DISEASE INCIDENCE, INSECT PEST PREVALENCE, WEED ABUNDANCE, AND DIVERSITY IN SESAME (Sesamum indicum L.) FIELDS OF KAMASHI AND ASSOSA ZONES OF BENISHANGUL GUMUZ REGION, ETHIOPIA

Abstract

Sesame, a vital global oilseed crop, confronts persistent challenges from diseases and pests, particularly in high rainfall areas like Northwestern Ethiopia, where yield loss is imminent. Information regarding the primary pests affecting sesame within specific agroecological contexts is essential for devising effective pest management strategies. However, limited information exists on major sesame pests in the Assosa and Kamashi zones of the Benishangul Gumuz region, Ethiopia. Hence, a survey was conducted during the 2017/2018 main cropping season in Assosa and Kamashi zones to identify major diseases, insect pests, and weed species affecting sesame, as well as to determine the incidence and severity of diseases, prevalence of insect pests, and the abundance and diversity of weed species in the area. The survey uncovered bacterial blight, Cercospora leaf spot, and phyllody as the predominant diseases affecting sesame crops in the regions surveyed. Bacterial blight exhibited the highest disease incidence at 98.84%, followed by Cercospora leaf spot at 73.25%, with phyllody recorded at a lower incidence of 11.29%. Disease severity assessment indicated bacterial blight had a mean severity of 49.88%, while Cercospora leaf spot recorded 36.44%. Additionally, aphids, gall midge, and webworms were found as primary insect pests, with aphids and gall midge having mean incidences of 13.76% and mean prevalence of 45.61% and 8.77%, respectively. In contrast, webworm had a low mean incidence (1.00%) and prevalence (1.75%). The survey also highlighted the diversity of weed species, with ten identified as broadleaf. These broadleaf weeds, especially fast-growing ones, compete significantly with sesame, suggesting early hand weeding, particularly in regions like Benishangul Gumuz with high rainfall. Overall, the findings underscore the necessity for customized pest management strategies based on agroecological conditions and pest dynamics.