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Plantation forests are established by planting Eucalyptus tree species to provide timber and pulp for the construction industries and to meet the energy needs in Ethiopia. Besides the extensive Eucalyptus plantations in the country, fungal pathogen-related diseases are the main challenges to successful production and management. The disease survey was conducted in the Eucalyptus growing areas of Ethiopia during 2019/2020 and 2020/2021. The objective of this research was to assess the diseases associated with Eucalyptus plant species and identify the causal fungal species. Plants of E. camaldulensis were the dominant species in the survey fields and were severely associated with stem and branch canker diseases. Diseased samples were collected and fungal species were identified as Didymellaceae according to culture morphology and affirmed by internal transcribed spacer sequence analysis. In phylogeny, isolates in the study and a reference strain formed supportive monophyletic clades with strong 90% and 95% support with Didymella coffeae-arabicae and Didymella pinodella respectively. Pathogenicity tests revealed that Didymellaceae could infect E. camaldulensis. The findings are the first reports of Eucalyptus stem canker disease caused by Didymellaceae in Ethiopia.

Field surveys of E. camaldulensis diseases were conducted during 2019/20 and 2020/21 in Ethiopia. This species was found the most commonly planted in the surveyed fields and were showing stem canker diseases. Sampling was done from diseased stem and branches with clear symptoms. The morphological as well as PCR assay of the ITS1 and ITS2 loci were performed to identify the fungal pathogens. Lasiodiplodia theobromae and Didymella pinodella were the identified fungi. Four nationally licensed fungicides, Vitra (copper hydroxide), Ridomil gold (Metalaxyl-M + mancozeb), Liveshow (Pyraclostrobin + Epoxiconazole), and Sabozeb (Mancozeb) were evaluated for their in vitro efficacy against these fungi at concentrations of 500, 1000, 1500 and 2000 ppm for the management trial. Vitra and Liveshow were found to be the most effective fungicides at 2000 ppm for the control and treatment of Eucalyptus camaldulensis stem canker diseases. The findings from this research will provide foundation for future studies as this is the first report for the management of this Eucalyptus tree disease in Ethiopia. [ABSTRACT FROM AUTHOR]