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Studies of the wheat Zymoseptoria tritici blotch (ZTB) status in different locations, on agronomic practice, and pathogen variability has not yet been studied in Ethiopia. As a result, the goal of this study was to determine ZTB's distribution and intensity, as well as the morphological variability of isolates. In Oromia's central-southeastern region, zones and districts were purposefully chosen, whereas kebeles were determined via a systematic sampling procedure. In a generalized linear model (GLM), the mean comparison of fixed effects was examined using least significant difference (LSD) tests. Colony texture, shapes, and colors were used to identify isolate variability. Pearson correlation was used to examine the relationship between disease intensity and the independent variable, and multiple regression analysis was used to estimate the magnitudes of the association. A total of 108 fields were examined, with the percent occurrence of zones (88.9 to 100%) and districts (77.8 to 100%) recorded. ZTB intensity was not significantly different across districts (p 0.05) while severity was significantly different across zones (p 0.01). Weed infestation (r = 0.78 and r = 0.20) and growth phases (r = 0.72 and r = 0.36) had a positive correlation, although plowing frequency (r = -0.77 and r = -0.43) had a negative correlation with incidence and severity. There are 43 isolates classified into four colors, three textures, and three growth forms. The ZTB epidemics in current research areas are need more consideration and they should be prioritized for integrated management. Our data suggest that weed control, soil tillage, and crop rotation are all effective ways to mitigate the effects of wheat ZTB.

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Wheat leaf blotch caused by Zymoseptoria tritici (Zt) is a fungal disease that poses a severe danger to wheat production worldwide. Knowing the virulence diversity of this pathogen is crucial for taking effective control measures. However, there have been a few studies on Ethiopia pathogenic variability and pathotypes based on physiological specialization. Therefore, the goal of this study was to look at the virulence, spectrum, and population variability of Zt isolates. In a completely randomized design, 43 isolates in three replications were tested for their virulence and pathotypes against 7 wheat differential lines. The least significant difference method was used to identify specific virulence; whereas, pathotypes, principal components, and cluster analysis were used to study the pathogenic diversity. Then, virulence assay detected 41 differential lines specific virulence and 220 differential lines specific avirulence, among all (n = 301) interactions based on pycnidia parameter. Some of the isolates showed a considerable virulence spectrum on 4 (57.1%) and 5 (71.4%) differential lines based on pycnidia and leaf necrosis respectively; but, most of them were partial virulent on the differential lines. Based on pycnidia parameter: EtA-11, EtSh-1, EtSh-2, EtSh-4, and EtA-19 isolates expressed the virulent reaction on 3–4 differential lines; hence, useful for germplasm screening. Over, from this parameter, 25 pathotypes were ensued in which indicated 58.1% pathogenic diversity; moreover, the principal component analaysis detected 62.2% pathogenic diversity of Ethiopian isolates. Therefore, further virulence variability investigations employing isolates*wheat species specificity and molecular analysis are important. Wheat breeders and wheat farmers would find the results from this study extremely useful for making informed decisions on how to manage Zt disease. Again, it is crucial to examine the virulence diversity of Zt isolates using pathotype and principal component analysis.

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