Early Blight Disease Of Tomato Research Articles

Biocontrol effect and mechanism of Bacillus laterosporus Bl13 against early blight disease of tomato

Bacillus laterosporus Bl13 has good antagonistic effect on the pathogen of tomato early blight (TEB) disease. A pot experiment was conducted to investigate the effect and mechanism of B. laterosporus Bl13 against TEB disease by measuring biological traits such as plant height, stem diameter, disease index of TEB, activity of plant defense enzyme in leaves, and microbial diversity and community composition in root area. The results showed that B. laterosporus Bl13 could significantly reduce the disease index of TEB disease incidence, increase the activity of defensive enzymes including polyphenol oxidase (PPO) and peroxidase (POD) in leaves, and reduce the effects of the disease on the aboveground and root growth of tomato. Meanwhile, B. laterosporus Bl13 improved soil microbial community structure in the root zone, by significantly increasing the relative abundance of plant growth-promoting bacteria (Bacillus and Pseudomonas) and decreasing that of Olpidium and Haematonectria. The results showed that B. laterosporus Bl13 could enhance plant resistance against TEB disease through improving the activity of defensive enzymes in tomato leaves and increasing the number of beneficial microbes in the root zone.

Efficacy of botanical extracts against early blight disease of tomato incited by Alternaria solani

Early blight is one of the most common and destructive diseases in tomatoes caused by the fungus Alternaria solani. Antifungal activity of six botanical extracts, namely (Datura stramonium) Datura, (Polyalthia longifolia) Ashoka, (Clerodendrum viscosum) wild jasmine, (Eucalyptus globulus) eucalyptus, (Chromolaena odorata), Siam weed extract, (Lantana camera) wild sage extract was antifungal. Each plant extract tested against Alternaria solani, with two concentrations, 5% and 10%, under in vitro and in vivo. The maximum decrease in the growth of mycelium of Alternaria solani with Eucalyptus globulus and Lantana camara (67.68% and 36.72%, respectively) and the minimum disease intensity under in vivo were recorded with Eucalyptus globulus (27.42%).

Isolation, pathogenicity and suitability of different culture media on growth and sporulation of Alternaria solani (ELL. & MART.) Inciting early blight disease of tomato

Early blight is the most common and destructive disease of tomato plants caused by the fungus Alternaria solani. Six culture media were used in this study, namely PDA, Glucose Peptone Yeast Agar, Malt Extract Agar, Tomato Leaf Extract, Oatmeal Agar and Dox Czapek agar extract and evaluated the suitability of the culture medium for fungal growth. It has been noted that PDA and Tomato Leaf Extract Agar promotes pathogen development through the formation of radial growth of 9.0 cm and mainly 8.5 cm within 10 DAI. Oatmeal agar also appeared to be the best medium after PDA and Tomato Leaf Extract Agar followed by Czapek's Dox Agar. The least supported medium was glucose peptone agar with radial growth of fungi of only 4.00 cm. The colony ranged in color from white, cream and olive green to black. When sporulated, oat agar and potato dextrose agar showed excellent sporulation. While on Tomato Leaf Extract Agar and Czapek Dox Agar it was bad.

Antifungal potential evaluation and alleviation of salt stress in tomato seedlings by a halotolerant plant growth-promoting actinomycete Streptomyces sp. KLBMP5084

Salt stress affects plant growth and crop yield reduction, thus how to improve the salt tolerance of plants is full of challenges. Plant growth-promoting rhizobacteria (PGPR), as an environment-friendly treatment to improve salt stress tolerance of plants is widely accepted and has big potential in field application. In this study, a halotolerant actinomycete Streptomyces sp. KLBMP5084 obtained from the root of halophyte Limonium sinense was evaluated for antifungal activity in vitro and applied for the growth promoting of tomato seedlings under salt stress. Results demonstrated that the fermentation broth and the volatile organic compounds (VOCs) of strain KLBMP5084 could inhibit a variety of plant pathogenic fungi, including tomato early blight disease pathogenic fungi Alternaria solani. In particular, the KLBMP5084 inoculation significantly enhance the growth of tomato seedlings compared with the control after irrigating with 200 mM NaCl, with increased fresh weight, shoot length, and the number of fibrous roots. Further, the antioxidant enzymes activity, soluble sugar and proline contents in leaf and stem were also effectively increased, and malondialdehyde (MDA) was decreased. KLBMP5084 inoculation also increased the contents of K+ and Ca2+, reduced the Na+ accumulation in leaf. A total of 191 genes were also observed differentially expressed after KLBMP5084 treatment under salt stress in leaves by transcriptome analysis. Genes involved in the photosynthesis-antenna proteins pathway, isoquinoline alkaloid biosynthesis, zeatin biosynthesis and protein processing of endoplasmic reticulum pathway were enriched to the highest degree, indicating their significance and effects in response to salt stress in tomato seedlings. Collectively, these findings indicate that strain Streptomyces sp. KLBMP5084 has the potential as the biological fertilizer for promoting the tomato seedlings growth under salinity stress.

Bio-Efficacy of 'SUDOTM' (Pseudomonas fluorescens) as a Bio-Control Agent against Early Blight (Alternaria solani) Disease of Tomato

Tomato (Lycopersicon esculentum Mill) is the most popular vegetable crop grown in India as well as in the world which is attacked by several diseases. Among the various diseases, early blight caused by Alternaria solani has become the constraint resulting in huge yield losses. Continuous usage of chemical methods leads to environment, soil and water pollution. However, biological control of diseases is long lasting, inexpensive, eco-friendly and harmless to target organisms. A field bio-efficacy study was conducted for evacuation of SUDO (Pseudomonas fluorescens) for control of tomato early blight disease. The results compiled suggest that the two sprays with 'SUDO' @ 2.0 ml/L followed or preceded by chemical fungicides was found effective in the management of early blight disease of tomato. Minimum PDI of 9.88 was recorded in T-1 treatment (chemical), followed by combination of treatments of chemicals + SUDO with 11.88 to 28.34 PDI which are significantly lower than control treatment (42.40 PDI). Even SUDO @ 2.0 ml/L alone recorded significantly more plant height (17.42%), and fruit yield (58.10%) with reducing early blight disease by 33.16% over control treatment. Similarly spraying of SUDO did not show any phyto-toxic effect on tomato plants.

The Efficacy Test of Nano Chitosan and Phylex in Resistance Early Blight Disease in Tomato Caused by Alternaria Solani Fungus

The Efficacy Test of Nano Chitosan and Phylex in Resistance Early Blight Disease in Tomato Caused by Alternaria Solani Fungus

Deep learning based assessment of disease severity for early blight in tomato crop

Assessment of disease severity is one of the major challenges which helps in the prediction of yield quantitatively and to decide the control factors that improve the yield of any crop. Hence a perfect system is essential to measure the severity level of the disease in order to improve its productivity. An intelligent state of the art technique i.e., deep learning plays an inevitable role in most of the real-time applications including smart farming. Tomato crops are frequently affected by a dangerous fungal disease i.e., early blight, resulting in 100% production loss to farmers. In this work, an identification of early blight disease in tomato leaves is performed by a recently invented paper microscope named Foldscope. Further, a deep Residual Network101 (ResNet101) of Convolutional Neural Network (CNN) architecture is used to measure the severity level of early blight disease in tomato leaves. The dataset in the model is trained by using an open database i.e., PlantVillage dataset for mild, moderate, and severely diseased leaves along with healthy tomato leaves. The results of ResNet101 architecture is compared with other pre-trained CNN such as Visual Geometry Group16 (VGG16), VGG19, GoogLeNet, AlexNet, and ResNet50. Among these networks, the deep ResNet101 architecture has achieved the highest accuracy of 94.6%. Finally, a case study has been conducted based on the estimated severity levels and the required fungicide treatment is also prescribed.

Diversity of fungal isolates associated with early blight disease of tomato from mid Himalayan region of India

Tomato (Solanum lycopersicum L.), is an important horticulture crop supporting rural economy of Sirmaur district of Himachal Pradesh. Tomato crops in this geographical region are highly susceptible to plant pathogens resulting in significant loss of productivity and yield. In this study, we have determined the prevalence and causative pathogens of early blight disease affecting tomato crops in 18 geographical sites of district Sirmaur. On the basis of colony characteristics, microscopic features and ITS region sequence-based phylogenetic analysis, blight disease-associated isolates exhibited close resemblance to Alternaria alternata and other related species. These findings necessitates an integrated management strategy for effective pathogen control towards minimising the crop losses.

The effective antagonistic potential of plant growth-promoting rhizobacteria against Alternaria solani-causing early blight disease in tomato plant

Tomato plants can be infected by several diseases, among them, the early blight disease, caused by the necrotrophic fungus Alternaria solani is very dangerous. Plant growth promoting rhizobacteria (PGPR) are enhanced the plant growth and suppress plant diseases. The current study was conducted in a pot experiment to investigate the bio-efficacy antagonistic bacterial isolates as either individual or combination against tomato early blight disease. Disease severity and protection percent, morphological indicators as well as yield characters were recorded. In vitro antagonistic activity assay of PGPR against A. solani was estimated. Metabolic indicators of resistance in plant as response to induction of systemic resistance (ISR) were recorded. Our results indicated that, PGPR isolates were reduced the percent disease severity by 13.0 % and recorded highly protection percent by 84.3 %. The beneficial effects of the used elicitors were extended to increase not only the morphological characters (shoot lengths, root lengths and leaflet number/plant) but also the yield characters. All tested elicitors caused the marked significant increases in the photosynthetic pigments. PGPR isolates were exhibited the most potent effect in terms of the contents of chlorophyll a, b and the total chlorophyll (a + b) followed by plants treated with A. xylosoxidans (A3), B. subtilis (B1) and L. fusiformis (L2) in the infected plants, compared to the non-treated infected control. PGPR isolates were increased total phenol (56.15 mg/100 g dry wt.), free proline (1.435 mg/g dry wt.), total protein (1.198 mg/g dry wt.) and the activities of peroxidase (0.705 μg/100 g fresh wt.) and polyphenol oxidase (1.281 μg/100 g fresh wt.). All the tested treatments resulted in increasing the contents of indole acetic acid (IAA), Abscisic Acid (ABA), Salicylic Acid (SA), and Jasmonic acid (JA) compared with those of the infected plants. PGPR isolates’ antifungal activity may be attributed to cell wall disruption of A. solani and the normal conidial development inhibition. Therefore, due to these outstanding properties of PGPR isolates as plant growth promoters and antifungal activity, this study could give insights for solving serious agricultural challenges and particularly in the treatment of A. solani invasion across the tomato plants.

Effect of different dates of planting and weather parameters on early blight disease of tomato

Effect of different dates of planting and weather parameters on early blight disease of tomato

Evaluation of bio-efficacy and phytotoxicity of BAS 751 01 F SC against early blight disease of tomato

Early blight disease in tomato is destructive in nature and reduces fruit yield. Fungicides were used to control early blight disease but still early blight disease occurs. Hence, for in search of good alternative fungicide to control early blight disease, field experiment on efficacy of BAS 751 01 F SC against early blight disease was conducted in kharif season of 2017-18 and 2018-19. There were 7 treatments with six fungicides and control. Observations on per cent disease index (PDI), fruit yield and phytotoxicity of fungicides on tomato were recorded. In both 2017-18 and 2018-19, BAS 751 01 F SC with a.i.(g) of 200 @ 500 ml or g/ 500 – 750 litres of water was found superior in reducing disease severity (22.12 % mean PDI) over other fungicides used. In 2017-18 and 2018-19, BAS 751 01 F SC with a.i.(g) of 200 @ 500 ml or g/ 500 – 750 litres of water treated plants produced higher yield of tomato fruits (19.41 t/ha, 19.80 t/ha) over other fungicides. BAS 751 01 F SC with a.i.(g) of 200 @ 500 ml or g/ 500 – 750 litres of water were not toxic to tomato plant in kharif season of 2017-18 and 2018-19. The results concluded that use of BAS 751 01 F SC with a.i.(g) of 200 @ 500 ml or g/ 500 – 750 litres of water resulted in reducing disease severity and improved yield.

SPATIAL DISTRIBUTION OF EARLY BLIGHT DISEASE ON TOMATO, CLIMATIC FACTORS AND BIOEFFICACY OF PLANT EXTRACTS AGAINST Alternaria solani

Information on the spatial variability in plant disease is essential for location-based disease management. In the current study, the spatial distribution of tomato early blight disease was ascertained in District Gilgit, GilgitBaltistan, Pakistan. The comprehensive field survey was carried in two growing seasons (2014–2015), whereas in each growing season, 62 tomato fields were surveyed. Based on the distribution of disease, the respective thematic maps (incidence and severity) were prepared using Arc Map 10.1 with spatial analyst function of Arc GIS software by means of the inverse distance weight (IDW) interpolation method. Results indicate that early blight of tomato is spatially distributed in both growing seasons. However, in the first growing season, the disease incidence ranged from 10.22% to 44.16% and during later season 14.03–49.16%, whereas 5.37–16.40% and 6.52–26.94% severity was recorded. Furthermore, this information indicates that higher disease infestation occurred in 2015 in relation to 2014. This information linked to metrological data (temperature, precipitation and relative humidity), seemingly favored the early blight development during the growing period. Seven botanical extracts were tested against pathogen Alternaria solani at different concentrations (4, 6 and 8%). Results revealed that all tested plant extracts showed antifungal activities. However, at 8% concentration of plant extract, Datura starmonium, Berberis orthobotry, Podophyllum emodi and Uretica dioica exhibited >60%, while Peganum harmala, Artemisia maritima and Capparis spinosa <60% antifungal properties. The information generated due to this study could help the tomato growers regarding disease management and selection of resistant cultivars, improving profitability and food security in the Gilgit region.

Combating early blight infection by employing Bacillus subtilis in combination with plant fertilizers

In sustainable agriculture, integrated plant nutrition management along with a biological agent is an imperative module as a cost-effective and eco-friendly approach against drastic plant hackers (phytopathogens). Bacillus subtilis is one of the most potential biological control agents, because of the broad-spectrum activity of their antibiotics. The current study was carried out to explore in vivo biocontrol efficacy of Bacillus subtilis alone and in combination with plant nutrients [NPK, Zn (1X & 2X), Mg and B] against early blight disease of tomato caused by the necrotrophic fungus Alternaria solani. Results revealed that foliar application of B. subtilis alone and in combination with the plant nutrients managed EB disease significantly by 67–83%, while improved plant growth attributes by 20–77%. B. subtilis and plant nutrients helped the tomato plant to fight off the plant hacker by up-regulating the production of total phenolic contents and defensive enzymes (phenylalanine ammonia-lyase, superoxide dismutase, catalase, peroxidase, and polyphenol oxidase). In the current investigation, the light was shed on the interactive effect of microbial agent and positive consequences on plant mineral uptake. It was concluded that integrative use of NPK and Zn (2X) along with B. subtilis have a synergistic impact to manage the disease, improve plant growth, and optimistically enhance physiological and biochemical attributes to contest EB stress in tomato plants.

Effect of Nano-Chitosan on Early Blight Disease of Tomato

Effect of Nano-Chitosan on Early Blight Disease of Tomato

Prediction of Tomato Early Blight Disease Under Climate Change Conditions in Egypt

Early blight caused by Alternaria solani (Ell. and Mart.) is one of the most important economic diseases, which caused considerable loss in their yield and quality under Egyptian conditions. Aim the research was to study the relationship between climate change and disease severity for prediction in future seasons. Disease severity was recorded for three growing periods i.e. summer (May. to Aug), autumn (Jul. to Oct) and winter (Nov. to Mar.), at three governorates (Behira, Ismailia, and Assuit) during growing seasons 2016/2017-2017/2018. Severity of early blight disease on tomato has been predicted by regression estimated accumulative disease severity values during 2007/2008 to 2015/2016 season and average max and min temperature and humidity through these seasons. Prediction of disease has been formed as Y= b0+b1x1+b2x2+ bqxq. Three models were created to describe the severity disease by multiple regressions (MINITAB® program). The highest value of early blight disease was recorded through season 2017/2018, while the lowest value was recorded during season 2016/2017. Also, highly disease severity was estimated during summer period compared with autumn and winter growing periods, but through winter growing period was the least severity and moderately severity estimated in the autumn growing period. Influence of environmental conditions on the severity of early blight disease during seasons from 2007/2008 to 2015/2016, in Behira governorate, the highest disease severity was showed in season 2010-2011, and the lowest disease was in season 2012-2013, but in Ismailia governorate, highest disease severity was estimated in season 2010-2011and lowest disease was recorded in season 2013-2014 and in Assuit governorate, the highest value of disease was in season 2010-2011, and the lowest value was in season 2013-2014. For Forecasting, significantly differences noticed between disease severity through 2020/2030, 2030/2040 and 2040/ 2050s seasons compared with 2008/2018s seasons and thier relation with climate change in tested governorates, where severity of tomato early blight disease was icreased from 11.8% during 2008/2018s seasons to 2040/ 2050s seasons 15.4% during at Behira governorate, from 18.8% during 2008/2018s seasons to 2040/ 2050s seasons 36.3% during at Ismailia governorate and from 18.8% during 2008/2018s seasons to 2040/ 2050s seasons 40.4% during at Assuit governorate with slight change in maximum or minimum temperatures and percentage of relative humidity.

Genetic defense analysis of tomatoes in response to early blight disease, Alternaria alternata

Early blight disease of tomato is one of the most devastating biotic stresses worldwide, and in Iran, Alternaria alternata is one of the most predominant species causing the disease. In the current study, a diverse collection of 35 tomato genotypes and implication of 5 SlWRKYs and 7 PR genes as well as enzymatic activity were evaluated on resistant and susceptible cultivars through real-time polymerase chain reaction at transplanting and maturing stages and by measuring product formation using spectrophotometry. The results indicated that the expression of these antifungal genes in 14 genotypes at two growth stages after inoculation with A. alternata highly enhanced by 1–50-fold. There was also significant upregulation of WRKYs and PRs genes among the resistant tomato varieties in comparison to susceptible and control varieties at both stages. These findings demonstrate the varieties that showed increased or decreased SlWRKY1 expression also displayed similar changes in the expression of PR1 and PR2 genes. Furthermore, the differential expression patterns of SlWRKY1 and SlWRKY11 were consistent with PR7 and PDF1.2 expression patterns. The analysis of enzymatic activity of PR2 and PR3 proteins, β-1,3-glucanase, and chitinase showed the highest level of activity in resistant inoculated genotypes against A. alternata. Therefore, the current findings suggest the possible involvement of these transcription factors in the increased expression of PR genes in response to A. alternata infection.

Estimation of secondary metabolites of indigenous medicinal plant extracts and their in vitro and in vivo efficacy against tomato early blight disease in Pakistan

Fifteen Pakistan’s indigenous medicinal plant extracts were investigated for various secondary metabolites and their potential against tomato early blight disease. In vitro screening of aqueous and methanolic extracts of fresh and dry plant parts was performed against Alternaria solani at 20, 40, 60 and 80% concentrations, by mycelial inhibition measurement through food poison technique. The aqueous extracts of Azadirachta indica, Allium sativum and Ocimum sanctum showed significant antifungal activity at all tested concentrations. Aqueous extract of fresh plant material was found more effective than that of dry plant material and the methanolic extracts of fresh or dry plants. Phytochemical analysis of extracts revealed that the antifungal potential was directly related to the type and quantity of secondary metabolites. The highest phenolics were recorded from A. indica (56.43 mg gallic acid equivalent (GAE)/g) followed by A. sativum (54.25 mg GAE/g) and O. sanctum (53.38 mg GAE/g), respectively. The aqueous extracts of fresh A. indica, A. sativum and O. sanctum were also found effective when applied to plants grown in greenhouse and field. A. indica extracts reduced disease incidence to 62.32%, in the greenhouse increasing the yield up to 138 g/plant over control (94.33 g/plant), while in the field experiment A. sativum showed highest reduction in disease incidence to 77.42% with an increasing yield up to 3.70 t/ha compared to control (2.43 t/ha). The results of this study indicate that aqueous extracts of fresh A. indica, A. sativum and O. sanctum have great potential to be used to control early blight disease of tomato in the field.

Inhibition of Tomato Early Blight Disease by Culture Extracts of a Streptomyces puniceus Isolate from Mangrove Soil.

This study investigates the potential of natural products derived from a mangrove rhizosphere bacterium in tomato early blight management. A Streptomyces puniceus strain L75 was isolated from the rhizosphere of Acanthus ilicifolius Linn in the Mai Po Reserve, Hong Kong. The crude ethyl acetate (EA) extract of L75 fermentation cultures has broad-spectrum antifungal bioactivities. L75 EA extract was significantly more effective in Alternaria solani growth inhibition at 25 μg/ml or lower compared with Mancozeb, with no observable negative impacts on tomato leaves or root development. Furthermore, L75 EA extract had significantly lower aquatic toxicity than Mancozeb at the same concentrations. L75 EA extract targets germ tube elongation of A. solani conidia, with a fungistatic mode of action. Liquid chromatography-quadrupole time-of-flight mass spectrometry analysis identified two possible antifungal compounds, Alteramide A and the Heat-Stable Antifungal Factor, which together contribute partially to the bioactivity of L75 EA extract. On detached tomato leaves, coinoculation of A. solani with L75 EA extract of 50, 25, or 5 μg/ml reduced diseased areas by ∼98, ∼90, and ∼48%, respectively, relative to the control after 5 days. This study demonstrates the potential of natural products from mangrove rhizosphere bacteria in agricultural applications.

Intervention of antagonistic bacteria as a potential inducer of disease resistance in tomato to mitigate early blight

Early blight (EB), caused by Alternaria solani, is one of the major threat that limiting tomato production globally. Microbial biopesticides derived from bacteria have the potential to produce a wide range of antifungal metabolites with remarkable biocidal effects. In vitro screening with twenty bacterial strains was carried out by a dual-culture assay, amongst three strains of Bacillus subtilis (BS-01, BS-02 and BS-03), one each of Pseudomonas maltophilia (PM-01) and Azospirillum brasilense (AB-01) were selected as potential antagonists for in vivo assay. Results of pot experiment revealed that foliar application of antagonists significantly managed EB disease by 42–92% with a notable reduction in disease percent severity index by 10–60% and improved the plant growth attributes by 25–165%. Induction of resistance in tomato plant was triggered by up regulation of antioxidant enzymes viz., catalase, peroxidase and polyphenol oxidase along with the high production of total phenolics. Biocontrol efficacy on tomato fruit indicated that BS-01 also proved effective in managing percent infection severity by 60%. The results of current investigation suggested that BS-01 (B. subtilis) was found to be as an excellent resistance inducer in plants that could be used as biopesticides as a prospective management tool against EB disease of tomato.

Evaluation of Some Antioxidants against Tomato Early Blight Disease

Evaluation of Some Antioxidants against Tomato Early Blight Disease