Ginger bacterial wilt is the most destructive disease that causes qualitative and quantitative rhizome yield losses in Ethiopia. Field studies were conducted to assess yield loss caused by bacterial wilt of ginger in different wilt management systems at Teppi and Jimma, Ethiopia, during 2017. Management systems were host resistance (Boziab and Local) and cultural practices (lemon grass, potassium fertilizer and soil solarization), which were applied as sole and in different levels of integrations. The experiments were factorial arranged in a randomized complete block design with three replications. Disease, growth, yield and yield-related data were collected from central rows of each experimental plot. Data were subjected to analysis of variance using linear general model (GLM) procedure of SAS version 9.3. Mean separation was made using least significant difference test. Correlation among parameters and linear regression of rhizome yield versus final wilt incidence were computed using Minitab 14 statistical package. Analysis of variance indicated that variety, cultural practices and variety × cultural practice interaction effects significantly reduced wilt incidence and increased rhizome yield and its components. Variety Boziab recorded relatively more yield and yield components than the Local variety. Rhizome yield gains of about 51.4% in Local and 51.9% in Boziab at Teppi and 39.4% in Local and 49.1% in Boziab at Jimma were obtained due to integrated application of lemon grass with soil solarization and soil fertilization. The mean relative yield loss calculated for control plots due to bacterial wilt ranged from 51.4 to 51.9% at Teppi and 39.4 to 49.1% at Jimma. The lowest relative yield loss was computed from plots treated with either lemon grass with soil fertilization and solarization or lemon grass with soil fertilization. Final wilt incidence was inversely and highly significantly (P ≤ 0.001) correlated (r = − 0.90** and − 0.88**) with rhizome yield of Boziab and Local, respectively, at Teppi. The slope of the regression line also estimated that for each unit increase in percent of final mean wilt incidence, there was a rhizome yield reduction of 0.18 t ha−1 for Boziab and 0.19 t ha−1 for Local variety at Teppi. Similar trends were observed at Jimma. Moreover, the most integrated treatment provided higher net benefit with optimum marginal rate of return than others. The overall results indicated that integration of host resistance with cultural practices reduces yield loss, improves ginger productivity and significantly reduces bacterial wilt epidemics, and thus, it is recommended in the study areas and other related agroecologies.

Common bean is the most important pulse crops worldwide and in Ethiopia for its multipurpose uses. However, common bean production and productivity is mainly constrained by common bacterial blight (CBB) and angular leaf spot (ALS) diseases. Identifying and using resistant common bean genotypes is the best option to reduce the impact of such bacterial and fungal diseases. Field experiments were carried out to evaluate the genetic resistance of 25 common bean genotypes as treatments to CBB and ALS diseases, and agronomic performances at Haramaya and Melkassa, Ethiopia, during the 2019 and 2020 main cropping seasons. The treatments were arranged in a 5 × 5 triple lattice design with three replications. Data on disease intensity, growth, grain yield and yield components were recorded. Analysis of variance indicated significant (p < 0.0001) variations existed among the genotypes for diseases intensity, grain yield and yield components. Eight genotypes, namely DAB-388, DAB-478, DRKDDRB-70, DRKDDRB-81, NUA-225, NUA-517, NUA-536 and NUA-577 attained relatively low disease severity, AUDPC and disease progress rate next to the checks Zoasho (DAB-96) and Gorossa (Biofort large seed-5) to both common bean diseases regardless of locations and seasons. The genotype DAB-525 showed a moderately resistant reaction to both CBB and ALS, and the other genotypes demonstrated variable disease resistance reactions at both locations and in the two cropping years. Similarly, genotypes DAB-388, NUA-225, NUA-517, and NUA-577 relatively executed well for grain yield and yield components at both experimental fields in the 2019 and 2020 main cropping seasons. Disease severity and grain yield variably and negatively associated with reaction groups of genotypes evaluated for reaction CBB and ALS diseases. In the study, resistance to CBB and ALS diseases and good agronomic performing common bean genotypes were identified which could be important for smallholder and commercial bean production in the study area and other similar agro-ecologies in Ethiopia. It is suggested that a large number of common bean accessions should be evaluated in CBB and ALS hot spot agro-ecologies of Ethiopia for more sources of resistance and better agronomic advantages.

Sorghum is an important stable food crop in Ethiopia. However, production of the crop is adversely affected by biotic and abiotic constraints among which sorghum anthracnose (Colletotrichum sublineolum) is the major one. A field survey was conducted to determine the distribution and association of sorghum anthracnose with biophysical factors in eastern Ethiopia. A total of 125 fields were assessed in five districts and results revealed that all the surveyed fields were infected with anthracnose. However, significant variations observed in anthracnose intensity across the surveyed districts. Logistic regression was used to analyse the association of sorghum anthracnose with independent variables. High (≥ 60%) disease severity was highly associated with districts Girawa, Tullo and Haramaya, sole cropping system, early sowing date and continuous growing of sorghum. Lower anthracnose severity had a high probability of association with Babile district, residue removal, flowering growth stage, weed control, and rotation of different crops in the field. High distribution of sorghum anthracnose in the study areas requires effective and feasible management options to be developed.

Field surveys were conducted to determine the spatiotemporal distribution and the association of disease intensity with cropping systems and other environmental factors in Southern Ethiopia during 2016 and 2017. In both years, a total of 190 bean fields were surveyed in five districts, and common bacterial blight (CBB) was 100% prevalent. But disease incidence and severity varied among districts and between cropping years. Bean planting in Arbaminch suffered from 31% to 38%, 6–13%, 12–17% and 8–12% higher CBB severity than bean cultivation in Burjdi, Mihirab Abaya, Demba Gofa and Konso districts, respectively. The associations of disease parameters with independent factors were assessed using the logistic regression analyses. District, cropping year, altitude, land preparation, cropping system, fertiliser application, planting date, growth stage and weed infestation were associated with both disease incidence and severity with variable levels of significance. Common bean genotype was also significantly (P < .005) associated with disease severity in a multiple variable model. Concerning incidence, variable associations were demonstrated by the model. These results indicate that CBB is severe and highly prevalent in Southern Ethiopia. Therefore, efforts should be geared towards crop residue management, optimal tillage and fertiliser application, weeding, clean seed source and early planting approach to manage the disease.

Drought and salinity are environmental factors that negatively impact crop productivity in arid and semi-arid climates. Plant growth promoting rhizobia (PGPR) can help mitigate the harmful effects of drought and salinity on plant growth and productivity. This systematic review aims to summarize studies on PGPR and their mechanisms for reducing the impacts of drought and salinity, as well as to explore the effects of PGPR on different crops to improve agronomic indicators focusing on recent findings. Search was performed on PubMed, Web of Sciences and Google Scholar for papers published from 2013 to 2022. A total of 174 papers were analyzed in this review. The results showed that the PGPRs were found to increase the activity of antioxidant enzymes and stimulate plant growth under adverse conditions. The PGPRs also reduced electrolyte leakage and malondialdehyde contents, while increasing exopolysaccharide, chlorophyll, and relative water contents, for mitigating both drought and salinity stresses. PGPR strains are effective in increasing root and shoot length, root and shoot dry weight, leaf area, and leaf content. Most of the studies regarding the applications of PGPRs to enhance abiotic stress tolerance in crops were conducted under laboratory and/or greenhouse conditions, with Asia having the highest number of publications on cereals. This review shows the potential for PGPR to manage soil salinity and drought across diverse crops and ecologies. Studies on the roles of PGPRs for crop production at the field level to achieve large-scale adoption with agronomic and economic improvements are recommended.