Tomato Bacterial Disease Research Articles

Enhancing host-pathogen phenotyping dynamics: early detection of tomato bacterial diseases using hyperspectral point measurement and predictive modeling.

Early diagnosis of plant diseases is needed to promote sustainable plant protection strategies. Applied predictive modeling over hyperspectral spectroscopy (HS) data can be an effective, fast, cost-effective approach for improving plant disease diagnosis. This study aimed to investigate the potential of HS point-of-measurement (POM) data for in-situ, non-destructive diagnosis of tomato bacterial speck caused by Pseudomonas syringae pv. tomato (Pst), and bacterial spot, caused by Xanthomonas euvesicatoria (Xeu), on leaves (cv. cherry). Bacterial artificial infection was performed on tomato plants at the same phenological stage. A sensing system composed by a hyperspectral spectrometer, a transmission optical fiber bundle with a slitted probe and a white light source were used for spectral data acquisition, allowing the assessment of 3478 spectral points. An applied predictive classification model was developed, consisting of a normalizing pre-processing strategy allied with a Linear Discriminant Analysis (LDA) for reducing data dimensionality and a supervised machine learning algorithm (Support Vector Machine - SVM) for the classification task. The predicted model achieved classification accuracies of 100% and 74% for Pst and Xeu test set assessments, respectively, before symptom appearance. Model predictions were coherent with host-pathogen interactions mentioned in the literature (e.g., changes in photosynthetic pigment levels, production of bacterial-specific molecules, and activation of plants' defense mechanisms). Furthermore, these results were coherent with visual phenotyping inspection and PCR results. The reported outcomes support the application of spectral point measurements acquired in-vivo for plant disease diagnosis, aiming for more precise and eco-friendly phytosanitary approaches.

Determination of the efficacies of different phosphites in the management of tomato bacterial speck disease caused by Pseudomonas syringae pv. tomato

This study tested the efficacy of five different phosphites (calcium, copper, magnesium, potassium and zinc/manganese phosphites) and a fungicide Fosetyl-Aluminum to inhibit bacterial speck disease severity caused by Pseudomonas syringae pv. tomato (Pst) on tomato leaves. The phosphites were applied at the recommended doses to the Pst inoculated plants in pots by foliar spraying at one-week intervals for a total of 4 weeks. The plants were kept in a controlled greenhouse under relative humidity (%75-90) and temperature (22-24 °C) until disease symptoms appeared in the control plants. Phosphites and Fosetyl-Aluminum inhibited the Pst symptoms on tomato leaves by 42.1-75.0% in the first and 22.8-90.3% in the second experiments. This study demonstrated the direct influence of phosphites on tomato bacterial speck. The study suggested that phosphites can be an effective alternative for the chemical control of tomato bacterial disease. The bacterial agent, Pst, causes bacterial speck disease in tomatoes. The initial symptoms of the disease are water-soaked, small dark brown spots surrounded by a yellow halo on tomato leaves. Since the pathogen is seed-borne, control of the disease is difficult.

BACTERIAL AND FUNGAL PATHOLOGIES OF TOMATO (SOLANUM LYCOPERSICUM L.): STATUS OF THE DISEASES AND CONTROL PRACTICES OF FARMERS IN TOGO

Tomato (Solanum lycopersicum L.) is of great socio-economic Tomato (Solanum lycopersicum L.) is of great socio-economic importance. Unfortunately, its production is limited in Togo by fungal diseases and bacterial wilt caused by Ralstonia solanacearum (Rs). The objectives of the study are to establish the status of major tomato diseases in Togo and control approaches used by the producers. The methodology led to a field survey allowing the evaluation of the incidence of fungal and bacterial diseases of tomato and the identification of their endogenous control methods. In the laboratory, the isolation and identification of the pathogens responsible for these diseases were carried out. The results show that the major diseases of tomato in Togo were, spots, organ decay and wilting plants. The incidence rate of fungal diseases ranges from 18.8% to 75% (fields) and from 0% to 15% (plants). The pathogens responsible are Sclerotium rolfsii (7.5%) Sclerotinia sclerotiorum (1.5%), Alternaria solani (2.5%) and Fusarium oxysporum (4.38%). The incidence rate of Rs wilt is 100% (field) and ranges from 10% to 43.33% (plant). The PCR test revealed that the bacterium responsible for tomato wilt in Togo is Rs belonging to phylotype I, Sequevar 17. Synthetic chemical pesticides are used to control these pathologies, which is a problem for human and animal health and environmental protection. Chemical pesticides have been identified, 60% of which are insecticides and 30% fungicides. The study revealed unproper practices in the management of pesticides in region covered by the research, leading to sanitary risks for farmers.

Wirkung von Silberoxid-Nanopartikeln auf das Wachstum, die Aktivitäten von Abwehrenzymen und pilzliche und bakterielle Erkrankungen von Tomaten

Wirkung von Silberoxid-Nanopartikeln auf das Wachstum, die Aktivitäten von Abwehrenzymen und pilzliche und bakterielle Erkrankungen von Tomaten

Endophytic bacteria from Euphorbia antiquorum L. protect Solanum lycopersicum L. against bacterial wilt caused by Ralstonia solanacearum

BackgroundBacterial wilt caused by Ralstonia solanacearum (syn. Pseudomonas solanacearum) is the most devastating bacterial disease of tomato (Solanum lycopersicum L.) occurring in tropical zones with consequential substantial yield losses in production fields. Currently, microbial technology in cropping systems has directed investigations toward biological control agents (BCAs), emphasizing the use of plant endophytes, including bacteria. The present work aimed to evaluate the potential of endophytic bacteria from Euphorbia antiquorum L. to suppress bacterial wilt incited by R. solanacearum in plants.ResultsOf the 10 endophytic species screened in vitro for their antagonistic activity, 6 exhibited promising potency with minimum inhibitory concentration (MIC) values ranging from 62.50 to 7.81 µg/ml. These species also produced cell wall-degrading enzymes (amylase, protease and cellulase), ammonia, siderophores, indole acetic acid and salicylic acid. The 3 most potent species (B. amyloliquefaciens CBa_RA37, B. velezensis CBv_BE1 and B. amyloliquefaciens CBa_BFL2) enhanced the germination of tomato seeds and protected young tomato plantlets from the devastating effects caused by R. solanacearum infection.ConclusionsThis investigation demonstrated that these endophytic bacteria from E. antiquorum L. endowed with the ability to improve the growth and protection of tomato plants could be further developed as potential biopesticides to help mitigating the effect of bacterial wilt in tomato farms. Further investigation will set the baseline for formulation and evaluation of their efficacy in the open field.

Biological control of Streptomyces sp. UT4A49 to suppress tomato bacterial wilt disease and its metabolite profiling

ObjectivesEvaluation of Streptomyces isolated from Udhagamandalam, The Nilgiris, Tamilnadu, India for the biocontrol potential against the phytopathogen Ralstonia solanacearum and its metabolite profiling. MethodsStreptomyces strains were screened for plant growth promotion and antagonistic activity against R. solanacearum in in-vitro. The metabolite profiling of strain UT4A49 was studied through gas chromatography coupled with mass spectroscopy (GC–MS) analysis. Further, the identified lead compound 2,4-Di-tert-butylphenol (2,4-DTBP) was analyzed for its mechanism of action through in-silico docking study. The bioorganic fertilizer (BOF) amended potential Streptomyces strain UT4A49 was studied for biocontrol activity against R. solanacearum on tomato seedlings through pot culture experiments. ResultsThe Streptomyces strain UT4A49 showed the promising production of indole acetic acid (IAA) (76.0 ± 2.0 µg/ml), siderophore, ammonia, amylase, protease, cellulase as well as it solubilized the phosphate in-vitro. The strain UT4A49 showed strong in vitro antagonistic activity against R. solanacearum with the inhibition zone of 19.83 ± 0.44 mm in diameter. The isolated major compound, 2,4-Di-tert-butylphenol was showed strong inhibition against R. solanacearum. In silico docking study revealed that the 2,4-DTBP showed lower binding energy score with all targeted proteins which found better protein–ligand binding stability. In the pot experiment, biocontrol activity of BOF amended Streptomyces strain UT4A49 showed significant biocontrol efficacy was 78.5% against R. solanacearum in tomato seedlings. The strain UT4A49 was identified as Streptomyces sp. based on its morphological and molecular properties. ConclusionsThe detailed literature survey revealed that this is the first report on strong bioactive properties of 2,4-DTBP against R. solanacearum. This present study proved that bioorganic fertilizer amended with Streptomyces sp. UT4A49 is a promising biocontrol agent for tomato bacterial disease control.

Tomato bacterial diseases in West Azerbaijan province of Iran

Tomato bacterial diseases in West Azerbaijan province of Iran

Identification and application of Streptomyces microflavus G33 in compost to suppress tomato bacterial wilt disease

Tomato bacterial wilt caused by Ralstonia solanacearum is the most destructive disease impacting production. Application of bioorganic fertilizer (BOF) containing antagonistic microorganism to suppress tomato bacterial wilt disease may be a promising disease control strategy. Here, we used organic waste materials, specifically biogas residues, cattle manure and rice straw, in composting with antagonistic strain G33 isolated from the rhizosphere soil of a healthy tomato plant to produce BOF. Strain G33 was identified as Streptomyces microflavus by morphological and culturing traits and by 16S rRNA gene sequence analysis. We conducted a field experiment with control treatment, organic fertilizer and BOF-G33 to characterize suppression of tomato bacterial wilt disease. Our results indicate that the optimal combination containing (w/w) 40% biogas residues, 40% cattle manure and 20% rice straw can increase the nutrient contents of the compost product, prolong the thermophilic period and increase the decomposition rate of organic matter and the humification degree. A combination of strain G33 and mature compost produced under optimal conditions resulted in the spore number of 5.75 × 109 CFU/g on the sixth day of fermentation. Field experiments showed that BOF-G33 significantly decreased the incidence of tomato wilt; the disease biocontrol efficiency was 64.4%. In addition, application of the BOF-G33 significantly reduced the pathogenic R. solanacearum populations and increased the abundance of beneficial indigenous flora in the rhizosphere soil, which might have been the key factors in constraining the disease. In conclusion, this study showed that bioorganic fertilizer with Streptomyces microflavus G33 is a potential biocontrol agent for controlling tomato bacterial disease.

Chemical characterization and in vitro antimicrobial activity of honeybee propolis and Scaptotrigona jujuyensis geopropolis against tomato pathogenic bacteria

The antimicrobial activity of four concentrations of hydroalcoholic extracts from honeybee propolis and Scaptotrigona jujuyensis geopropolis was screened in vitro against five tomato pathogenic bacteria. The agar-well diffusion method was used and the tested bacteria were Clavibacter michiganensis subsp. michiganensis, Xanthomonas gardneri, Xanthomonas vesicatoria, Pseudomonas corrugata, and Pseudomonas mediterranea. The main chemical characteristics of propolis and geopropolis, including the polyphenol profile through HPLC-DAD, were also determined. Geopropolis raw sample presented higher values of moisture (7.78%), waxes (50.79%) and ashes (3.69%) than propolis (4.59%, 31.16% and 2.42% respectively). The total polyphenol content and the dry extract were higher in propolis hydroalcoholic extract (3.83 mg eq galic acid mL-1 and 7.87%, respectively) than in the extract of geopropolis (0.16 mg eq galic acid mL-1 and 0.15%, respectively). Chromatographic analysis confirmed the presence of caffeic acid, quercetin, 1,5,7-trihydroxy-flavanone, apigenin, pinobanksin, chrysin, pinocembrin, and galangin in both extracts. The antimicrobial assay showed significant differences between the hydroalcoholic extract activities, as well as between the sensitivity of the tested bacteria. Propolis hydroalcoholic extract dilutions had an inhibitory effect over four of the five tested bacteria, while geopropolis hydroalcoholic extract dilutions were only effective against C. michiganensis subsp. michiganensis, and to a lesser extent. The sequence of bacteria sensitivity to propolis treatments was: C. michiganensis subsp. michiganensis > X. gardneri > X. vesicatoria > P. corrugata. Pseudomonas mediterranea was not sensitive to any of the hydroalcoholic extracts. The antimicrobial activity of both extracts was dose-dependent where the most concentrated treatments were the most effective (15.0 mg mL?1 of geopropolis and 78.7 mg mL?1 of propolis dry extract, respectively). The polyphenol content and the HPLC-DAD profile of the hydroalcoholic extracts disclosed differences in chemical composition that helped to explain the outcomes of the in vitro assay. These results are a contribution to the characterization of bee bioactive products, specifically to propolis and geopropolis. This study indicates the likelihood of using propolis as a non-conventional strategy to control tomato bacterial diseases.

Tomato bacterial diseases in plastic greenhouses and fields in Mersin, Turkey

Tomato bacterial diseases in plastic greenhouses and fields in Mersin, Turkey

Soil solarization as a sustainable solution to control tomato Pseudomonads infections in greenhouses

The reduction or phase-out of soil fumigants according to European directives has led to a re-evaluation of sustainable heat-based techniques and exploiting solar energy, e.g., solarization that was used successfully for the eradication of fungi, weeds, and nematodes. Since the beginning of the current century, bacterial infections caused by phytopathogenic Pseudomonads have been increasingly reported as threat for many horticultural crops worldwide. Nowadays, this disease represents a limiting factor for the tomato production in the Mediterranean basin under greenhouse conditions. Therefore, we tested the effects of soil solarization in controlling natural infections caused by Pseudomonas fluorescens on tomato cultivations in Sicily (south Italy) from 2010 to 2013 under different greenhouse conditions, i.e., with lateral openings uncovered or kept closed. Four experiments were performed under both wooden-concrete and steel-made greenhouses to compare the performances of innovative and traditional films alone or combined with other control measures (only in partially opened greenhouses) against tomato bacterial infections. All solarization treatments were effective in controlling phytopathogenic pseudomonads except for one carried out in a multi-span steel greenhouse with the side openings kept raised. Tested greenhouse covering and mulching films increased soil temperature up to 9.6 °C at 15 cm and 7.7 °C at 30 cm, respectively, if compared to bare plots. Moreover, solarization treatments proved effective in controlling bacterial infections (up to about 90% reduction of disease amount) and in increasing yield up to 45% relative to the bare plots. Among tested films, EVA showed the best performances both in reducing bacterial infections and increasing tomato yield, innovative polyamide VIF and smoky gray were very promising films while green coextruded could be considered a very attractive film since it can be left on after solarization process as mulch for tomato transplanting. This study shows for the first time the feasibility and sustainability of soil solarization performed with innovative materials in managing tomato bacterial diseases in greenhouse.

Bacterial diseases of tomato plants in terms of open and covered growing of Ukraine

Abstract It was established that the main causes of mass diseases of tomato in covered ground in Ukraine are agents of bacterial black spotting, bacterial speck and in open ground are agent of bacterial cancer of tomato plants. Typical symptoms of diseases are wilting and die-off of young plants, blackening of fiber vascular bundles, black spotting of leaves and fruits, and fruit stem rot. It was studied morphological and cultural, as well as physiological and biochemical properties of the selected strains of the agents of tomato bacterial diseases. We recommended biological preparations Phytocide and Phytohelp based on the bacteria Bacillus subtilis , to restrict the development of the agents of bacterial black spotting Xanthomonas vesicatoria and bacterial cancer Clavibacter michiganensis subsp. michiganensis .

Investigation of the influence of salicylic acid on the causes of bacterial diagnostics of tomatoes

The aim of this work was to investigate the ability of the SA to inhibit the growth of strains of Xanthomonas vesicatoria, Pseudomonas syringae pv. tomato and Clavibacter michiganensis subsp. michiganensis in nutrient media and suppress the development of bacterial black spot, bacterial spotting and bacterial cancer in tomato plants in terms of artificial infection.Methods. Virulence of strains of X. vesicatoria, P. syringae pv. tomato and C. michiganensis subsp. michiganensis in laboratory environment was determined by artificial infection of stalks and leaves of tomato plants by injection. Accounting of strains aggression was carried out using the 10-point scale. SA on bacteria was studied by perforation method.Result. The author has established antibacterial effect of salicylic acid on the pathogens of tomato bacterial cancer, black bacterial spot and bacterial spotting in the medium, and its potential possibilities of disease inhibition in terms of artificial inoculation. It is established an authoritative increase in areas of stunted growth of pathogen strains with salicylic acid in proportion with the increase of its concentration. SA application has reduced the degree of development of tomato bacterial diseases by 8–65 % in terms of the artificial inoculation. Spraying tomato plants with SA solution was more effective than root soaking.Conclusions. SA solutions showed high antibacterial activity against pathogens of bacterial cancer C. michiganensis subsp. michiganensis and bacterial black spot X. vesicatoria with no growth zone of 70–80 mm. Increased SA concentrations caused the increased effectiveness of inhibition of tomato plants bacterial diseases

Protective effect of three brown seaweed extracts against fungal and bacterial diseases of tomato

The effect of extracts of the brown algae Cystoseira myriophylloides, Laminaria digitata, and Fucus spiralis against the tomato pathogens Verticillium dahliae and Agrobacterium tumefaciens was evaluated in vitro and in the greenhouse. A significant inhibition of growth was observed only with methanolic seaweed extracts (MSE). Disease resistance was assessed in the greenhouse against Verticillium wilt using spray application of aqueous seaweed extracts (ASE) on the whole plant or using seed imbibition. Both methods significantly reduced disease severity whatever the algal species, though protection observed after seed treatments was higher than that observed after spray treatment. Spray application of ASE from C. myriophylloides and F. spiralis also resulted in significant reduction of Crown gall disease caused by the bacterial pathogen A. tumefaciens. ASE-treated plants had significantly higher levels of activity of defense enzymes polyphenol oxidase and peroxidase compared to the control. ASE did not inhibit mycelium growth of V. dahliae or development of A. tumefaciens in vitro; it is therefore suggested that induced resistance is probably the main mechanism of protection afforded by ASE.

Effect of Pyraclostrobin Application on Viral and Bacterial Diseases of Tomato.

Quinone outside inhibitors (QoI) are powerful fungicides, which have been reported, additionally to their fungicide activity, to increase plant capacity to activate cellular defense responses and to promote plant growth. In this work, the effect of the QoI class fungicide pyraclostrobin was examined against Cucumber mosaic virus (CMV), Potato virus Y (PVY) and Pseudomonas syringae pv. tomato in tomato plants following artificial inoculation of the plants with the pathogens. Under controlled environmental conditions, pyraclostrobin delayed viral and bacterial disease development, even if P. syringae pv. tomato internal population levels were not affected significantly. In contrast, under field conditions in commercial greenhouses, a reduced CMV disease incidence throughout the tomato cultivation period was recorded. Gene expression analysis indicated an effect of pyraclostrobin application on tomato MAPKs transcript levels and a possible interference with plant stress responses.

DEVELOPMENT OF INNOVATIVE MULTI-LEVEL KNOWLEDGE BASED TOMATO DISEASE FACTSHEETS

Tomato bacterial diseases cause significant losses annually to fresh market, processing and greenhouse producers worldwide. As researchers continue to better understand the biology of bacterial pathogens and develop effective management strategies to reduce disease incidence and severity, improved methods are needed to translate and exchange this new knowledge to a diverse and dynamic group of tomato stakeholders. However, identifying tools or methods that present knowledge in a way that will facilitate uptake and application of the knowledge can be challenging. In addition, very little science-based information is available on the best way to deliver plant disease management strategies to vegetable producers. Based on surveys conducted to identify midwestern vegetable producers’ preferences for receiving information regarding food safety hazards and the fact that the need for communication in society is heterogeneous and requires differentiation according to target groups, innovative factsheets for bacterial leaf spot (BLS), bacterial speck, bacterial canker, and pith necrosis were developed. Each factsheet contains science-based information that incorporates recent changes in the taxonomic classification, epidemiology, management and identification of the pathogens that cause these diseases. The information provided is relevant to new producers or home gardeners (beginners), experienced producers (advanced) and plant disease diagnosticians. Information from all three levels of knowledge is summarized into one downloadable factsheet that is available in English and Spanish. Additionally, uncommon terminology is defined in English and Spanish, images of diseases with similar and potentially confusing symptoms are provided and resources for diagnosing each disease are included. The factsheets were published on January 23, 2013 at www.vegetablediseasefacts.com. Over a 2-month period the factsheets had 93 new visitors and 112 returning visitors. The bounce rate for new and returning visitors was 8.6 and 52.7%, respectively. While the majority of visitors (94.7%) were from Ohio, visitors were also from Florida, Illinois, Louisiana, North Carolina, New York, Pennsylvania, Virginia, and Wisconsin. International visitors were from Guatemala, India, China, Colombia, Egypt, Iran, Italy, Mexico and Senegal. Bacterial leaf spot was the most frequently visited and downloaded disease factsheet; followed by bacterial canker, pith necrosis and bacterial speck. User engagement of each factsheet continues to be monitored and additional factsheets targeting high tunnel and organic tomato producers are currently being developed.

Reação em campo à murcha bacteriana de cultivares de tomate em Roraima

A murcha bacteriana causada por Ralstonia solanacearum (Smith) é a doença bacteriana mais importante do tomateiro na Região Norte do Brasil. Os objetivos deste trabalho foram avaliar o nível de resistência de cultivares de tomate, avaliar o progresso da murcha bacteriana nesses genótipos a fim de conhecer o comportamento da doença nos diferentes estádios de desenvolvimento da cultura, para auxiliar no manejo da epidemia, e determinar a época crítica para o desenvolvimento da doença nessas cultivares nas condições de Roraima. Os experimentos foram conduzidos em um campo naturalmente infestado com a biovar 1 de Rasltonia solanacearum, por dois anos. A área tinha um histórico de quatro anos de plantios sucessivos com plantas de tomate suscetíveis à murcha bacteriana, e as perdas alcançando até 100%. Para condução do experimento foram utilizadas mudas das cultivares Majestade, Nemonetta, Carmen, Liliane, Santa Clara, Sensação, San Vito, Gaúcho Melhorado, Hector e Laura. Foram feitas seis avaliações do número de tomateiros que apresentavam murcha irreversível e/ou morte durante o ciclo da cultura. Foram determinadas as variáveis área abaixo da curva de progresso da doença (AACPD) e a taxa de progresso da doença (r), incidência média (Y50), incidência máxima (Ymáx) e a incidência final da doença. Os valores de AACPD e da variável r para a cultivar Majestade foram menores que para as demais, demonstrando que houve menor incidência de plantas doentes nesta cultivar, indicando resistência. Embora o nível de resistência apresentado por esta cultivar não seja muito elevado, o cultivo da mesma é recomendável e viável para o plantio no Estado de Roraima, especialmente considerando-se os altos preços do tomate, que são adquiridos de outras regiões produtoras no país, embora somente esta resistência não garanta, sozinha, o controle adequado da doença, sendo necessárias outras medidas de controle associadas.

Bacterial diseases of tomato in southern Spain: application of a detached tissue assay to evaluate bacterial pathogenicity

Tomatoes are one of the most important crops in southern Spain, especially during the cold season. As a preliminary step in the design of an integrated disease management programme for tomato, a study on the occurrence of bacterial diseases in tomato houses of Almeria (ES) was carried out during the 1993/1997 growing seasons. Sixty-four bacterial strains were isolated from tomato plants showing symptoms of bacterial diseases and 41 of them (64%) were characterized as pathogenic. The bacterial tomato pathogens most frequently isolated were Erwinia carotovora subsp. carotovora, Pseudomonas corrugata, Pseudomonas syringae pv. tomato and Xanthomonas vesicatoria. The pathogenicity of the bacterial isolates on tomato was tested by the conventional seedling assay and by an in vitro assay using detached tissues developed in our laboratory. Close correspondence between the two assays was observed. An in vitro detached tissue assay is proposed for determining the pathogenicity of bacterial isolates on tomato.

The most important bacterial diseases of glasshouse tomato in Russia

Studies of glasshouse tomato bacterial diseases agents complex have been conducted in some regions of Russia in 1987–1996. Microbiological analysis of seeds and plants of local and foreign selection made it possible to assess quality of the seed material and phytosanitary condition of tomato plants. It's very important to obtain and to cultivate healthy seed material of high quality. This is one of the main conditions of preventing epiphytoty and obtaining ecologically pure agricultiral products.

Towards the biological control of fungal and bacterial diseases of tomato using antagonistic Streptomyces spp.

This investigation was designed to explore the potential of microbial antagonism in the control of some tomato diseases including bacterial, Fusarium and Verticillium wilts; early blight; bacterial canker. Three Streptomyces spp. were used: S. pulcher, S. canescens and S. citreofluorescens. The in vitro studies showed that an 80% concentration of the culture filtrate of either S. pulcher or S. canescens significantly inhibited spore germination, mycelial growth and spotulation of Fusarium oxysporum f.sp. lycopersici, Verticillium albo-atrum and Alternaria solani. The same concentration of filtrate of either S. pulcher or S. citreofluorescens was detrimental to the bacterial populations of Clavibacter michiganensis subsp. michiganensis and Pseudomonas solanacearum. The in vivo studies involved different treatments: soaking tomato seeds in filtrate of the antagonist prior to sowing, inoculation of the soil with the antagonist 7 days before sowing, and coating of tomato seeds with spores of the antagonist before sowing. The seed-coating treatment was the most effective in controlling all the pathogens at 42 and 63 days after sowing. Soil inoculation with the antagonist 7 days prior to sowing was less effective in controlling the tomato pathogens as compared to seed-coating. The seed-soaking treatment was the least effective in controlling the diseases concerned. The results also revealed that seed-coating with antagonistic Streptomyces spp. significantly improved tomato growth.