Abstract

An assessment was done during the long and short rainy cropping seasons of 2010/2011 across different agro-climatic zones (ACZs) with the objective of determining the distribution, species composition and damage levels of important stem borer species in North-eastern Ethiopia. Data were collected from 21 localities of six districts, four fields in each locality, and a total of 84 fields were assessed. Busseola fusca composed of 16 to 100% of the population of stem borer species and caused damage levels of 3 to 60% in South Wollo zone at the elevation ranging from 1750 to 2338 m. Moreover, Chilo partellus is composed of 7 to 100% of the population of stem borer species and cause a damage of 1 to 100% in the same zone at the elevation range of 1492 to 2084 m. Similarly, in North Wollo zone, B. fusca shared 69 to 88% of the total population of stem borer species and cause damage levels of 5 to 53% of the elevation ranging from 1850 to 2044 m, while C. partellus composed of 12 to 31% and caused damage of 2 to 26%. In the Oromia administrative zone, which falls at the elevation of 1400 to 1669 m, 100% of the stem borer population was C. partellus and caused a damage level of 84 to 99%. The result indicates that C. partellus widened its distribution and extent of damage from the previous report of 1900 up to 2044 m. The two stem borers were found in elevation ranging from 1750 to 2044 m but their level of distribution, compositions and damage varied between elevations. Conclusively, C. partellus widened its distribution and might have replaced the indigenous species, because it was recorded as up to 2044 m, which was not reported in the previous decades.

Key words: Stemborers, elevation, agro-ecology, composition.