Epidemiological study of small ruminant mange mites in three agro-ecological zones of Wolaita, Southern Ethiopia

An epidemiological study of small ruminant mange mites was conducted in three selected agro-ecological zones of Wolaita, Southern Ethiopia, from November 2007 to April 2008. A total of 352 sheep and 376 goats were examined for mange mites infestation, of which 7 (1.98%) and 22 (5.85%) sheep and goats were found positive respectively. The genuses of mange mites identified with this study were Demodex (1.23%) and Sarcoptes (2.61%) of these the genus Sarcoptes was more prevalent in the study area. The prevalence of mange mites was significantly higher in goats than in sheep (F=7.141, P=0.008). But age (X2 =0.108, P=0.743) and sex (X2 =0.007, P=0.79) of the host animals not affected the prevalence of mange mite (There was higher infestation of small ruminant in the lowland area (F=7.463, P=0.006). Keywords: small ruminant, mange mite, Agro-ecolog

Identification of the sex pheromone of the tree infesting Cossid Moth Coryphodema tristis (Lepidoptera: Cossidae)

The cossid moth (Coryphodema tristis) has a broad range of native tree hosts in South Africa. The moth recently moved into non-native Eucalyptus plantations in South Africa, on which it now causes significant damage. Here we investigate the chemicals involved in pheromone communication between the sexes of this moth in order to better understand its ecology, and with a view to potentially develop management tools for it. In particular, we characterize female gland extracts and headspace samples through coupled gas chromatography electro-antennographic detection (GC-EAD) and two dimensional gas chromatography mass spectrometry (GCxGC-MS). Tentative identities of the potential pheromone compounds were confirmed by comparing both retention time and mass spectra with authentic standards. Two electrophysiologically active pheromone compounds, tetradecyl acetate (14:OAc) and Z9-tetradecenyl acetate (Z9-14:OAc) were identified from pheromone gland extracts, and an additional compound (Z9-14:OH) from headspace samples. We further determined dose response curves for the identified compounds and six other structurally similar compounds that are common to the order Cossidae. Male antennae showed superior sensitivity toward Z9-14:OAc, Z7-tetradecenyl acetate (Z7-14:OAc), E9-tetradecenyl acetate (E9-14:OAc), Z9-tetradecenol (Z9-14:OH) and Z9-tetradecenal (Z9-14:Ald) when compared to female antennae. While we could show electrophysiological responses to single pheromone compounds, behavioral attraction of males was dependent on the synergistic effect of at least two of these compounds. Signal specificity is shown to be gained through pheromone blends. A field trial showed that a significant number of males were caught only in traps baited with a combination of Z9-14:OAc (circa 95 of the ratio) and Z9-14:OH. Addition of 14:OAc to this mixture also improved the number of males caught, although not significantly. This study represents a major step towards developing a useful attractant to be used in management tools for C. tristis and contributes to the understanding of chemical communication and biology of this group of insects

A common mechanism for efficient N 2 O reduction in diverse isolates of nodule‐forming bradyrhizobia

Bradyrhizobia are abundant soil bacteria, which can form nitrogen‐fixing symbioses with leguminous plants, including important crops such as soybean, cowpea and peanut. Many bradyrhizobia can denitrify, but studies have hitherto focused on a few model organisms. We screened 39 diverse Bradyrhizobium strains, isolated from legume nodules. Half of them were unable to reduce N2O, making them sources of this greenhouse gas. Most others could denitrify NO3‐ to N2. Time‐resolved gas kinetics and transcription analyses during transition to anaerobic respiration revealed a common regulation of nirK, norCB and nosZ (encoding NO2‐, NO and N2O reductases), and differing regulation of napAB (encoding periplasmic NO3‐ reductase). A prominent feature in all N2‐producing strains was a virtually complete hampering of NO3‐ reduction in presence of N2O. In‐depth analyses suggest that this was due to a competition between electron transport pathways, strongly favouring N2O over NO3‐ reduction. In a natural context, bacteria with this feature would preferentially reduce available N2O, produced by themselves or other soil bacteria, making them powerful sinks for this greenhouse gas. One way to augment such populations in agricultural soils is to develop inoculants for legume crops with dual capabilities of efficient N2‐fixation and efficient N2O reduction

Breeding Progress for Grain Yield and Yield Related Characters of Kabuli Chickpea (Cicer arietinum L.) in Ethiopia Using Regression Analysis

The genetic progress in seed yield and yield related characters of 10 kabuli chickpea varieties released by the Ethiopian Chickpea Crop Improvement Program from 1974 to 2017 was assessed during the main cropping season. The varieties were evaluated in the Randomized Complete Block design at Debrezeit Agricultural Research Center experimental research farm. The overall increase in seed yield over the local check, DZ-10-4, was estimated to be 739 kg/ha (38.9%). On station grain yield increased from 1900 to 3250 kg/ha during the last 43 years and the overall increase in seed yield of the Arerti variety over the oldest variety DZ-10-4 was estimated to be 1350 kg/ha or 71.1%. Based on the regression analysis, the estimated average annual rate of increase in grain yield potential was 10.87kg/ha/year with an annual relative genetic change of 0.57%/year. Genotypic change was an important source for increased grain yield potential during the studied period. Positive genetic gains were observed for the yield traits (grain yield and yield components). The average cumulative gains over 43 years of breeding was, therefore, 445.67 kg (23.37%) for seed yield, and 30.26 g for hundred seeds weight (297.7%). Hundred seed weight revealed the most dramatic response to breeding for the last 43 years. It is, therefore, strategically advisable that breeding efforts in the future should give due attention to yield related traits of kabuli chickpea varieties

Longitudinal river zonation in the tropics: examples of fish and caddisflies from endorheic Awash river, Ethiopia

Primary Research PaperSpecific concepts of fluvial ecology are well studied in riverine ecosystems of the temperate zone but poorly investigated in the Afrotropical region. Hence, we examined the longitudinal zonation of fish and adult caddisfly (Trichoptera) assemblages in the endorheic Awash River (1,250 km in length), Ethiopia. We expected that species assemblages are structured along environmental gradients, reflecting the pattern of large-scale freshwater ecoregions. We applied multivariate statistical methods to test for differences in spatial species assemblage structure and identified characteristic taxa of the observed biocoenoses by indicator species analyses. Fish and caddisfly assemblages were clustered into highland and lowland communities, following the freshwater ecoregions, but separated by an ecotone with highest biodiversity. Moreover, the caddisfly results suggest separating the heterogeneous highlands into a forested and a deforested zone. Surprisingly, the Awash drainage is rather species-poor: only 11 fish (1 endemic, 2 introduced) and 28 caddisfly species (8 new records for Ethiopia) were recorded from the mainstem and its major tributaries. Nevertheless, specialized species characterize the highland forests, whereas the lowlands primarily host geographically widely distributed species. This study showed that a combined approach of fish and caddisflies is a suitable method for assessing regional characteristics of fluvial ecosystems in the tropicsinfo:eu-repo/semantics/publishedVersio

Landscape-based nutrient application in wheat and teff mixed farming systems of Ethiopia: farmer and extension agent demand driven approach

Introduction: Adapting fertilizer use is crucial if smallholder agroecosystems are to attain the sustainable development goals of zero hunger and agroecosystem resilience. Poor soil health and nutrient variability characterize the smallholder farming systems. However, the current research at the field scale does not account for nutrient variability across landscape positions, posing significant challenges for targeted nutrient management interventions. The purpose of this research was to create a demand-driven and co-development approach for diagnosing farmer nutrient management practices and determining landscape-specific (hillslope, mid-slope, and foot slope) fertilizer applications for teff and wheat. Method: A landscape segmentation approach was aimed to address gaps in farm-scale nutrient management research as well as the limitations of blanket recommendations to meet local nutrient requirements. This approach incorporates the concept of interconnected socio-technical systems as well as the concepts and procedures of co-development. A smart mobile app was used by extension agents to generate crop-specific decision rules at the landscape scale and forward the specific fertilizer applications to target farmers through SMS messages or print formats. Results and discussion: The findings reveal that farmers apply more fertilizer to hillslopes and less to mid- and foot slopes. However, landscape-specific fertilizer application guided by crop-specific decision rules via mobile applications resulted in much higher yield improvements, 23% and 56% at foot slopes and 21% and 6.5% at mid slopes for wheat and teff, respectively. The optimized net benefit per hectare increase over the current extension recommendation was $176 and$333 at foot slopes and $159 and$64 at mid slopes for wheat and teff (average of $90 and$107 for wheat and teff), respectively. The results of the net benefit-to-cost ratio (BCR) demonstrated that applying landscape-targeted fertilizer resulted in an optimum return on investment ($10.0 net profit per$1.0 investment) while also enhancing nutrient use efficiency across the three landscape positions. Farmers are now cognizant of the need to reduce fertilizer rates on hillslopes while increasing them on parcels at mid- and foot-slope landscapes, which have higher responses and profits. As a result, applying digital advisory to optimize landscape-targeted fertilizer management gives agronomic, economic, and environmental benefits. The outcomes results of the innovation also contribute to overcoming site-specific yield gaps and low nutrient use efficiency, they have the potential to be scaled if complementing innovations and scaling factors are integrated

Bovine trypanosomosis and gastrointestinal helminthosis in settlement villages of Bedele district, South-western Ethiopia

This cross-sectional study was carried out from October 2011 to March 2012 to assess the concurrent infections of bovine trypanosomosis with gastrointestinal (GI) helminthes in Peasant Associations of Bedele district settlement areas located in Illubabor Zone, Southwestern part of Ethiopia. A total of 500 randomly selected cattle were examined using Buffy Coat Technique and coprological examinations. Faecal examination was done by sedimentation and flotation techniques following the standard procedures to identify eggs of parasitic helminthes. Those faecal samples that were positive for flotation technique were subjected to eggs per gram (EPG) count using Mc Master egg counting technique and the degree of infestation was categorized as light, moderate and severe. Out of total cattle examined, 21(4.2%) were positive for Trypanosoma congolense and 321(64.2%) were found to harbor one or more gastrointestinal helminthes infection. Helminthes identified were Fasciola species (51.4%), paramphistomum species (18.7%), the protozoan Eimeria species (6.2%), Trichuris species (6.85%), Trichostrongyles (11 %) and mixed infections (6%). The overall mean PCV value recorded was 26.7±3.9 and it was 26.8±3.9 in trypanosome negative animals and 22.9±3.3 in trypanosome positive animals. The overall mean EPG recorded was 172±99.6. Among 21 cattle found positive for T. congolense, 18 (85.7%) were concurrently infected with (GI) helminthes particularly Fasciolosis (38.1%) and statistically there was significant association (P < 0.05) between trypanososmosis and GI helminthes infection. Age and sex of sampled cattle were not found to influence GI helminthes prevalence (p>0.05). Infection with T. congolense and Fasciola species is the most prevalent form of co-infection in cattle within study areas. In conclusion, any attempts to control or prevent trypanosomosis or GI helminthes infection through different management approaches, need to address the possibility of concurrent infections especially in trypanosomosis endemic areas to save the losses in advance.Key words: Bedele, Cattle, Concurrent, Ethiopia, GI helminthes, Trypanosomosi