Economic importance of wattle rust (Uromycladium acaciae) disease on Acacia mearnsii in Fagita Lekoma, North-Western highlands of Ethiopia.

Acacia mearnsii-based rotational crop production system dominated North-Western highlands of Ethiopia, over the last two decades. The forest cover of Fagita Lekoma district, Ethiopia reached 68 % by 2021 because of A. mearnsii expansion. However, the production is now threatened by Uromycladium acaciae disease. This study examines the economic importance of U. acaciae disease in the district. Ten woodlots for two age classes were randomly selected with five replications. Two age classes were considered, as charcoal was produced from these ages, and only 4.5- and 5.5-year-old woodlots were found during data collection. To determine the growth performance and productivity of A. mearnsii post-disease occurrence, all trees (68–112) within 0.01-ha circular plots were recorded. Household surveys and field observation were led to comprehend inventory data. The economic loss was determined in terms of the growth loss of the trees. A T-test was used to determine the difference between the growth and productivity of A. mearnsii pre- and post-disease occurrence. Plantations of both age classes have significantly shown height, diameter, and volume losses following Uromycladium acaciae disease spread, particularly for those of younger counterparts. Financial losses were estimated at 7558.54 USD and 9514.35 USD per round for each age class. The district's overall forest cover and the area of A. mearnsii plantations have decreased by 3.9 % and 15.2 %, respectively, since 2020. The study urges management improvements and consideration of alternative non-target tree species to mitigate the disease's environmental impact.