Microbiology and Plant Pathology

Wheat (Triticum aestivumL.) is the most important staple crop in temperate zones and is in increasing demand in countries undergoing urbanization and industrialization. However, its production is affected by many biotic and abiotic factors. Among biotic production constraints; wheat stem rust ( Puccinia graminis f.sp tritici) is the most important one. This study was (i) to assess the importance of wheat stem rust in North and East Shoa zones of central Ethiopia and (ii) to identify physiological races. Purposive multistage sampling was used to select major wheat growing districts and farmers associations from each zone. Wheat stem rust race identification was carried out via inoculation of isolates on susceptible line (McNair); single pustule isolation; inoculation on standard differential sets and infection type evaluation of each line fourteen days after inoculation. One hundred fifty wheat fields (75 from each zone) were assessed. Wheat stem rust was observed in 71 (94.7%) and 5...

Global food security is vulnerable due to massive growth of the human population, changes in global climate, the emergence of novel/more virulent pathogens, and demands from increasingly discerning consumers for chemical-free, sustainably produced food products. Bacterium- based biological control agents (BCAs), if used as part of an integrated management system, may satisfy the above demands. We focus on the advantages, limitations, problems, and challenges involved in such strategies.

Alternaria leaf spot of chilli caused by Alternaria alternate is an important disease affecting
chilly production areas in India. The disease is primarily controlled through the use of fungicidal
seed treatments. In this study, different fungicides viz. Captol, Captan, Ziram, Captofol, Thiram,
Indofill Z 78 and Indofill Z 45 were assessed for their ability to reduce the growth of Alternaria
alternata under laboratory conditions. Maximum inhibition (100%) was achieved by Captol and
capton followed by captofol (89.5 %) while 0.1 % dose given. This paper reports the efficacy
of fungicides that can be used under field conditions to control alternaria leaf spot in tropical
regions and demonstrates the use of a method of application that could significantly improve the
efficacy of disease control.
Keywords: fungicides efficacy; captol; captofol; Alternaria alternata.

Common bacterial blight (CBB) is the most devastating factor that affects common bean crops in all common bean growing areas. This review was to review with an objective of reviewing the biology, economic importance of CBB of common bean crop disease and its management options, with an emphasis on the future research direction and priorities. CBB disease, caused by the gram-negative bacterial pathogen Xanthomonas axonopodis pv. phaseoli (Xap) and its fuscans variant Xanthomonas fuscans subsp. fuscans (Xff) is the major bottleneck in bean production in the world as well as in Ethiopia. It is a serious bacterial disease of common bean which causes lesions on the leaves, stems, pods and seeds of the plant. The disease affects seed quality and can reduce yield by up to 45%, may be more in susceptible cultivars. CBB is very difficult to control due to seed-borne nature of the bacteria and its capacity to produce huge amounts of secondary inoculum. Since the disease is very important in c...

Grape (Vitis vinifera) usually grows well in temperate countries. Many study show that consumption of grape and various other parts of the fruit, especially the seeds, provides many health benefits. The purpose of this study was to explore the antimicrobial activity of Vitis vinifera leaf extract. Sample consisting of fresh healthy leaves that were tested for their properties to inhibit growth of four species of bacteria, namely,
Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis. Disc diffusion test method was used to determine the ability of the extract to inhibit the bacteria growth. The inhibition zones
against the tested bacteria were ranging from 23.7 to 30 mm. The highest zone of inhibition produced by hot
water extract S. aureus was (30 mm), E. faecalis (28.9 mm), E. coli was (28 mm) and P. aeruginosa (23.7mm).
The extract of Vitis vinifera leaf was found to be valuable antibacterial agent. Leaves extract was able to inhibit the growth of S. aureus, E. faecalis, E. coli and P. aeruginosa, but their inhibitory activity against P. aeruginosa was less. This study confirms that Vitis vinifera leaf extract has antimicrobial activity that could be beneficial to human health.

Material and Methods Sample collection Eight three tef seeds accessions were collected from Ethiopian biodiversity institute germplasm repository in 2017 G.C. Isolation of tef seed endophytic bacteria Collected seed samples were washed in sterile water and immersed in 70% ethanol for 3 min and followed by fresh sodium hypochlorite solution (2% NaClO) for 5 min; and then transferred to 70% ethanol (v/v) for 30 secs to remove the remaining NaClO. Finally, the seeds were

Despite the usefulness of nematicidal compounds in agricultural practices, but it cause environmentally problems, which lead to seek about safe and alternative agents as tools to be used in the plant nematodes management programs. Abamectin is one of the suggested alternative biorational tool that belongs to avermectin group, which belong to macro cyclic lactones metabolites produced by a natural fermentation of the bacterium Streptomyces avermitilis. Abamectin mixture contains more than 80% avermectin B1 a and less than 20% avermectin B1 b. Meanwhile, abamectin used as an insecticide, acaricide and nematicide on vegetables, fruits and field crops. On the other hand, neem oil is a vegetable oil pressed from the fruits and seeds of the neem tree, Azadirachta indica. The neem tree was recognized for its unique properties against insects, and in improving human health. It is grown in most tropical and subtropical areas. Its leaves, bark, and seed kernels extracts, or cake, can be utilized in phytonematodes management. Various components such as nimbin, nimbidin, azadirachtin, salannin, thionemon, and meliantriol occur in the seeds, leaves, and the bark of neem with high concentrations. The effect of neem against plant parasitic nematodes was noticed and recorded in many reports, as well as its insecticidal, fungicidal and bactericidal efficacy.

Potato is the world’s number one non-grain food commodity, with production reaching 325 million tons. Some inherent qualities give potato a competitive edge over the leading food crops. It is able to produce more protein and carbohydrates per unit area than cereals. Among all the crops grown worldwide, is known to suffer the greatest losses from disease attack. Among those diseases late blight and bacterial wilt are the most economical diseases which incurred 100% yield loss. The main Objective of this review was to understand very well the recent advances on potato late blight disease management up to gene for gene level and incorporate these recent molecular advances with the conventional one for mitigating the virulence spectrum of the pathogen. The population of P. infestans characterized using molecular markers has led to better understanding of pathogen at molecular level. Mitochondrial DNA haplotyping of P. infestans has revealed that mt Ia is displacing the other haplotypes ...

Pawpaw (Carica papaya L.) fruit production has become an integral part of daily life as a source of food, vitamins and minerals which is one of the most popular, cheapest, economically important fruit tree grown in Nigeria. The study of the fungi associated with postharvest rot of Carica papaya fruit were carried out in three different markets of Mubi North and South Local Government Area of Adamawa State (Kuturu Market, Mubi Old Market and Mubi New Market) from June to November, 2016 to test for both invitro and invivo antifungal efficacy of seed extracts of Khaya senegalensis. Sample of papaya fruits were collected, and industrial PDA was used for the isolation of the fungi pathogens. Four fungal pathogens were isolated from papaya fruits and were identified as Rhizopus stolonifer, Botryodiplodia theobromea, Aspergillus niger and Mucor spp. Control trials using seed extracts of Khaya senegalensis was conducted at six different concentration levels (0%, 20%, 40%, 60%, 80% and 100%). Incidence of rot showed that Kuturu Market had the highest with 26.77%, followed by Mubi Old Market (20.77) and then Mubi New Market (20.20). Results obtained from the control trials with seed extracts of Khaya senegalensis both invitro and invivo showed significant differences (p>0.001) and was effective in inhibiting fungal growth although with variation in their effect.

A new strain (FB01) of Tobacco curly shoot virus (TbCSV) showing curly shoot symptoms on common bean plants from Varanasi, Uttar Pradesh state of India was characterized. The analysis of the whole genome sequence and individual ORFs of this virus indicated that it is very closely related (sequence similarity of 89.1-94.5%) to the TbCSV infecting solanaceous and other weed crops in India and China. This was well supported by phylogenetic analysis with close clustering of the virus isolate with TbCSV. The absence of DNA-B and association of virus with betasatellite confirmed it as a monopartite begomovirus. The betasatellite identified here shared highest (53.9-93.9%) sequence identity with tomato leaf curl betasatellite. Further, putative recombination events were recognized within the virus sequence, suggesting that the virus is a recombinant and evolved from recombination of Tobacco curly shoot virus, Munbean yellow mosaic virus, Tomato leaf curl Jodhpur virus, Tobacco leaf curl Yunnan virus and Ageratum enation virus like ancestors. For betasatellite, the putative recombination events were recognized within the sequence, were interspecific. The new recombinant betasatellite was derived from recombination between Croton yellow vein mosaic betasatellite and Tomato yellow leaf curl China betasatellite, as the foremost parents in its evolution. The virus was transmitted by whiteflies as well as sap, and not by seed.

Viral and bacterial diseases of potato cause significant yield loss worldwide. The current data on the occurrence of these diseases in Russia do not provide comprehensive understanding of the phytosanitary situation. Diagnostic systems based on disposable stationary open qPCR micromatrices intended for the detection of eight viral and seven bacterial/oomycetal potato diseases have been used for wide-scale screening of target pathogens to estimate their occurrence in 11 regions of Russia and to assess suitability of the technology for high-throughput diagnostics under conditions of field laboratories. Analysis of 1025 leaf and 725 tuber samples confirmed the earlier reported data on the dominance of potato viruses Y, S, and M in most regions of European Russia, as well as relatively high incidences of Clavibacter michiganensis subsp. sepedonicus, Pectobacterium atrosepticum, and P. carotovorum subsp. carotovorum, and provided detailed information on the phytosanitary status of selected regions and geographical spread of individual pathogens. Information on the occurrence of mixed infections, including their composition, was the first data set of this kind for Russia. The study is the first large-scale screening of a wide range of potato pathogens conducted in network mode using unified methodology and standardized qPCR micromatrices. The data represent valuable information for plant pathologists and potato producers and indicate the high potential of the combined use of matrix PCR technology and network approaches to data collection and analysis with the view to rapidly and accurately assess the prevalence of certain pathogens, as well as the phytosanitary state of large territories.

Xanthomonas citri subsp. malvacearum causes severe qualitative and quantitative losses to farmers in cotton growing areas of the world. Timely detection of the bacterial pathogen causing blight in cotton is extremely important in developing management strategies against the disease. Bacterial isolates were extracted from cotton seeds obtained from five ginneries located in northern Nigeria. Bacterial colonies were isolated and tested for nitrate reductase activity, oxidase reaction, catalase reaction , aesculin hydrolysis, utilisation of carbon from different sources and Tween 80 hydrolysis was assessed, PCR was also carried out on the isolates. The studied bacteria from the four locations reacted positively to Tween 80 hydrolysis and catalase test. Maltose digestion was negative in all samples, hydrolysis and digestion of arabi-nose, arabitol, cellobiose, lactate and acetate were positive. They were thus identified as members of the species X. citri based on the biochemical tests run. Molecular detection using PCR positively identified the pathogen.

The effects of culture conditions at different temperature and light regimes on growth and the contents of chlorophyll-a, chlorophyll-b, total carotenoids, total protein and total free amino acids of Chlorella vulgaris were determined. The growth of C. vulgaris in terms of optical density (0.42 at 670 nm), cell count (440 x 104 cells/ml) and dry weight (30.2 mg/50 ml), and the amount of chlorophyll-a (2.16%), chlorophyll-b (0.59%) and total protein, was found higher at the temperature 25-30°C and natural day light receiving through the north facing window of the growth room. Although, the amount of total carotenoids (0.440%) and free amino acids (834 µg/gm fresh weight) were found maximum in continuous light at 30-35°C, not much differences in the amount of carotenoids (0.385%) and free amino acids (822 µg/gm fresh weight) were found at 25-30°C and natural day light. The natural day light at 25-30°C was also proved proficient, as distinct banding pattern with unique polypeptides such as 15KDa, 47KDa and 50KDa, on the other hand, 23KDa, 26KDa and 36KDa appeared in all samples, these bands were not affected by light and temperature. Our results indicate that among all five culture conditions tested, the cultures kept at north facing window receiving natural day light at temperature 25-30°C, show best growth and higher contents of biochemicals that will be beneficial to use Chlorella for high nutritive purpose.

Loop-mediated isothermal amplification assay amplifies DNA/RNA with high specificity and sensitivity. In this study, we describe an optimized reverse transcription-LAMP assay for detection of Potato Leafroll Virus. Firstly, DAS-ELISA assay was performed to detect of the virus in a collection containing 40 suspicious samples. Lastly, two samples were detected as the positive samples. Then, the positive samples were verified by RT-PCR and RT-LAMP methods. Furthermore, the results demonstrated that the RT-LAMP assay was 40 times sensitive and 4 time faster compared to RT-PCR. RT-LAMP assay was accomplished in the water bath either frees from any thermal cycler machine or sophisticated laboratories facility. Moreover, in RT-LAMP reaction the positive samples were detected through turbidity which produced by magnesium pyrophosphate. Interestingly, the application of CaCl 2 instead of MgSO 4 which create calcium pyrophosphate in reaction could significantly increase both stability and concentration of turbidity. Consequently, it could be an interesting alternative to MgSO4. Overall, the newly developed RT-LAMP assay can be a sensitive, specific and low-cost method for early detection of Potato Leafroll Virus and also other viral plant pathogens.

Ascochyta rabiei is the casual agent of blight disease of chickpea (Cicer arietinum L.). The study was aimed to assess the genetic diversity of highly aggressive Ascochyta rabiei (AR) isolates (pathotypes III and IV) from Syria and its comparison with highly aggressive isolates from Pakistan. AR isolates were characterized for pathogenicity assay and genetic variability. Previously genetic variability of AR isolates have been checked with RAPD and SSR markers, here we are reporting for the first time diversity using ten Universal rice primers (URP) derived from the repeat sequence of rice genome. URP proved very useful for the characterization of isolates and clearly differentiated Syrian pathotypes from Pakistani ones. URP can be helpful in studying the population variability from AR pathotypes worldwide.

The main concern in molecular detection of RNA viral pathogens in plants is the achievement of good quality of the extracted RNA. Various methods of isolating RNAs from both polysaccharide-rich and poor tissues and other recalcitrant plants are available. However, the use of time and reagent consuming methods and those involving hazardous chemicals is somewhat cumbersome and problematic, especially when it is not necessary for specific purposes like isolating viral RNA from tomato fruit, hence the objective of this paper. We describe an alternative, simple and rapid method for preparing viral RNA from tomato fruit without RNA extraction and purification steps, case of Pepino mosaic virus (PepMV).

Food security (a pressing issue for all nations) faces a threat due to population growth, land availability for growing crops, a changing climate (leading to increases in both abiotic and biotic stresses), heightened consumer awareness of the risks related to the use of agrichemicals, and also the reliance on depleting fossil fuel reserves for their production. Legislative changes in Europe mean that fewer agrichemicals will be available in the future for the control of crop pests and pathogens. The need for the implementation of a more sustainable
agricultural system globally, incorporating an integrated approach to disease management, has never been more urgent. To that end, the Valorizing Andean Microbial Diversity (VALORAM) project (http://valoram.ucc.ie), funded under FP7, examined the role of microbial
communities in crop production and protection to improve the sustainability, food security, environmental protection, and productivity for rural Andean farmers. During this work, microbial volatile organic compounds (mVOCs) of 27 rhizobacterial isolates were identified using gas chromatography/mass spectrometry (GC/MS), and their antifungal
activity against Rhizoctonia solani was determined in vitro and compared to the activity of a selection of pure volatile compounds. Five of these isolates, Pseudomonas palleroniana R43631, Bacillus sp. R47065, R47131, Paenibacillus sp. B3a R49541, and Bacillus simplex M3-4 R49538 trialled in the field in their respective countries of origin, i.e., Bolivia, Peru, and Ecuador, showed significant increase in the yield of potato. The strategy followed in the VALORAM project may offer a template for the future isolation and determination of putative biocontrol and plant growth-promoting agents, useful as part of a low-input integrated pest management system.

Viral and bacterial diseases of potato cause significant yield loss worldwide. The current data on the occurrence of these diseases in Russia do not provide comprehensive understanding of the phytosanitary situation. Diagnostic systems based on disposable stationary open qPCR micromatrices intended for the detection of eight viral and seven bacterial/oomycetal potato diseases have been used for wide-scale screening of target pathogens to estimate their occurrence in 11 regions of Russia and to assess suitability of the technology for high-throughput diagnostics under conditions of field laboratories. Analysis of 1025 leaf and 725 tuber samples confirmed the earlier reported data on the dominance of potato viruses Y, S, and M in most regions of European Russia, as well as relatively high incidences of Clavibacter michiganensis subsp. sepedonicus, Pectobacterium atrosepticum, and P. carotovorum subsp. carotovorum, and provided detailed information on the phytosanitary status of select...

Olive knot disease, caused by Pseudomonas savastanoi pv. savastanoi, is one of the most important biotic stress for olive cultivation in most olive cultivation areas, particularly in Mediterranean countries. It conducts to intense damage in olive groves, causing heavy production losses. Bacillus mojavensis A-BC-7, a natural colonizer of symptomless olive phylloplane, was determined as potential biocontrol agent against olive knot disease strain ITM317-Rif, a mutant strain resistant to Rifampicin (100 ppm). Bioassays on one-year-olive plants were carried out to survey the antagonism of A-BC-7 controlling knot development and pathogen populations when co-inoculated with the pathogen on stems with different ratios. Results showed that A-BC-7 was able to decrease knot weights and pathogen population size, producing less necrotic tumors. In particular, when we applied the mixture suspensions of ITM317-Rif+A-BC-7 with the ratio 1:9 that resulted of 43.11% of overgrowth inhibition at 30 days after inoculation, which increased to reach about 59% at 60 days after inoculation and then 75% at 90 days after inoculation. That may pose epidemiological consequences.

Procedure Media preparation MS Medium (Stock): Medium prepared in varying concentration of hormones. Murashige and Skoog's medium was prepared using Macronutrients Stock 1 (Table 1), Macronutrients Stock 2 (Table 2), Macronutrients Stock 3 (Table 3), Micronutrients Stock 4 (Table 4) and Vitamins (Table 5). The medium for tissue culture contained macronutrients, micronutrients and vitamins. The components of MS medium (Stock 1) are ammonium nitrate, potassium nitrate, potassium dihydrogen phosphate and magnesium sulphate. Specific amounts of each were measured and the solution was made upto 1 L using distilled water. Stock 2 contained calcium chloride. Stock 3 contained disodium salt of EDTA and ferrous sulphate hydrate. Stock 4 contained Magnesium sulphate tetrahydrate, zinc sulphate, boric acid, Potassium iodide, disodium molybdate, cuprous sulphate pentahydrate and cobalt chloride. Stock 5 contained glycine vitamins nicotinic acid, pyridoxine HCL and thiamine. Media preparation: Stock solution from 1-5 were mixed in specific amounts. 20 ml of stock Ӏ, 20 ml of stock ӀӀ, 10 ml of stock ӀӀӀ, 10 ml

Potato is the world’s number one non-grain food commodity, with production reaching 325 million tons. Some inherent qualities give potato a competitive edge over the leading food crops. It is able to produce more protein and carbohydrates per unit area than cereals. Among all the crops grown worldwide, is known to suffer the greatest losses from disease attack. Among those diseases late blight and bacterial wilt are the most economical diseases which incurred 100% yield loss. The main Objective of this review was to understand very well the recent advances on potato late blight disease management up to gene for gene level and incorporate these recent molecular advances with the conventional one for mitigating the virulence spectrum of the pathogen. The population of P. infestans characterized using molecular markers has led to better understanding of pathogen at molecular level. Mitochondrial DNA haplotyping of P. infestans has revealed that mt Ia is displacing the other haplotypes ...

Common bacterial blight (CBB), caused by Xanthomonas axonopodis pv. phaseoli Smith (Xap) and Xanthomonas axonopodis pv. phaseoli var. fuscan Burkholder (Xapf) is the most serious biotic constraint of common bean (Phaseolus vulgaris L.) production. Variables temperature and moisture are dominant climate factors that affect common bean growth as well as the development of CBB epidemics. Two sets of experiments were conducted in the Plant Pathology Laboratory of Haramaya University) to assess the effect of temperature and moisture on the resistance level of common bean in 2014 and 2015. In the first experiment, two common bean varieties (Gofta and Mexican 142) were inoculated with two bacterial strains (Xap and Xapf) and a control were incubated at four temperature levels (28°C, 30°C, 32°C and 34°C) in growth chambers. In the second experiment, three-soil moisture levels (100%, 75% and 50%) were employed to that of experiment one. The treatment combinations were arranged in factorial completely randomized design (CRD) in the growth chambers for both series of experiments. The disease rating was significantly (P<0.05) affected by common bean varieties and temperature levels at 17 days after inoculation (DAI). Higher disease rating was recorded on the variety Mexican 142 than on Gofta. The highest (1.75) mean disease rating was recorded at 28°C and the lowest (1.44) at 34°C. The mean disease ratings differed significantly among the moisture levels. The highest (2.01) mean disease rating was recorded from 75% moisture content, while the lowest (1.80) disease rating was obtained from 50% moisture content. The results of these series of experiments indicated that climate change effects above optimum level would not be favorable for CBB development in the arid and semi-arid agro ecologies unless new bacterial strains adapted to the drought tolerant common beans in the area.

A major threat for bananas and plantains production is the Panama Disease or Fusarium Wilt caused by Fusarium oxysporum f. sp. cubense. In order to characterize the causal agents of Fusarium wilt in Mexico, a sampling was performed in symptomatic plantains growing in fields of Oaxaca, a coastal southern state of Mexico. A phylogenetic analysis based on the sequences of TEF 1-α and IGS revealed that three isolates belonged to the Fusarium oxysporum species complex, while two other isolates were identified as members of the Fusarium fujikuroi species complex. Furthermore, isolates from the same complex shared the same ITS2 sequence. Inoculation using spores of each isolate on the roots of Musa sp. AAB cv. Manzano produced wilting symptoms of varying severity, suggesting that the Fusarium wilt might not be caused only by Fusarium oxysporum f. sp. cubense. PCR-based detection of Secreted in Xylem (SIX) genes showed that each Fusarium isolate harbored a unique combination of genes typically found in banana pathogens, which might cause the disease.

Root rot is an important disease of mungbean [Vigna radiata (L.) Wilczek] caused by Macrophomina phaseolina (Tassi) Goid was observed in farmers field of Rajasthan. For the integrated management of the disease, biocontrol agents, fungicides, herbal oils, plant extracts and organic manure as well as their combinations. Among the tested biocontrol agents against Macrophomina phaseolina, T. harzianum was found the most effective against the fungus under in vitro and in pots conditions followed by T. viride and T. ...

A laboratory experiment was conducted to study the efficacy of some botanicals against seed-borne fungi isolated from barley. Alternaria alternata was the most frequently isolated fungi followed by Rhizopus spp., and Mucor spp., determined by plating the seeds on both standard blotter and agar plate method. Leaf extracts of five plants viz., Eucalyptus globulus, Calotropis procera, Melia azedarach, Datura stramonium and Acalypha indica @ 5%, 10% and 20% concentration were evaluated against A. alternata. The results revealed that all the plant extracts significantly inhibited the mycelial growth of A. alternata. Effect of these five plant extracts varied with the concentrations. Leaf extract of E. globulus at 20% concentration caused highest inhibition of mycelial growth of A. alternata (52.6%) followed by C. procera (50.88%), M. azedarach (48.21%) and D. stramonium (47.42%), whereas the lowest inhibition (37.52) of mycelial growth was recorded at 5% leaf extract concentration in case of A. indica as compared to control. However, seed treatment at 20% concentration of all the tested plant extracts was also found to be effective in eliminating majority of fungi and reducing the relative frequency of seed-borne fungi occurring on the seeds and also results in percent germination increase in both standard blotter and agar plate method over control.

The inhibitory effect of essential oil of flowering buds and potential extracts of Eucalyptus camaldulensis Dehn (leaf, Bark and Flowering Buds) were evaluated on the most aggressive isolate of Bipolaris sorokiniana from wheat crop by agar well diffusion, food poison technique and macro-dilution assay. The mycelial growth was evaluated over four periods (3; 6; 9 and 30 days from incubation) with nine concentrations of essential oils (0.5%; 01%; 2.5%; 05%; 7.5%; 10%; 15%; 50%; 100%) and 3 concentrations (01%; 05% and 10%) of effective extracts. E.oil showed a maximum zone of inhibition of 90 mm diameter and mycelia growth 0.00 ± 0.00 compares to control 40.00 ± 0.00 after 9 days of incubation at 50% and 100% concentration. The extracts of F. buds showed the strongest active values (P<0.05) with a 29.10 ± 0.92 ZOI compared to water extract (19.80 ± 0.33). The ethanol and methanol fruit extracts showed highest minimum inhibitory concentration (08 mg/mL) than water extracts (200 mg/ml) against B. sorokiniana, while minimum fungicidal concentration values for ethanol and methanol fruit extract 40 mg/mL and water extract 300 mg/mL. Extract treated hyphae were collapsed, damaged or thinner when compared with the control. This Study reveals that, F. buds were the potential part of plant. The E.oil and ethanol extract of F. buds were consider most effective that shows considerable potency (up to 97% in-vitro inhibition) than the bark and leaves solvents extracts, while no inhibitory effect was noticed for the aqueous extract of leaves and bark in combating the pathogen.

Faba bean (Vicia fabae L.) is one of the most important pulse crops in Ethiopia and is now cultivated on large areas in many countries. In most growing areas, however, the production of the crop is constrained by several disease infections, including fungal diseases. Black root rot caused by Fusarium solani is the most destructive disease of faba bean. The antagonistic potentials of locally isolated Trichoderma spp. from rhizosphere soils of faba bean plants in the highlands of northeastern Ethiopia were evaluated against F. solani, responsible for black root rot. All isolates of Trichoderma spp. had strong biological control activity against F. solani in vitro as well as in vivo pot experiment. Under dual culture, the percentage of mycelial growth inhibition of F. solani by the Trichoderma ranged from 33.9 to 67.0%. The highest (67.0%) inhibition was obtained from isolate TS036, while the lowest (33.9%) by isolate TS015. Pathogen-inoculated faba bean plants grown in pots that were ...

Antifungal activities of nineteen plant extracts were tested in 2010 with the objectives of screening potential plant extracts against Colletotrichum gloeosporioides under in vitro and anthracnose caused by Colletotrichum gloeosporioides, on papaya (Carica papaya L.) during storage. Ethyl acetate extracts of Lantana camara resulted in the highest inhibition (with inhibition zone of 35.3 mm) and showed strong activity against C. gloeosporioides. Inhibition levels of spore germination that reached 88.7, 85.8, 85.1 and 84.6% were recorded over the control by extracts of Lantana camara, Lantana viburnoides, Echinops sp. and Ruta chalepensis. Four aqueous extracts were evaluated for control of anthracnose under in vivo for 14 days, and Echinops sp. (25%) was found to be most effective in the reduction of disease development and maintaining the overall quality of papaya fruit. Further studies on isolation and characterization of the active (antifungal) compounds are needed.

Juniperus procera is an evergreen dioecious more seldom monoecius tree, which belongs to the family Cupressaceae and the only Juniper species, which is found in the mountains of East Africa and it is an important indigenous forest tree species in Ethiopia. However J. procera is subjected to a serious attack by the slow growing white heart-rot fungus, Pyrofomes demidoffii. Resin has been reported to be active against wood colonizing fungi, however, the role of resin of J. procera in protecting the tree from the attack of P. demidoffii is not known. Therefore this study has initiated to assess the inhibitory effect of resin from J.procera against a white rot fungi P. demidoffii. Resin and basidiocarps of P. demidoffii was collected from infected J. procera trees at Menagesha Suba Forest situated 30 km South West of Addis Ababa, Ethiopia. The antifungal activity of J. procera resin against P. demidoffii was tested using agar dilution assay technique and an impressive result was observed. The MIC value of resin extract was within the range of 5 to 6 mg/100 ml MEAP. Phytochemical screening test for resin extract was done and it revealed the presence of alkaloids, saponins, terpenoids, phenolic compounds, flavenoides and fixed oils and the absence of carbohydrate, glycoside, steroids and fats. The crude extract of J. procera resin was fractionated into six fractions with column chromatography using different organic solvents and all fractions run on Thin Layer Chromatography (TLC) plate using benzene: methanol (18:6) and benzene: ethanol: ammonia (18:2:1). All fractions gave different retention factor (Rf) in each developing solvents.

Tomato cultivation in Nigeria and around the world is seriously threatened by disease infection. Soilless cultivation and gene engineering are modern innovations used worldwide to ensure production of quality disease-free vegetables; yet annual crop loss still persists. In 2011, a commercial vegetable farm in Apẹtẹ, Ibadan, Nigeria was totally ravaged by a fleet of disease infection. 36 infected tomato samples were annihilated from 6 cultivars for laboratory analysis. Crude plant extracts were employed as treatments. The test plants were arranged in 4 × 3 × 2 × 3 × 3 (experimental plots) and 4 × 3 × 3 (control plot) layouts. The tomato plants were basically infected by fungal diseases. The disease symptoms were totally eradicated by the applied botanicals (100% healthy tomato plants). There was an appreciable increase in plant heights of the treated tomato plants (30.9 cm, 30.2 cm, 27.5 cm and 26.5 cm respectively) compared to those in the control plots (24.1 cm, 22.3 cm, 23.3 cm and 18.6 cm, respectively). The results obtained so far showed that plant extracts was an effective alternative for the systemic and hazardous chemicals used in tomato plant disease management.

Poor seedling establishment in rice is one of the problems in Guilan province as the second most important rice-growing locations in Iran. The aim of this study was to evaluate the contamination occurrence of rice seed in five locations of Guilan province to seed-borne fungi and their effects on germination characteristics. Five seed sample of Hashemi variety obtained from leading farmers from each location, and their germination characteristics and the rate of contamination to Fusarium moniliforme, Bipolaris oryzae, Aspergillus niger, A. flavus, Penicillium sp., Alternaria padwickii was evaluated using the PDA and standard blotter methods. The assessment results showed that among the seed-borne fungi, two species A. niger and A. flavus exhibited the highest severity in both methods. Samples from Rasht and Zeybaknar locations showed the most contamination to A. flavus and A. niger. A positive and significant linear relationship was observed between daily precipitation and relative humidity with severity of A. flavus and A. niger fungus. A. niger, A. padwickii, daily precipitation and average minimum temperature had the most influence on germination characteristics. Among the studied factors, A. niger had high negative impact compared to other factors on all rice seed germination characteristics. Among the study locations, quality of seeds in Rostam-Abad in terms of germination percentage, germination rate, germination uniformity and electrical conductivity had the best state. The results of this study showed that the low precipitation and low daily average humidity along with higher number of sunshine hours in the Rostam-Abad caused reduction in activity and abundance of fungi, led to improve the quality of produced seed.

Fungal pathogens namely Alternaria alternata, Botrytis cinerea, Glomerella cingulata, Monilinia fructigena, Penicillium expansum are reported to cause considerable post harvest losses in the state of Himachal Pradesh in India. Bio formulation comprising of six botanicals (seed/leaves) and cow urine were found effective for the management of post-harvest rot in apples. Fruit dip and wrappers impregnated with the bio formulations resulted in 84.7 per cent reduction in the post harvest rot after 75 days of storage at 4°C. Bio formulation treated fruits resulted in better fruit firmness and low TSS (14-16%).

Faba bean (Vicia fabae L.) is one of the most important pulse crops in Ethiopia and is now cultivated on large areas in many countries. In most growing areas, however, the production of the crop is constrained by several disease infections, including fungal diseases. Black root rot caused by Fusarium solani is the most destructive disease of faba bean. The antagonistic potentials of locally isolated Trichoderma spp. from rhizosphere soils of faba bean plants in the highlands of northeastern Ethiopia were evaluated against F. solani, responsible for black root rot. All isolates of Trichoderma spp. had strong biological control activity against F. solani in vitro as well as in vivo pot experiment. Under dual culture, the percentage of mycelial growth inhibition of F. solani by the Trichoderma ranged from 33.9 to 67.0%. The highest (67.0%) inhibition was obtained from isolate TS036, while the lowest (33.9%) by isolate TS015. Pathogen-inoculated faba bean plants grown in pots that were treated with antagonists had taller plant heights and biomass than the Trichoderma untreated control inoculated with F. solani. The Trichoderma isolates significantly reduced black root rot severity on faba bean seedlings with disease reduction ranging from 64.4 to 74.6% over control. Use of Trichoderma species can be a potential source of biological control agents for the management of black root rot in faba beans grown in the region. Hence, the potential Trichoderma isolates under field condition might used as a components in the integrated management of F. solani that caused faba bean black root rot in the highlands of northeastern Ethiopia.

Fire blight (Erwinia amylovora) causes blossom and shoot blight ultimately forming cankers on woody tissues. The magnitude of late season symptom development has not been reported on apple in natural infections. Quantitative and qualitative changes of fire blight symptoms were monitored from July 2007 to April 2008 on cultivars Idared and Golden Delicious in northern Serbia with Idared displaying the highest number of symptoms. In July, shoot blight dominated with 67-88% necrotic shoot tips and completely necrotic shoots. Early blight led to formation of 7-18% cankers of determinate type. Between mid-July and end of September, the number of cankers increased from 65 to 80% on both cultivars. New cankers were of indeterminate type, suitable for pathogen overwintering. Cankers originated from extensive late season pathogen stem invasion from previously diseased shoots. Necrosis size on both cultivars increased significantly between July and September. Increases in canker number and necrosis size indicate a high level of renewed pathogen activity late in the season and its ‘preparation’ for overwintering. Poor winter pruning in one orchard resulted in considerable number of symptom units which constituted potential infection sources. The high magnitude of late season symptom changes, detected under severe natural infections, shows that the pathogen is vigorously active within previously formed symptoms and that pathogenesis continues clandestinely. The results underline the importance of the often neglected part of late season fire blight development for pathogen survival and enforce the requirement for eradication of cankers as primary sources of inoculum for the next season.

Ethiopian barley landraces are recognized as an important genetic resource with which a search for tolerance to biotic stresses is of worth. In present study, 585 barley ( Hordeum vulgare L.) landraces collected from 13 barley producing zones of Ethiopia were evaluated along with 10 improved checks for resistance to BYDV serotype PAV under field conditions at Sinana and Goba during 2018 and 2019 cropping seasons. The trial was laid out in an augmented design consisting of six blocks. Data on disease incidence, severity and some agronomic traits were recorded. The result of analysis showed highly significant variations among landraces for disease incidence, severity and agronomic traits. The BYDV incidence and severity varied from 0.90 to 45.3% and 12.0 to 58.0%, respectively. Similarly, significant variations in terms of regions of origin, altitude classes and kernel row number were observed among landraces. Landraces originated from Arsi, Gojam, Bale and Gonder had significantly lo...

Matsucoccus matsumurae (Kuwana) (Hemiptera: Coccoidea: Matsucoccidae) is an invasive alien species and a destructive pest of two native Chinese pines, Pinus tabulaeformis Carr. and P. massoniana Lamb., throughout the eastern regions of China. The pathogenicity of three entomopathogenic fungi, Lecanicillium lecanii strain V3.4504 and V3.4505, Fusarium incarnatum-equiseti strain HEB01 and Lecanicillium fungicola strain HEB02, against M. matsumurae was tested in four instars, to evaluate their potential as a biological control agent. The results showed that the four strains caused disease and death of the scale insect, among which the L. lecanii strains V3.4504 and V3.4505 displayed stronger virulence than the F. incarnatum-equiseti strains HEB01 and L. fungicola strain HEB02 to M. matsumurae in the 2 nd-instar nymphs and the adult females. Furthermore, L. lecanii V3.4505 was most virulent to M. matsumurae. The adult females and the male 3 rd-instar nymphs of M. matsumurae were susceptible to L. lecanii V3.4505; the adult females were more susceptible at LT 50 = 1.96 than the 3 rd-instar nymphs at LT 50 = 5.67. The body surface structure, cuticle thickness and wax secretions of M. matsumurae impacted the fungal infection. L. lecanii is a promising biocontrol agent, and newly emerged male 3 rd-instar nymphs and adult females are a crucial period of the insect's life cycle for M. matsumurae biocontrol.

Arabica Coffee is an important crop in the national economy of Ethiopia. Coffee berry disease caused by the fungus Colletotrichum kahawae Waller and Bridge is the most devastating threat to Coffea arabica L. production in Africa at high altitude. Hence, this study was carried out for Variation of a representative Colletotrichum isolates of Gurage zone of major coffee producing areas using cultural, morphological and pathological criteria. Out of 33 sample 13 representative C. kahawae isolates from the study area and one Gera isolate were isolated from infected green coffee berry which showed significant variations in their cultural, morphological characteristics and pathogenicity. Mean radial colony growth rate of isolate showed significant variation (p&lt;0.001) with the range of 2.67 to 4.08 mm/24hrs on PDA in EZA and CA1 isolates, respectively. Conidial size also showed significant difference (p&lt;0.001) in the range of 5 to 6.04 and 9.24 to 10.0 µm in width and length, respecti...

The study was conducted to assess the influence of different agro-ecological zones and cropping seasons on the incidence and severity of maize streak disease (MSD) in Ghana. Field surveys were conducted in two districts each of the coastal savannah, forest, and transitional agro-ecological zones of the Volta region to assess the incidence and severity of MSD in farmers' fields, during the 2014 minor and 2015 major cropping seasons. The disease assessment was carried out in 12 fields from each district, and for each field on both maize plants growing under tree shade and in open parts of the field. The plants were scored for disease severity based on a 1-5 visual scale (1=no infection and 5=very severe infection). Percentage total N, available P, exchangeable K, organic matter levels and pH were determined from soil samples collected from each of the fields surveyed. Incidence and severity of MSD on maize plants growing under tree shade and in open parts of the fields were significantly higher (P<0.05) in the transition zone than in the forest and coastal savannah eco-zones during the 2014 and 2015 cropping seasons. Mean incidence and severity of MSD on maize plants growing under tree shade were significantly higher than those in the open part of the fields in both cropping seasons. The levels of MSD incidence and severity recorded in 2014 were significantly higher (P<0.05) than 2015. Low levels of soil total N, available P, exchangeable K and organic carbon were detected across the three agro-ecological zones. Incidence and severity scores of MSD were significantly and negatively correlated with soil total N, available P, exchangeable K and organic matter (P<0.01). In conclusion, MSD incidence and severity vary with the cropping seasons and agro-ecological zones and are partly affected by low soil fertility levels and tree shades.

Garlic is one of the most important crops widely cultivated throughout the world including Ethiopia. It is the second most widely cultivated Allium species next to onion. The production of the crop is majorly threatened by fungal diseases. White rot of garlic caused by Sclerotium cepivorum, is the most devastating constraint in Ethiopia. A field experiment was conducted to evaluate the effect of fungicide types on incidence and severity of garlic white rot, yield and yield components of garlic and to identify the effective method of fungicides application under rain fed supplemented with irrigation at Debre Berhan University Research site in 2017/18 .The experiment was consisted of three types of fungicides (Apron star, MORE 720 WP and Mancozeb) with three methods of application (clove, clove plus foliar and foliar). The experiment was laid out as RCBD in a factorial arrangement with three replications. Fungicide types and methods of application significantly affected disease incide...

In the present study, cell-free cultures of four isolates of Rhizobium leguminosarum, an isolate of Azotobacter chroococcum and compost tea were investigated for their biocontrol potential against the root parasitic weed Orobanche crenata. Individual cell-free cultures of Azotobacter chroococcum or Rhizobium sp., dual and mixture of cell-free cultures of Rhizobium spp. or compost tea were applied to infested pots in greenhouse conditions. The treatments showed variable effects on many developmental parameters of both faba bean and broomrape. Significant decrease in the number of broomrape attachments, dry weight of the attached tubercles on faba bean roots and the reduction in percentage of broomrape seed germination were recorded. Compost tea, individual and mixture of R. leguminosarum isolates were more reducing on broomrape germination and growth than A. chroococcum alone did; being the former treatment is the best. The reduction in broomrape incidence by compost tea was due to certain phenotypic mechanisms, which acted alone or in combination. These mechanisms included negative effect of natural stimulant broomrape on seed germination, prevention of radical penetration inside the host roots, parasite yield reduction, and thus increasing the growth and vitality of faba bean. In vitro experiment indicated that seed germination percentage of broomrape was also negatively affected by the combination of root-exudates and compost tea. Radical apexes of the germinated seeds were distorted. These distortions may prevent the radicals to follow up the infestation. In conclusion, the study presents the potential of R. leguminosarum isolates and compost tea in biocontrol of broomrape. More investigations should be carried out with viable bacterial cells on the parasite plant before use in sustainable agricultural systems.

Chickpea (Cicer arietinum L) is one of the important grain legume crops in Africa particularly in Ethiopia which widely grown in marginal soils and usually as rotational crops in highland and semi-highland regions of the country and also as a source of cash to the farmers and foreign currency in Ethiopia. However, its production is totally affected by many pest and diseases. Among biotic stresses, wilt or root rot diseases are considered as the major problems in chickpea production. Therefore, the present study was conducted to determine the assessment of chickpea wilts disease intensity, in West Shewa, Ethiopia. Field survey was carried out in purposively selected Kebeles of Ambo and Dendi districts of West Shewa, Ethiopia. The results of the study revealed that, among 70 chickpea fields surveyed in both districts, the overall mean prevalence and incidence of the disease were 92.9%, and 35.09%, respectively. The higher prevalence and incidence of the disease was recorded in Ambo di...