. Forty-three isolates are grouped into four colors, three textures, and growth form. The current study areas are more favorable for the STB epidemics in which it should be targeted areas for integrated management. Our findings indicate that proper weed management, soil tillage, and crop rotation are interventions that can reduce the impact of wheat STB.