Tomato Powdery Mildew Research Articles

Effectiveness of Different Fungicides in Combating Tomato Powdery Mildew in Karnataka

Field experiment was carried out to know the effect of different fungicides against powdery mildew of tomato during two Kharif seasons of the year 2022 and 2023. Among the nine treatments, combination fungicides were significantly (p<0.05) more effective than solo fungicides. Picoxystrobin 6.78% + Tricyclazole 20.33% SC applied at 2 ml/l achieved the lowest percent disease index (PDI) of 14% in the first season, with a 74.77% reduction over the control (55.50% PDI). This was closely followed by Azoxystrobin 18.2% + Difenoconazole 11.4% SC at 1.2 ml/l, which recorded a PDI of 14.50% and a 73.87% reduction. In the second season, similar trends were observed with Picoxystrobin 6.78% + Tricyclazole 20.33% SC achieving a PDI of 13.50% and a 74.53% reduction, followed by Azoxystrobin 18.2% + Difenoconazole 11.4% SC with a PDI of 14% and a 73.58% reduction. Pooled data from both seasons confirmed these findings, showing Picoxystrobin 6.78% + Tricyclazole 20.33% SC with a PDI of 13.75% and a 74.65% reduction, and Azoxystrobin 18.2% + Difenoconazole 11.4% SC with a PDI of 14.25% and a 73.73% reduction. The highest PDIs were noted in the Carbendazim 50% WP and Hexaconazole 5% SC treatments. The study highlights the inefficacy of relying on a single fungicide due to resistance development, suggesting combination fungicides as a more effective strategy for managing powdery mildew in tomatoes. It is possible advancing with broader integrated disease sustainable management strategies to protection of environment, crop protection and yield.

Predatory mites as potential biological control agents for tomato russet mite and powdery mildew on tomato

Predatory mites as potential biological control agents for tomato russet mite and powdery mildew on tomato

Simultaneous use of Beauveria bassiana and Bacillus subtilis-based biopesticides contributed to dual control of Trialeurodes vaporariorum (Hemiptera: Aleyrodidae) and tomato powdery mildew without antagonistic interactions

BackgroundImplementing pest and disease control techniques that have low environmental impact is important for sustainable agriculture. Microbial biopesticides are an effective approach due to their low environmental impact and low risk of resistance development. Because it is not usually possible to control multiple pests and diseases with a single microbial biopesticide, it is essential to investigate the potential for combining microbial biopesticides with varying control spectrums effectively. Many biopesticides have antimicrobial activity and may therefore interact negatively in combination.ResultsThis study demonstrated that a mixture of Beauveria bassiana and Bacillus subtilis formulations proved potential for simultaneous control of greenhouse whitefly (Trialeurodes vaporariorum Westwood) and tomato powdery mildew (Oidium neolycopersici). Three greenhouse experiments were conducted to assess the efficacy of mixed and single-use treatments. A laboratory experiment comparing the insecticidal effect of each treatment was also conducted. In all greenhouse experiments, the combined treatment controlled the greenhouse whitefly (78.9–88.3%) and tomato powdery mildew (47.2–81.0%) compared to untreated controls, which was as well as each treatment alone. In some greenhouse and laboratory experiments, the mixed treatment showed an approximately 1.32 to 1.78 times higher insecticidal effect compared to single-use treatments. Regarding the control efficacy against the pest and disease, negative effects of microbial agents on each other were not observed.ConclusionsThese results demonstrated the effectiveness of concurrent use of two microbial pesticides examined on dual control of pest and disease and showed potential for improved control of certain pests. The knowledge of this work could suggest the possibility of more environmentally friendly pest control systems with the use of microbial pesticides.

Residue dissipation kinetics, safety evaluation and decontamination of Deltamethrin in tomato and the soil

Tomato powdery mildew, fruit rot, and twig blight are all managed with Deltamethrin. Its residues could still be present in the crops, posing a health risk. The pesticide residue analysis, dissipation rate, and safety assessments were thus examined in green tomatoes. The analytical method for residue analysis was validated according to international standards. Tomato fruits and soil were used to study the dissipation of Deltamethrin 100 EC (11% w/w) at 12.5 g a.i ha−1 for the recommended dose (RD) and 25.0 g a.i ha−1 for the double of the recommended dose (DD). Ethyl acetate was used to extract residues from tomato fruit, and PSA and magnesium sulphate were used for cleanup.The fruits had recoveries ranging from 83% to 93% and the soil sample from 81.67% to 89.6%, with the limit of detection (LOQ) estimated at 0.01 mg kg−1. The matrix effect (ME) was calculated to be less than 20% for the tomato fruits and the soil.Half-lives for RD and DD were 1.95 and 1.84 days, respectively. All sampling days for both doses had dietary exposures of residues below the maximum permissible intake (MPI) of 0.16 mg person−1 day−1. The most effective method of decontaminating tomato residue containing Deltamethrin is blanching.

Entomopathogenic fungus Beauveria bassiana-based bioinsecticide suppresses severity of powdery mildews of vegetables by inducing the plant defense responses.

The entomopathogenic fungus Beauveria bassiana is used commercially as a microbial insecticides against a wide range of agricultural insect pests. Some strains of B. bassiana protect the plants from pathogens, but the underlying mechanisms are largely unknown. Here, we found that prophylactic sprays of commercial bioinsecticide Botanigard on cucumber, tomato, and strawberry plants suppressed the severity of economically damaging powdery mildews. On leaf surfaces, hyphal elongation and spore germination of cucumber powdery mildew, Podosphaera xanthii, were inhibited, but B. bassiana strain GHA, the active ingredient isolated from Botanigard, only inhibited hyphal elongation but had no effect on spore germination of P. xanthii. In addition, strain GHA suppressed powdery mildew symptoms locally, not systemically. Treatment with Botanigard and strain GHA induced a hypersensitive response (HR)-like cell death in epidermal cells of the cucumber leaves in a concentration-dependent manner and inhibited penetration by P. xanthii. Transcriptome analysis and mass spectrometry revealed that GHA induced expression of salicylic acid (SA)-related genes, and treatment with Botanigard and GHA increased the SA level in the cucumber leaves. In NahG-transgenic tomato plants, which do not accumulate SA, the biocontrol effect of tomato powdery mildew by GHA was significantly reduced. These results suggested that B. bassiana GHA induces SA accumulation, leading to the induction of HR-like cell death against powdery mildew and subsequent suppression of fungal penetration. Thus, Botanigard has the potential to control both insect pests and plant diseases.

Reducing Powdery Mildew in High-tunnel Tomato Production in Oregon with Ultra Violet-C Lighting

Widespread outbreaks of tomato powdery mildew (Leveillula taurica and Oidium neolycopersici) are problematic in fresh market tomato (Solanum lycopersicum) crops in western Oregon, USA. In western Oregon, fresh market tomatoes are frequently grown in greenhouses or high tunnels where conditions can promote diseases such as powdery mildew. Heightened concerns about worker safety limit the pesticides available for use in enclosed systems. We studied the efficacy of ultraviolet-C (UV-C) light applications under high-tunnel conditions compared with a standard fungicide program. Plants treated with UV-C had zero incidence of powdery mildew on all sample dates in the first trial. In trial 2, disease incidence was lower on UV-C treated plants than both grower standard and nontreated control early in the study while disease severity remained lower in UV-C than nontreated control and similar to grower standard treatment. Additional research is needed to optimize UV-C treatment intervals to minimize negative effects on plant growth and maximize powdery mildew control.

Overexpression of the C4 protein of tomato yellow leaf curl Sardinia virus increases tomato resistance to powdery mildew.

Powdery mildew (PM) is one of the most important diseases of greenhouse and field-grown tomatoes. Viruses can intervene beneficially on plant performance in coping with biotic and abiotic stresses. Tomato yellow leaf curl Sardinia virus (TYLCSV) has been reported recently to induce tolerance against drought stress in tomato, and its C4 protein acts as the main causal factor of tolerance. However, its role in response to biotic stresses is still unknown. In this study, transgenic tomato plants carrying the TYLCSV C4 protein were exposed to biotic stress following the inoculation with Oidium neolycopersici, the causal agent of tomato PM. Phytopathological, anatomic, molecular, and physiological parameters were evaluated in this plant pathosystem. Heterologous TYLCSV C4 expression increased the tolerance of transgenic tomato plants to PM, not only reducing symptom occurrence, but also counteracting conidia adhesion and secondary hyphae elongation. Pathogenesis-related gene expression and salicylic acid production were found to be higher in tomato transgenic plants able to cope with PM compared to infected wild-type tomato plants. Our study contributes to unraveling the mechanism leading to PM tolerance in TYLCSV C4-expressing tomato plants. In a larger context, the findings of TYLCSV C4 as a novel PM defense inducer could have important implications in deepening the mechanisms regulating the management of this kind of protein to both biotic and abiotic stresses.

Contribution of a WRKY Transcription Factor, ShWRKY81, to Powdery Mildew Resistance in Wild Tomato.

Tomato powdery mildew, caused by Oidium neolycopersici, is a destructive fungal disease that damages almost all of the aerial parts of tomato, causing devastating losses in tomato production worldwide. WRKY transcription factors are key regulators of plant immunity, but the roles of ShWRKYs in wild tomato Solanum habrochaites LA1777 against O. neolycopersici still remain to be uncovered. Here, we show that ShWRKY81 is an important WRKY transcription factor from wild tomato Solanum habrochaites LA1777, contributing to plant resistance against O. neolycopersici. ShWRKY81 was isolated and identified to positively modulate tomato resistance against On-Lz. The transient overexpression of the ShWRKY81-GFP (green fluorescent protein) fusion protein in Nicotiana benthamiana cells revealed that ShWRKY81 was localized in the nucleus. ShWRKY81 responded differentially to abiotic and biotic stimuli, with ShWRKY81 mRNA accumulation in LA1777 seedlings upon On-Lz infection. The virus-induced gene silencing of ShWRKY81 led to host susceptibility to On-Lz in LA1777, and a loss of H2O2 formation and hypersensitive response (HR) induction. Furthermore, the transcripts of ShWRKY81 were induced by salicylic acid (SA), and ShWRKY81-silenced LA1777 seedlings displayed decreased levels of the defense hormone SA and SA-dependent PRs gene expression upon On-Lz infection. Together, these results demonstrate that ShWRKY81 acts as a positive player in tomato powdery mildew resistance.

Powdery Mildew Fungus Oidium lycopersici Infected-Tomato Plants Attracts the Non-Vector Greenhouse Whitefly, Trialeurodes vaporariorum, but Seems Impair Their Development

The mechanism underlying the mediation of the behavior and fitness of non-vector herbivores by fungal pathogen-infected host plants is still unclear. In this study, we experimentally assessed the effects of tomato (Lycopersicon esculentum L.) plant infection status on non-vector herbivores using tomato powdery mildew disease fungus (Oidium lycopersici) and the greenhouse whitefly Trialeurodes vaporariorum as a model multitrophic plant-pathogen, non-vector herbivore interaction. In behavioral bioassays, powdery mildew-infected plants (PM) and plants damaged by combined attack of powdery mildew and whiteflies (PMWF) attracted significantly more whiteflies (32.6% and 58.1% for PM and PMWF, respectively) than control (Con) plants (16.5%) or plants damaged only by whiteflies (WF) (24.2%). Whiteflies feeding on PM or PMWF plants secreted almost twice as much honeydew as on the Con or WF plants. This indicated that whiteflies fed more on diseased plants than healthy plants. However, the preferences and increased feeding did not increase the fitness and immature growth of T. vaporariorum, but significantly prolonged their immature developmental durations, compared with those of whiteflies that developed on Con plants or WF plants. The results showed that powdery mildew infestation attracted more whiteflies but reduced their development and fitness.

基于深度卷积网络的细粒度番茄病害识别

Early diagnosis and accurate identification of fine-grained tomato diseases can control the spread of diseases and insect infections, thus ensuring the healthy development of the tomato industry. In this paper, four lightweight models of Tiny-AlexNet and Mid-AlexNet based on AlexNet and Tiny-VGG16 and Mid-VGG16 based on VGG16 were proposed for 5 kinds of early and late leaf diseases such as tomato powdery mildew. The computation speed of the model is accelerated by reducing the number of neurons in the fully connected layer. In order to avoid degradation in network training, data extension technology is introduced to prevent model overfitting. Among them, the Mid-VGG16 model is significantly better than accurate in early disease recognition, thus verifying the effectiveness of the lightweight model. The proposed model not only improves the accuracy, but also reduces the test time. The results were tested across 20 655 data sets on early and advanced disease. Compared with the traditional model, the average prediction accuracy of the proposed model is improved by about 0.15%, and the detection time is significantly reduced by about 50%. The improved model has strong robustness and high stability. The model can be used to accurately identify early diseases and facilitate real-time detection and prevention of tomato diseases.

Tomato Powdery Mildew Oidium Licopersicum C.M. in a Greenhouse

This article is about spread of tomato powdery mildew (Oidium lycopersicum Cooke et Massee), features, microscopy analysis of pathogen, damage degree. It informs about specific changes and new specialized race in the morphological features of pathogen. It informs about perspective biological and chemical preparations (Qamair, Alrin-B, Kvadris, Strobi, Bayleton, and Topaz) tested in disease control.

Functional Characterization of Tomato ShROP7 in Regulating Resistance against Oidium neolycopersici.

ROPs (Rho-like GTPases from plants) are a unique family of small GTP-binding proteins in plants and play vital roles in numerous cellular processes, including growth and development, abiotic stress signaling, and plant defense. In the case of the latter, the role of ROPs as response regulators to obligate parasitism remains largely enigmatic. Herein, we isolated and identified ShROP7 and show that it plays a critical role in plant immune response to pathogen infection. Real-time quantitative PCR analysis revealed that the expression of ShROP7 was significantly increased during incompatible interactions. To establish its requirement for resistance, we demonstrate that virus-induced gene silencing (VIGS) of ShROP7 resulted in increased susceptibility of tomato to Oidium neolycopersici (On) Lanzhou strain (On-Lz). Downstream resistance signaling through H2O2 and the induction of the hypersensitive response (HR) in ShROP7-silenced plants were significantly reduced after inoculating with On-Lz. Taken together, with the identification of ShROP7-interacting candidates, including ShSOBIR1, we demonstrate that ShROP7 plays a positive regulatory role in tomato powdery mildew resistance.

Simultaneous Detection of Plant- and Fungus-Derived Genes Constitutively Expressed in Single Pseudoidium neolycopersici-Inoculated Type I Trichome Cells of Tomato Leaves via Multiplex RT-PCR and Nested PCR

Type I trichomes of tomato leaves (Solanum lycopersicum Mill. cv. Moneymaker), as outgrowths of the plant epidermis, are suitable for monitoring infection processes of powdery mildew species using a high-fidelity digital microscope (DM) without fungal staining. On the trichomes, tomato powdery mildew (Pseudoidium neolycopersici L. Kiss) isolate KTP-03 produced a maximum of four vigorously elongated hyphae per conidium, which stopped growth approximately 12 days after inoculation. Single trichome cells, invaded by fungal hyphae at various fungal infection stages during the 12-day period after the inoculation of single conidia, were cut at the bases and directly collected with small precision scissors (i.e., microscissors) held by the manipulator under a DM. Subsequently, suc-polymerase chain reaction (PCR) (reverse transcription (RT)-PCR followed by nested (N)-PCR) was conducted to explore gene expression in the infected trichome. We selected intron-containing genes from tomatoes and powdery mildew fungi for the detection of constitutive gene transcripts, namely plasma membrane H+-ATPase (LHA2) and β-tubulin 2 (TUB2) genes. In suc-PCR, a single band from spliced mRNAs of both LHA2 and TUB2 genes were detected, suggesting that both genes were successfully transcribed in single KTP-03-infected trichomes. With combined primers for both LHA2 and TUB2 (multiplex RT-PCR/N-PCR), two bands were detected through the amplification of intron-spliced mRNAs of both genes. Therefore, our single-trichome cell PCR amplification method is effective for detecting the expression patterns of genes from both tomato and powdery mildew fungus. Combinations of digital microscopy, microscissors, and multiplex RT-PCR/N-PCR amplification techniques will be useful for simultaneously analysing the molecular interactions between plants and powdery mildew fungi at the level of single tomato leaf trichome cells. Also, this employed technique will be of benefit in other plant species and crops, possessing leaf trichome cells, to elucidate the molecular interactions between plants and pathogens.

Identification method of vegetable diseases based on transfer learning and attention mechanism

Artificial Intelligence for disease identification is currently the focus of great research interest. Nonetheless, the approach has some problems, for example, identification takes a long time, has low accuracy, and is often limited to a single disease type. Here, we aimed to identify tomato powdery mildew, leaf mold and cucumber downy mildew against simple and complex backgrounds. We developed a vegetable disease identification model, DTL-SE-ResNet50, optimized by SENet and pre-trained by ImageNet to form a new model, SE-ResNet50. The SE-ResNet50 model was trained with the AI Challenger 2018 public database to obtain a new weight. The SE-ResNet50 model with the new weight was then trained by dual transfer learning with a self-built database to create the DTL-SE-ResNet50 model for the identification of vegetable diseases. The model was compared with convolutional neural networks EfficientNet, AlexNet, VGG19, and Inception V3. The experimental results showed that with the same experimental conditions, the identification precision of the new model reached 97.24%, and processing of a single image required 0.13 s. Compared with DTL-CBAM-ResNet50 and DTL-SA-ResNet50, three models has almost the same precision, but time consumption of DTL-SE-ResNet50 was 0.02 s higher than that of DTL-CBAM-ResNet50. Although the time consumption of DTL-SA-ResNet50 was 0.02 s higher than the proposed model, the precision was lower. At the same time, compared with the dual transfer learning model, the model’s precision was 4.1% higher, and the processing of a single image was 0.06 s shorter. Compared with convolutional neural networks, the precision of DTL-SE-ResNet50 was 3.19% higher than the best result, the time consumption of a single image was 0.58 s shorter; Recall and F1 also increased. The method proposed in this paper has high identification precision and short identification time, and it meets the requirements for accurate and rapid identification of vegetable diseases.

First Report of Tomato Powdery Mildew Caused by Leveillula taurica in Taiwan.

Tomato (Solanum lycopersicum L.) is one of the common and important economic crops in Taiwan. In July 2018, tomato leaves with unusual yellowing and lesions were observed in Taichung, Changhua, Nantou, and Yunlin counties in Taiwan. Symptomatic leaves initially showed chlorotic, irregularly shaped patches on adaxial side of leaves; and days later, necrosis appeared in the patches center. The disease incidence was 4 to 25% and occurred mostly on large type tomato in the field and greenhouse while rarely on cherry tomato. Since the pathogen could not be cultured in potato dextrose agar, for initial pathogen observation, symptomatic leaves were examined directly under light microscope. Conidiophores were found emerged through abaxial stomata of the lesion, and were erect, single and sometimes branched, with single-celled and dimorphic conidia, suggesting the lesions were associated with a powdery mildew. The white to hyaline pathogens collecting directly from fresh signs were also examined. Primary conidia were lanceolate, tip point, 50 to 78 × 14 to 22 μm, ratio of 2.3 to 5.9; secondary conidia were cylindrical to clavate, 47 to 72× 14 to 22 μm, ratio of 2.5 to 4.6. Conidial germ tubes were mainly terminal to subterminal and sometimes lateral. Conidial appressoria were alobate to multilobed, and hyphal appressoria were nipple-shaped, lobed to multilobed or even coralloid. No chasmothecia were found in the field samples. One representative specimens of isolates TARI_PM-3 was deposited in the National Museum of Natural Science in Taiwan (accession number F0034683), and DNA extracted from the fresh conidia was amplified respectively with primers PMITS1 and PMITS2 (Cunnington et al. 2003) for the sequences of internal transcribed spacer region (ITS1+5.8S+ITS2, partial sequence). The segment of sequence (accession numbers MT370494 in GeneBank) showed 99.8% identity with the sequence of AB045000, which was identified as Leveillula taurica (Khodaparast et al., 2001). Based on morphology and molecular analysis, the fungus was identified as L. taurica (Braun and Cook 2012; Choi et al. 2019). To confirm the pathogenicity, conidial suspensions (4 × 104 conidia/ml) of L. taurica (isolate TARI_PM-3) were used to inoculate by dropping (10 μl/site) on the abaxial side of leaves of 4-week-old potted tomato (cv. Golden Lucky). The plants were covered with transparent plastic bags for 1 day and then maintained at 16 to 26°C in a greenhouse. Lesion symptoms of leaves similar to those in the field were observed 4 weeks after inoculation, while the controlled plants inoculated with ddH2O showed symptomless. The same fungus was observed on the necrotic patches of the inoculated leaves. In Taiwan, the recorded causing pathogens of tomato powdery mildew are Erysiphe orontii and E. cichoracearum (Tzen et al. 2019). To our knowledge, this is the first report of tomato powdery mildew caused by L. taurica. Typical lesions appeared in the beginning of the disease progress in the field. Through inoculation, the same pathogen could infect sweet peppers (Capsicum annuum L.), which has been also reported as a host of L. taurica (Tzen et al. 2019), suggesting these two crops could be as alternate hosts of L. taurica in the field. Cross-species infection should be taken into consideration while managing the disease.

Evaluation of Natural and Factitious Food Sources for Pronematus ubiquitus on Tomato Plants.

Simple SummaryBiocontrol practitioners have increasingly released generalist predators to control a variety of greenhouse pests. In this study, the effects of alternative food sources on the oviposition rate and the population dynamics of the mite Pronematus ubiquitus were assessed. The alternative food sources were selected among those the mite may encounter or be applied to the tomato crop.Pronematus ubiquitus (McGregor) is a small iolinid mite that is capable of establishing on tomato plants. Once established, this mite has been shown to control both tomato russet mite, Aculops lycopersici (Tryon) (Acari: Eriophyidae), and tomato powdery mildew (Oidium neolycopersici L. Kiss). In the present study, we explored the effects of a number of alternative food sources on the oviposition rate in the laboratory. First, we assessed the reproduction on food sources that P. ubiquitus can encounter on a tomato crop: tomato pollen and powdery mildew, along with tomato leaf and Typha angustifolia L. In a second laboratory experiment, we evaluated the oviposition rate on two prey mites: the astigmatid Carpoglyphus lactis L. (Acari: Carpoglyphidae) and the tarsonemid Tarsonemus fusarii Cooreman (Acari: Tarsonemidae). Powdery mildew and C. lactis did not support reproduction, whereas tomato pollen and T. fusarii did promote egg laying. However, T. angustifolia pollen resulted in a higher oviposition in both experiments. In a greenhouse trial on individual caged tomato plants, we evaluated the impact of pollen supplementation frequency on the establishment of P. ubiquitus. Here, a pollen addition frequency of every other week was required to allow populations of P. ubiquitus to establish.

Dual protection: A tydeoid mite effectively controls both a problem pest and a key pathogen in tomato.

The tomato russet mite (TRM), Aculops lycopersici, and powdery mildew (PM), Oidium neolycopersici, are two major problems in tomato cultivation for which no effective biocontrol solutions exist to date. In a greenhouse compartment, we investigated the potential of preventatively establishing the iolinid omnivorous mite Pronematus ubiquitus on potted tomato plants to control both pest and pathogen simultaneously. Using Typha pollen, P. ubiquitus established well on tomato plants, with numbers reaching up to 250 motiles per tomato leaflet. The built-up population was capable of controlling subsequent infestations with both TRM and PM. This represents the first report of an arthropod protecting a crop against pests as well as disease. The implementation of P. ubiquitus in tomato crops could be a real game-changer as it eliminates the need for repeated pesticide use or sulphur applications. The finding that arthropods can effectively control diseases opens up new opportunities for biological crop protection. © 2021 Society of Chemical Industry.

A machine learning-based spray prediction model for tomato powdery mildew disease

A machine learning-based spray prediction model for tomato powdery mildew disease

CRISPR/Cas9-Mediated Generation of Pathogen-Resistant Tomato against Tomato Yellow Leaf Curl Virus and Powdery Mildew.

Tomato is one of the major vegetable crops consumed worldwide. Tomato yellow leaf curl virus (TYLCV) and fungal Oidium sp. are devastating pathogens causing yellow leaf curl disease and powdery mildew. Such viral and fungal pathogens reduce tomato crop yields and cause substantial economic losses every year. Several commercial tomato varieties include Ty-5 (SlPelo) and Mildew resistance locus o 1 (SlMlo1) locus that carries the susceptibility (S-gene) factors for TYLCV and powdery mildew, respectively. The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) is a valuable genome editing tool to develop disease-resistant crop varieties. In this regard, targeting susceptibility factors encoded by the host plant genome instead of the viral genome is a promising approach to achieve pathogen resistance without the need for stable inheritance of CRISPR components. In this study, the CRISPR/Cas9 system was employed to target the SlPelo and SlMlo1 for trait introgression in elite tomato cultivar BN-86 to confer host-mediated immunity against pathogens. SlPelo-knockout lines were successfully generated, carrying the biallelic indel mutations. The pathogen resistance assays in SlPelo mutant lines confirmed the suppressed accumulation of TYLCV and restricted the spread to non-inoculated plant parts. Generated knockout lines for the SlMlo1 showed complete resistance to powdery mildew fungus. Overall, our results demonstrate the efficiency of the CRISPR/Cas9 system to introduce targeted mutagenesis for the rapid development of pathogen-resistant varieties in tomato.

Statistical analysis of machine learning techniques for predicting powdery mildew disease in tomato plants

Powdery mildew is a dangerous disease that reduces the quality and the yield of tomato fruit rapidly. Its early prediction is a prior requirement for obtaining good quality fruit. Therefore, in this study, the best classifier amongst various classifiers has been discovered using different machine learning algorithms. This classifier can precisely classify whether the meteorological conditions of a particular day are conducive to the development of powdery mildew disease or not. Tomato powdery mildew disease dataset has been tested using various performance measures and the results computed for all the classifiers are promising. Friedman test has been used to rank multiple classifiers and post hoc analysis has also been done using the Nemenyi test. It has been observed in comparison that 62.05% of the total pairs of classifiers perform significantly different from each other, and medium Gaussian support vector machine (MGSVM) is the best classifier with 94.74% accuracy.