Analysis of Factors Influencing the Distribution and Epidemics of Finger Millet Blast (Magnaporthe grisea) in Northwestern Ethiopia

Head blast, caused by Magnaporthe grisea, is one of the most widespread and important finger millet diseases in Northwestern Ethiopia. A survey was conducted in Northwestern Ethiopia in the 2020 and 2021 cropping seasons to assess the distribution and association of biophysical factors with finger millet head blast epidemics. A total of 256 finger millet fields in four major growing district were surveyed, and altitudinal ranges, variety grown, land preparation, sowing date, fertilizer application, weed management, and previous crops grown were recorded, along with incidence and severity data. Mean incidence varied from 30.8% and 37.6% in Dera to 58.8% and 56.9% in South Achefer district, while disease severity varied from 30.1% and 44.8% in Dera to 54.7% and 52.5% in South Achefer district, in 2020 and 2021, respectively. The associations between disease parameters and biophysical factors were assessed using a logistic regression model. Finger millet head blast incidence >45% had high probability of association with altitude ranging 1,950-2,050 m, Deke local variety, land preparation with <5 times ploughing, early June 28, and N-fertilizer above recommended rate in the reduced regression model. Disease severity greater than 45% also had a high probability of association with Deke local variety, early June 28, and N-fertilizer application. Therefore, the study suggested that selecting the optimal planting time and disease-resistant varieties of finger millet, along with integrated management practices could be crucial for enhancing crop resilience and yield, and significantly contribute to food security and sustainable farming in diverse agro-ecological zones.