Blight Of Tomato Research Articles

A Novel Rhizospheric Bacterium: Bacillus velezensis NKMV-3 as a Biocontrol Agent Against Alternaria Leaf Blight in Tomato.

A novel strain of Bacillus isolated from rhizosphere has shown to be an excellent biocontrol agent against various plant pathogens. In this study, a first report of a Bacillus strain NKMV-3 which effectively controls Alternaria solani, which cause the early blight disease in tomato. Based on the cultural and molecular sequencing of 16S rRNA gene sequence, the identity of the strain was confirmed as Bacillus velezensis NKMV-3. The presence of the lipopeptide which are antibiotic synthesis genes, namely iturin C, surfactin A and fengycin B and D, was confirmed through gene amplification. In addition, lipopeptides were also confirmed through liquid chromatography. The extract showed inhibitory effect against A. solani in vitro and detached tomato leaf assays. Bacillus velezensis strain NKMV-3-based formulations may provide an effective solution in controlling early blight disease in tomato and other crops.

English

The current research was conducted to investigate the alterations in the mineral status in the leaves of tomato plants against early blight (EB) caused by Alternaria solani. Six tomato varieties; viz. Riograndae, Roma and Basket (resistant) and T-88572, BHN-961 and BHN-1021(susceptible) were inoculated with a blend of five isolates of Alternaria solani, collected from different regions of Faisalabad District. These six varieties for mineral profiling were selected after two years screening from twenty-five varieties of tomatoes under field conditions. These varieties were sown in pots and artificial inoculation was performed to develop disease in inoculated type of tomato plants while distilled water was applied on un-inoculated type of plants. Newly infected leaves from upper, middle and lower parts of tomato plants from resistant and susceptible groups were used to prepare sample for mineral analysis at p ≤ 0.05 and variation in mineral profiling of resistant and susceptible groups of tomato plants was determined through Nested Structured Design. Significant variation was observed in inoculated (3.12, 0.48 %, 1.17, 0.14, 0.42, 0.21, 0.69 and 1.49 ppm and un-inoculated type (8.67, 1.61%, 10.45, 0.22, 1.75, 1.98, 3.09 and 3.39 ppm) while resistant group expressed 6.59, 1.19%, 8.13, 1.973, 1.69, 1.26, 1.36, 2.43 and 2.87ppm and susceptible group exhibited 5.19, 0.91%, 5.69, 1.693, 1.24, 0.91,0.83, 1.35 and 2.22 ppm with respect to NPK, Ca, Mg, Na, Zn, Iron and copper. Resistant variety, Riograndae expressed maximum amount while T-88572 exhibited minimum amount of all mineral contents. Alterations in the mineral profiling in leaves of tomato plants can be used by researchers as biochemical markers for identification and development of resistant source against early blight of tomato and for the development of ecofriendly management strategy towards A. solani.

Benzoic Acid and Its Hydroxylated Derivatives Suppress Early Blight of Tomato (Alternaria solani) via the Induction of Salicylic Acid Biosynthesis and Enzymatic and Nonenzymatic Antioxidant Defense Machinery.

Tomato early blight, caused by Alternaria solani, is a destructive foliar fungal disease. Herein, the potential defensive roles of benzoic acid (BA) and two of its hydroxylated derivatives, ρ-hydroxybenzoic acid (HBA), and protocatechuic acid (PCA) against A. solani were investigated. All tested compounds showed strong dose-dependent fungistatic activity against A. solani and significantly reduced the disease development. Benzoic acid, and its hydroxylated derivatives, enhanced vegetative growth and yield traits. Moreover, BA and its derivatives induce the activation of enzymatic (POX, PPO, CAT, SlAPXs, and SlSODs) and non-enzymatic (phenolics, flavonoids, and carotenoids) antioxidant defense machinery to maintain reactive oxygen species (ROS) homeostasis within infected leaves. Additionally, BA and its hydroxylated derivatives induce the accumulation of salicylic acid (SA) and its biosynthetic genes including isochorismate synthase (SlICS), aldehyde oxidases (SlAO1 and SlAO2), and phenylalanine ammonia-lyases (SlPAL1, SlPAL2, SlPAL3, SlPAL5, and SlPAL6). Higher SA levels were associated with upregulation of pathogenesis-related proteins (SlPR-1, SlPR1a2, SlPRB1-2, SlPR4, SlPR5, SlPR6), nonexpressor of pathogenesis-related protein 1 (SlNPR1), and salicylic acid-binding protein (SlSABP2). These findings outline the potential application of BA and its hydroxylated derivatives as a sustainable alternative control strategy for early blight disease and also deciphering the physiological and biochemical mechanisms behind their protective role.

Effect of nutrients and plant extracts on Alternaria blight of tomato caused by Alternaria Alternata

Effect of nutrients and plant extracts on Alternaria blight of tomato caused by Alternaria Alternata

In-vitro Evaluation of Fungicide Sensitivity of Tomato Leaf Blight Pathogens

Tomato early and late blight diseases caused by Alternaria solani and Phytophthora infestans respectively, are constraints to tomato production globally. Conventional use of commercial synthetic fungicides in management of tomato blight disease has become a key input for tomato production among farmers in Tharaka Nithi County, Kenya. Indiscriminate use and application of sub-lethal doses of fungicides negate disease management efforts, and may lead to gradual fungicide resistance. Yet, local tomato farmers have continued to use the fungicides without periodic evaluation of their effectiveness. This study was carried out in-vitro to evaluate the efficacy of six synthetic commercial fungicides used by farmers around River Ruguti, against two tomato leaf blight pathogens; Alternaria solani and Phytophthora infestans. The poison food method was used to evaluate fungicides known by trade names and application levels; Mancozeb (640 g kg-1) + Metalaxyl (40 g kg-1), Mancozeb 640 g/kg + Metalaxyl 80 g/kg, Mancozeb, Propineb700 g/kg + Cymoxanil 60 g/kg, Carbendazim and Triticonazole at different concentration (25%, 50% and 75%). The in-vitro plate experiment was laid out in a Complete Randomized Design with 3 replicates, and data on mycelia growth inhibition analyzed through General Linear Model (α=.05) and significant means separated using Least significant difference (LSD) using Scientific Analysis System version 9.4. All the tested fungicides significantly (p≤ 0.05) inhibited mycelial growth of tested pathogen. Percentage inhibition for early blight pathogen (Alternaria solani) was 80.42% compared to late blight pathogen Phytophthora infestans at 69.51%. Mancozeb (640 g kg-1) + Metalaxyl (40 g kg-1) and Propineb700 g/kg + Cymoxanil 60 g/kg recorded higher per cent inhibition of mycelia growth of 92.4% and 89.71% respectively. Carbendazim recorded lower per cent inhibition of 39.15%. Mycelia growth inhibition increased with an increase in fungicide concentration. Lower inhibition of 71.78% was observed at 25% concentration as compared to 50% and 75% with 76.77% and 76.36% respectively. Fungicides screened varied in mycelia inhibition against P. infestans and A. solani isolates with Mancozeb (640 g kg-1) + Metalaxyl (40 g kg-1) and Propineb700g/kg +Cymoxanil 60g/kg giving significantly (p≤ 0.05) better inhibition while Carbendazim had the lowest inhibition effect. Increased fungicide concentration effectively inhibited mycelia growth. Thus higher concentration of fungicide application is recommended in cases where there is low efficacy of fungicides.

Antifungal activity and control of the early blight in tomato through tea tree essential oil

One of the main leaf diseases of tomato is the early blight, caused by the fungus Alternaria solani. The use of essential oils could be an alternative for controlling by acting plant defense against phytopathogens. The objective was to evaluate the antifungal, the early blight control, and the activity of defense enzymes in tomato treated with tea tree (Melaleuca alternifolia) essential oil. Aiming to evaluate the mycelial growth and sporulation of the pathogen, mycelial discs were placed in Petri dishes with 0, 500, 1000, 1500, 2000, and 2500 μL L−1 of essential oil, and an additional treatment with fungicide (azoxystrobin + diphenoconazole). The treatments were applied onto the second pair of leaves of tomato plants grown in a greenhouse, and after three days the pathogen was inoculated in the second and third pairs of leaves. Severity was expressed through the area under the disease progress curve (AUDPC). The peroxidase, polyphenoloxidase and phenylalanine ammonia-lyase activities were evaluated with the concentration of 1500 μL L−1. Mycelial growth showed a linear decrease as concentrations increased. In the treated leaves, the 1500 μL L−1 concentration showed the most reduction in AUDPC, corresponding to 53%, whereas in the untreated leaves, the most effective concentration was 2000 μL L−1 with 42% inhibition. An increase in peroxidase and phenylalanine ammonia-lyase activities were observed in the tomato leaves. Tea tree essential oil can be an alternative for the control of early blight in tomato.

Late blight in tomato: insights into the pathogenesis of the aggressive pathogen Phytophthora infestans and future research priorities.

This review provides insights into the molecular interactions between Phytophthora infestans and tomato and highlights research gaps that need further attention. Late blight in tomato is caused by the oomycota hemibiotroph Phytophthora infestans, and this disease represents a global threat to tomato farming. The pathogen is cumbersome to control because of its fast-evolving nature, ability to overcome host resistance and inefficient natural resistance obtained from the available tomato germplasm. To achieve successful control over this pathogen, the molecular pathogenicity of P. infestans and key points of vulnerability in the host plant immune system must be understood. This review primarily focuses on efforts to better understand the molecular interaction between host pathogens from both perspectives, as well as the resistance genes, metabolomic changes, quantitative trait loci with potential for improvement in disease resistance and host genome manipulation via transgenic approaches, and it further identifies research gaps and provides suggestions for future research priorities.

Potential, Challenges and Strategies Involved in Gene Introgression from Wild Relatives of Vegetable Crops: A Review

Wide hybridization is an important plant breeding method as it helps in broadening the gene pool of a crop when the desired variation is not sufficient or absent within the same gene pool. Wild genetic resources are the potential source of desirable genes for various characters of crop plants. It plays a significant role in transferring traits of interest like disease and insect resistance, improved quality, earliness, dwarfness, increased yield, abiotic stress tolerance and manipulation in mode of reproduction etc. in crop plants. It has been instrumental in transferring disease resistance from wild species into many vegetable crops. For example, resistance to late blight, leaf roll and potato virus X, yellow vein mosaic virus and powdery mildew in okra, bacterial wilt, tomato leaf curl virus, early and late blight in tomato has been transferred from wild species into cultivated species. Wild species has been used to improve the quality traits of some crops like carotenoid content in carrot and tomato, starch content in potato etc. Sometimes distant hybridization leads to creation of entirely new crop species. Chromosome elimination technique followed by wide hybridization has been successfully used in the production of double haploids in some crops. However there are some lacunae in wide hybridization such as cross incompatibility, hybrid inviability, hybrid sterility and hybrid breakdown. Some special techniques viz. ploidy manipulation, pistil manipulation, growth regulators treatments, bridge crossing, grafting and embryo rescue have to be adopted to make distant hybridization successful in such cases.

Molecular and biochemical insight into biochar and Bacillus subtilis induced defense in tomatoes against Alternaria solani

This study was aimed to elucidate the biochar induced resistance pathways in association with beneficial plant growth promoting rhizobacteria (PGPR) in the tomato (Solanum lycopersicum) – Alternaria solani pathosystem. To examine the impact of biochar on plant defense mechanisms at the molecular level, tomato plants were grown in two different biochars (wood and green waste biochar; 3 and 6% application level of each) both with and without Bacillus subtilis, (PGPR). Although, the reduction in disease index and disease incidence was significant in wood biochar amended soil but the resistant plant response against early blight was only recorded in the 6% green waste biochar amended treatment. Biochar application has induced the expression of defense associated genes including jasmonic acid related PI2, TomloxD, salicylic acid related PR1a, PR2 and ethylene responsive Pti4. Green waste biochar (6%) was more efficient in eliciting the expression level of TomloxD, PI2, PR1a and PR2 in tomatoes challenged by A. solani, while PGPR inoculation has enhanced the PR2 expression levels in comparison to tomatoes grown in wood biochar amended soil substrate. Moreover, phenolics, catalase and peroxidase production levels of plants grown in green waste biochar alone as well as in the presence of B. subtilis, contributed significantly in moderating infection induced damages.In conclusion, tomatoes response to invading A. solani was dependent on the type of biochar, while protection against early blight was better at higher application rate of biochar i.e. 6%. Different biochar types also differ with their ability to elicit the defense gene expression/signaling pathways. Our study revealed that biochar and PGPR induced protection against early blight of tomatoes involves both induced systemic resistance (ISR) and systemic acquired resistance (SAR) mechanisms.

INFLUENCE OF VARIOUS MEDIA AND NUTRIENT SOURCES ON ALTERNARIA SOLANI CAUSE EARLY BLIGHT DISEASE IN TOMATO

Early blight of tomato (Solanum lycopersicum L.) incited by Alternaria solani is highly destructive causing yield loss up to 78 per cent. The fungus was tested with different media along with the host extract and different nutrient sources for their growth and development in in vitro. Twelve different media were tested on the growth of A. solani, among them potato dextrose agar + host leaf extract recorded maximum radial mycelial growth of A. solani (89.57mm) and potato dextrose broth + leaf extract has maximum mycelial dry weight (613mg). Six carbon and nitrogen sources amended media were tested. Among carbon sources, glucose recorded maximum radial mycelial growth (74.65mm) and mycelia dry weight (709.17mg). Among the nitrogen sources, ammonium nitrate has the enhanced the radial mycelail growth (84.56 mm) and high mycelial dry weigh (654.27mg). This study will be helpful for further investigations on the physiology of the fungus and management of the disease.

Rhizopus spp Promoting and Inducing Late Blight (Phytophthora infestans) Resistance in Solanum lycopersicum L.

Tomato (Solanum lycopersicum L) which is highly consumed by humans, suffer severe attacks of various pathogens. Among these pathogens, Phytophthora infestans is the most prominent causing a devastating tomato disease called late blight. This study was aimed at evaluating the protective effects of Rhizopus spp on tomato plant growth upon infection with P. infestans. The work was partition into two phases: phase 1 delt with the effect of Rhizopus spp on tomato growth parameters while phase 2 was on the protective effects of Rhizopus spp against late blight in tomato and its attributes on biochemical parameters. In phase 1 seedlings were raised and divided into five groups of six plants each. Group I was the control while Groups II to V were treated with Rhizopus spp (2.5; 5.0; 7.5 and 10.0 mg/ml respectively) for 25 days. After every 5 days’ plants were treated and on each day of treatment, growth parameters (number of leaves and height) and chlorophyll contents measured. On day 25, samples were collected for biochemical analysis (flavonoids, phenolic content, total protein, vitamin C, catalase (CAT), reduced glutathione (GSH)). In phase 2, Rhizopus at 5 mg/ml obtained as best results in phase one was used. Raised seedlings were divided into four groups: Group 1 was healthy (H), Group 2 of plants infected with P. infestans (50 mg/ml) (I), Group 3 of plants stimulated with Rhizopus spp (5.0 mg/ml) (St), and Group 4 of plants inoculated with P. infestans after stimulation with Rhizopus spp (St + I) for 7days. Every two days, diseases incidence and severity were recorded and after 10th days samples were collected for biochemical (total protein, CAT and GSH) analysis. As results, Rhizopus spp inoculation induced an increase in the number of leaves, plant height and chlorophyll contents compared to the control group with plants of group II (Rhizopus spp 5.0 mg/ml) having the best result. A significant increase (p< 0.05) in flavonoid, phenolic content, reduced glutathione level and catalase activity were recorded. Another significant increase (p< 0.05) in disease incidence and severity in plants treated with the pathogen when compared to the control. Co-inoculation of plants with Rhizopus spp and P. infestans significantly decreased disease incidence and severity. Also a significant decrease in GSH level and CAT activity were noticed. Co-inoculation of plants with Rhizopus spp and P. infestans significantly increased (p< 0.05) GSH level and CAT activity when compared to the control group. In conclusion Rhizopus spp instigate plant growth and induce disease resistance in tomato upon infection with P. infestans causing late blight.

Potential of Trichoderma spp., Bacillus subtilis and Pseudomonas fluorescens in the management of early blight in tomato

ABSTRACT Early blight is a common challenge to tomato production all over the world. Microbial antagonists, unlike synthetic chemicals, are friendly to the environment and human health. In this study, five microbial antagonists were evaluated for their effectiveness in managing the early blight of tomatoes under greenhouse and field conditions. Microbial antagonists included two Trichoderma isolates, two Bacillus subtilis isolates and one Pseudomonas fluorescens isolate. Water and Tower 72 WP® were used as control and reference test, respectively. Data were collected on disease parameters and tomato yield. All treatments significantly reduced the per cent disease index compared to the control in the greenhouse and in the field. The per cent disease index recorded for Tower 72 WP® was comparable to the per cent disease index recorded for most selected antagonists. All treatments recorded significantly higher yields compared to the control in the greenhouse and in the field. Trichoderma isolates and Tower 72 WP® recorded the highest tomato yields in the greenhouse. Selected microbial antagonists were effective in managing early blight in tomato under greenhouse and field conditions and minimised yield losses caused by the disease. These should be integrated in the management of early blight of tomatoes to reduce the dependence on agrochemicals.

Pathological Survey on Early Leaf Blight of Tomato and In Vitro Effect of Culture Media, Temperature and pH on Growth and Sporulation of Alternaria solani

Alternaria solani causing early blight of tomato is a serious disease, causing 50% to 86% losses in fruit yield and 20% to 40% losses in seedling establishment. Pathological survey, etiology and physiological characterization of the causal organism are necessary to formulate effective management strategy. Therefore, present study was conducted to determine the incidence and severity of early leaf blight of tomato in some selected area of Bangladesh and to evaluate the effect of different culture media on radial mycelial growth and sporulation as well as the effect of pH and temperature on mycelial growth. Survey was conducted in five upazilas of Bogura district and typical early blight disease sample was collected from surveyed field and Germplasm Centre, Agrotechnology Discipline, Khulna University, Khulna. Seven different culture media were used namely Potato Dextrose Agar (PDA), Richard’s Agar (RA), Waskman Agar (WA), Corn meal Agar (CA), Asthana and Hawker’s Agar (AHA), Oat Meal Agar (OMA), V-8 Juice Agar Medium (VJAM) and seven different pH level such as 5.0, 5.5, 6.0, 6.5, 7.0, 7.5 and 8.0 were used and also exercised five distinct temperatures such as 20°C, 25°C, 30°C, 35°C and 40°C to appraise cultural characters, mycelial growth and sporulation of A. solani. Cultural characters such as colony color, colony diameter, growth margin, growth surface and margin topography showed distinguished variation in culture media. Among the seven different media V-8 Juice Agar Medium gave not only maximum mycelial growth (73.10 mm) but also highest sporulation (2000 spores ml?1). The optimum pH for maximum mycelial growth ranged to 5.5 - 6.5. But maximum mycelial growth (71.70 mm) was observed in pH 6. Whereas, the mycelial growth was favored by 20°C - 30°C temperature but 25°C temperature provided highest mycelial growth (72.20 mm). However, temperature above 40°C was found adverse for the growth of tested fungus.

Antimicrobial activity of essential oils against early blight of tomato under in vitro conditions

Fungal diseases limit tomato production, particularly the early blight caused by Alternaria solani. Disease control is usually done with synthetic fungicides, which have long-term residual effects and also contribute to environmental pollution. In this study, the effectiveness of essential oils from lemongrass (Andropogon citratus), citronella oil (Cymbopogon nardus), clove oil (Syzygium aromaticum), peppermint oil (Mentha piperita) and patchouli oil (Pogostemon cablin) were tested in vitro in suppressing the radial growth of A. solani. The suppression of fungal growth was determined by measuring the radial growth of the examined pathogen. The oils have shown a certain effectiveness against the pathogen in question. Lemongrass oil was found to be the best oil for disease suppression at concentrations of 0.02%, 0.06%, 0.1% (59.37%, 73.12% and 84.32%, respectively). Essential oils were equally effective as synthetic fungicides in limiting pathogen growth. However, for these products to be used effectively in agricultural fields, an industrial formulation may be required to increase their effectiveness.

Mycomolecules against Alternaria solani causing Early blight of tomato

Mycomolecules isolated from mushroom possess antimicrobial properties which forms bioactive compounds of high therapeutic and pharmacological value. Antimicrobial principles from macro basidiomycetes against plant pathogens was not yet well explored. In this view, a study was proposed to screen mushroom fungi viz., Lentinus edodes, Volvariella volvaceae, Ganoderma lucidum and Auricularia polytricha against tomato early blight pathogen Alternaria solani. Methanol extracted mycomolecules from the cell free culture of mushroom was used in different experiments of the study. Results from dual culture technique revealed that Ganoderma lucidum showed maximum antifungal activity by inhibiting the mycelial growth of A. solani (67%). Among the various mushroom fungi, G. lucidum cell free culture filtrates exhibited maximum inhibition of spore germination of A. solani (53%) at 24 hours. The methanol extracted metabolite fractions of G. lucidum at 0.2% concentration inhibited maximum mycelial growth of A. solani (69%). Results indicates that methanol extracted cell free culture fractions of G. lucidum possess antifungal activities against the growth of A. solani and these mycomolecules could be further explored for the development of fungicides against the pathogen.

Effect of pulsed magnetic field on seed borne pathogen and germination of tomato

Effect of Pulsed Magnetic Field (PMF) treatment on the control of Alternaria solani (Ellis and Martin) Jones and Grout causing Early blight of tomato (Solanum lycopersicum L.) cultivar PKM 1 was studied. The seeds pre-inoculated with A. solani were 1500nT PMF treated with frequency of 10 Hz for 5 h for varied durations of 0, 5, 10, 15, 20 and 25 days. PMF treatment significantly reduced pathogen incidence and increased both germination and plant growth in comparison with the control. Experimental results indicated that all the treatments were significantly different and the seeds treated for 20 and 25 days showed the minimum percent disease incidence (71%) with highest percent disease inhibition over control (29%). It also recorded the highest plant biometrics viz., germination (81%), speed of germination (7.74), root length (13.37 cm), shoot length (6.45 cm) and vigour index (1606). Control recorded the minimum plant biometrics viz., germination (61%), speed of germination (7.27), root length (12.92 cm), shoot length (6.17 cm) and vigour index (1164).

Evaluation of Essential Oils against Early Blight (Alternaria solani) of Tomato

The fungicidal effect of some essential oils viz., Neem, Eucalyptus, Pongamia, Lemongrass, Thyme and Clove were evaluated against Alternaria solani causing early blight of tomato resulting in severe yield loss. All essential oil treatments showed the significantly varied antifungal activity against the pathogen. Among the in-vitro screened essential oils percent growth inhibition of pathogen was higher in Thyme oil (80%) and it was followed by Clove oil and Eucalyptus oil. Plant biometric observations viz., seed germination (84%) and seedling vigor (1747) was maximum with lower percent disease index (13%) was recorded in Thyme oil treated seeds and seedlings of tomato cultivar PKM 1.

Efficacy of modern fungicides against tomato alternaria blotch

Goal. To determine the species composition of early blight on tomatoes and to establish the technical effectiveness of modern fungicides.
 Methods. The research was conducted in 2019—2020 in Cherkasy, PE «Poretsky» on tomatoes variety Zagadka. Weather conditions of the growing season favored the intensive disease development. Plot size — 10 m2 in 4 replicates, placement of plots — randomized. Agricultural techniques are common for the growing area. To determine the species composition of pathogens, during the growing season samples of plants with typical symptoms were taken. Isolation of phytopathogen in pure culture and their identification was carried out in the laboratory according to conventional methods. To determine the technical effectiveness of fungicides the following fungicides were used: Zorvek Incantia, SE (0.5 l/ ha), Orvego, KS (1.0 l/ha), Quadris 250 SC, hp (1.0 l/ha), Quadris Top 325 SC, KS (0.6 l/ha), Cabrio Duo, KE (2.5 l/ha), Signum, VG (0.3 kg/ha), Thanos 50, VG (1.0 kg/ha).
 Results. As a result of research, it was found that during the growing season early blight was the most common. According to our research, the disease is caused by two species of the pathogen Alternaria alternata (Fr.) Keissl. and Altrenaria solani Sorauer. We found that almost 70% of isolated and identified isolates were classified as Alternaria solani. For protecting of tomatoes against early blight following fungicides were used: Zorvek Inkantiya, CE (0,5 l/hectare), Orvego, KS (1,0 l/h), Kvadris 250 SC (1.0 l/ hectare ), Kvadris Top 325 SC (0.6 l/h), Kabrio Duo, KE (2.5 l/h), Signum, VG (0.3 kg/h), Tanos 50, VG (1.0 kg/h). Technical efficiency of them was 55.6—78.6%, and the stored harvest — 5.11—6.62 t/ha.
 Conclusions. As a result of researches we specified specific composition of early blight of tomatoes. It is set that disease is caused by two species: Alternaria alternata and Alternaria solani, that are different in anatomo-morphological properties. It is established that to protect tomatoes from Alternaria, it is advisable to apply the following fungicides: Kvadris 250 SC (1.0 l/h), Kvadris Top 325 SC (0.6 l/h), Kabrio Duo, KE (2.5 l/h).

Fragments of a Wheat Hevein-Like Antimicrobial Peptide Augment the Inhibitory Effect of a Triazole Fungicide on Spore Germination of Fusarium oxysporum and Alternaria solani.

There are increasing environmental risks associated with extensive use of fungicides for crop protection. Hence, the use of new approaches using natural plant defense mechanisms, including application of plant antimicrobial peptides (AMPs), is of great interest. Recently, we studied the structural–function relationships between antifungal activity and five hevein-like AMPs from the WAMP (wheat AMP) family of Triticum kiharae Dorof. et Migush. We first discovered that short peptides derived from the central, N-, and C-terminal regions of one of the WAMPs (WAMP-2) were able to augment the inhibitory effect of Folicur® EC 250, a triazole fungicide, on spore germination of the wheat pathogenic fungi, including Fusarium spp. and Alternaria alternata. In this research, we explored the ability of chemically synthesized WAMP-2-derived peptides for enhancing the sensitivity of two other Fusarium and Alternaria species, F. oxysporum and A. solani, causing wilt and early blight of tomato, respectively, to Folicur®. The synthesized WAMP-2-derived peptides synergistically interacted with the fungicide and significantly increased its efficacy, inhibiting conidial germination at much lower Folicur® concentrations than required for the same efficiency using the fungicide alone. The experiments on co-applications of some of WAMP-2-fragments and the fungicide on tomato leaves and seedlings, which confirmed the results obtained in vitro, are described.

Biocontrol agents against early blight (Alternaria solani) of tomato

Biological control agents are the best alternative to the hazardous chemical fungicides and other agro chemicals. Various biological control agents viz., Trichoderma viride, Pseudomonas fluorescens and Bacillus subtilis were evaluated against Alternaria solani (Ellis and Martin) Jones and Grout causing early blight of tomato resulting in severe yield loss. All treatments showed the varied antifungal activity against the pathogen. Among the in vitro screened biological control agents percent growth inhibition of pathogen was higher in Trichoderma viride (77%). Plant biometric observations viz., seed germination (89%) and seedling vigor (1994) was maximum with lower percent disease index (16%) was recorded in Trichoderma viride treated seeds and seedlings of tomato cultivar PKM 1.