author(s)
Misrak Urge, Mulugeta Negeri, Girma Demissie and Thangavel Selvaraj

abstract
Assessment of major field insect pest species and their losses in maize (Zea mays L.) crops production was conducted during the crop seasons of 20l8 to 2019 at Chiro and Darolebu districts of West Hararghe Zone, Oromia Region, Ethiopia. Sampling technique was purposive for identifying districts that had high maize crops production potential from the zone. From each district, three localities were selected purposively. During the study period, three economically important insect pests were listed out from maize cultivated fields. Among the insect pests, American Fall Army Worm (Spodoptera frugiperda), Maize Stem Borer (Busseola fusca) and African Ball Worm (Helicoverpa armigera) were major pests recorded on maize crop fields. Among the insect pests the first rank priority in maize cultivated fields at both districts, S. frugiperda were more abundant and dominant followed by B. fusca and lastly H. armigera. The respondents were estimated as yield losses of 10-30% by S. frugiperda, 3-15% by B. fusca, 3-15% by H. armigera on maize crop fields at Darolebu and Chiro districts, respectively. The greatest yield loss caused by insect pests was 10-30% by AFAW for maize crop at Darolebu and Chiro districts. The training should be given for both farmers and extension workers on insect pests identification and their management, so they should be produced proper operation to early protect their maize crops from insect pests to reduce the yield losses.