Distribution and Importance of Common Rust of Maize (Puccinia sorghi Schw.) in Hararghe Highlands, Eastern Ethiopia

Ecology; Epidemiology; Eastern Hararghe Zone; Incidence; Prevalence; Severity; Western Hararghe Zone


November 22, 2019


Maize is an important staple crop in Ethiopia. However, its production is threatened by a
number of diseases among which common rust caused by Puccinia sorghi, is the most destructive foliar
disease of the crop in the country. Data are useful to gain insight into the occurrence, distribution,
relative importance of plant diseases and the association of these diseases with cropping systems,
environmental factors and cultural practices. Therefore, field surveys were conducted during 2013 and
2014 main cropping seasons in Hararghe highlands, Ethiopia to investigate the prevalence, intensity
and importance of common rust of maize. In both years, a total of 230 maize fields were surveyed in
eastern and western Hararghe zones. In order to incorporate different altitudinal ranges and analyze
the survey data, a three-stage nested design was used. Among the surveyed maize fields, 85% of them
were infested with the disease. The mean disease incidence in two years ranged from 75% in the
eastern Hararghe to 100% in the western Hararghe zone and the severity ranged from 25% to 65%,
respectively. Combined analysis over the years also showed that the mean incidence and severity of
common rust of maize were significantly associated with the zones (χ2=15, df=1, P=0.0001). The
highest mean common rust incidence (95%) and severity (55%) were recorded for Boke, Chiro, Oda
Bultum and Tullo districts in the western Hararghe zone whilst Deder, Chelenko, Haramaya and
Kombolcha districts of the eastern Hararghe zone had the lowest mean incidence (45%) and severity
(25%) scores, respectively. Higher epidemic frequency of the disease was also associated with
intermediate and humid areas (Tullo, Boke and Oda Bultum districts) (χ2=30, df=7, P=0.0001). The
prevalence, intensity, and importance of the disease was also correlated with cropping systems,
altitude, weather variables and varieties used during the survey time (r=0.55; r=0.45; r=0.25 and
r=0.50), respectively. It is, thus, concluded, that common rust (Puccinia sorghi Schw.) is the most widely
distributed and important foliar disease of maize in Hararghe highlands.