Association of Faba Bean Rust ( Uromyces viciae-fabae ) with Environmental Factors and Cultural Practices in the Hararghe Highlands, Eastern Ethiopia

Disease survey was conducted in Hararghe highlands of Ethiopia during the 2009 cropping season to determine the incidence and severity of faba bean rust (Uromyces viciae-fabae) in major growing districts of Hararghe highlands, and its association with environmental factors and cultural practices. A total of 90 faba bean fields were surveyed in six districts. Sample plants were systematically selected in an “X” fashion. In each field, 10 plants were sampled for disease assessment. During the survey, altitude, type of cropping system, weed management practices, crop growth stage, previous crop in the field and sowing date were recorded. Significant differences among locations were indicated with respect to altitude, sowing date, crop growth stage and field management practices. The mean incidence of the disease varied from 44.6% in Bedeno to 98% in Tullo, while severity of the disease varied from 12.7% in Bedeno to 65% in Gorogutu and Kurfachale districts. Logistic regression analysis for the association of rust incidence and severity with environmental factors and cultural practices as independent variables showed rust incidence below 80% had a high probability of association with Deder district, areas with altitude above 2450 m.a.s.l. and when faba bean was planted after July 25. Rust incidence above 80% had a high probability of association with Gorogutu, Kurfachale, Tullo districts; altitudes below 2450 masl, and when faba bean was planted from the end of June up to July 25. Similarly, disease severity below 40% had a high probability of association with Bedeno district, flowering growth stage, altitude above 2450 m.a.s.l., and when weeds were managed properly. Disease severity greater than 40% had a high probability of association with Gorogutu, Kurfachale, Tullo, Deder and Metta districts, altitudes below 2450 m.a.s.l., podding and late podding growth stages, and where poor weed management was practiced. The survey revealed high occurrence and distribution of faba bean rust in the study area and the need for effective and feasible management options to be developed. Keywords : Disease Incidence; Disease Severity; Faba Bean Rust; Uromyces viciae-fabae; Weed Management