Diagrammatic Scale Research Articles

Severity and Reaction to Bacterial Spot of Tomato Hybrids For Industrial Processing

ABSTRACTThe complexity of phytosanitary control for bacterial spot disease is a major challenge in tomato production for industrial processing. The climatic conditions in Goiás and the number of species causing the disease make this management difficult. Thus, this study aimed to evaluate the severity and reaction to bacterial leafspot of sixteen tomato hybrids for industrial processing under the Cerrado conditions in Goiás. The experiment was carried out in randomised blocks, with sixteen tomato hybrids for industrial processing with five replicates, in Hidrolândia‐GO. Once the bacterial spot presence in the area was verified, a severity assessment was performed weekly with a diagrammatic scale, totalling five assessments. The area under the disease progress curve (AUDPC) was calculated. At 115 days after transplanting (DAT), harvesting was performed manually, and vegetative development, yield, number of fruits with Xanthomonas spp. symptoms and scalding by the sun. Bacterial spot symptoms were observed in all hybrids evaluated. Above all, the symptoms observed in the fruits and leaves do not coincide with the hybrid showing the greatest disease severity. The hybrid CVR 6116 had the highest yield, lowest AUDPC and the lowest number of fruits with bacterial‐spot and sunscald damage symptoms.

Melaleuca Essential Oil (Melaleuca alternifolia cheel) in the Control of Beans Diseases

Bean cultivation is vital to the global food and economy, especially in Brazil. Facing challenges from diseases that affect production, it is crucial to seek new strategies to maintain productivity and sustainability. Melaleuca alternifolia, known as the tea tree due to its medicinal properties, has little explored potential in controlling diseases in bean plants. The objective of this work was to evaluate the effectiveness of tea tree essential oil in controlling diseases in bean cultivation. In vitro tests were carried out to evaluate bacterial growth, at concentrations of (0.0%, 0.05%, 0.1%, 0.5%, 1% and 2%). And antibiogram with the bacteria Xanthomonas axonopodis pv. phaseoli, in different concentrations (0.0%, 0.05%, 0.1%, 0.5%, 1%, 2% and 3%). For the fungus Pseudocercospora griseola, sporulation tests were carried out, using direct and indirect methods, at concentrations of (0.0%, 0.05%, 0.1%, 0.5%, 1%, 2%, and 3%). Furthermore, for the fungus Colletotrichum lindemuthianum, mycelial growth tests were carried out with the same concentrations. The experiments took place in vivo, with a completely randomized statistical design, involving five replications per treatment and concentrations varying from (0.0%, 0.05%, 0.1%, 0.5%, 1% and 2%). Disease incidence was assessed using a diagrammatic scale, disease severity, Area under the Disease Progress Curve (AACPD) and Area under the Incidence Progress Curve (AACPI). Melaleuca Essential Oil (EO) inhibited the development of fungi and bacteria in in vitro tests starting at 0.5%. In vivo, Melaleuca Essential Oil (EO) showed a significant reduction in the incidence and severity of the disease from 0.5% in both fungi and bacteria. Melaleuca EO can be an effective alternative for disease control in bean cultivation.

Aerial spraying for downy mildew control in grapevines using a remotely piloted aircraft

Downy mildew is a major problem for grape growers, as this disease is difficult to control. Synthetic fungicides are used to treat downy mildew with handheld backpack and tractor sprayer applications, with high chemical exposure by operators. As important tools for maximising yield, application technologies must be studied to optimise control efficiency. The objective of this study was to evaluate the efficiency of fungicide spray application using Remotely Piloted Aircraft (RPA) for the control of downy mildew in grapevine, with different spray volumes. The study was divided into two experiments using 4 vine lines, 10 blocks and 5 treatments with different mixture volumes: Experiment 1 with RPA application of 5 mixture volumes - 0, 22, 44, 66, and 88 L ha−1; Experiment 2 with RPA application of 3 mixture volumes - 44, 66, and 88 L ha−1 and a backpack application of one mixture volume - 800 L ha−1. Coverage percentage, droplet density and volume median diameter (VMD) were evaluated. Downy mildew severity on grapevine leaves was assessed using visual analysis and a diagrammatic scale. The application of 44 L ha−1 provided the greatest coverage and droplet density in the upper and middle strata; however, the backpack application had a better droplet distribution than the RPA application. Treatments of 44 L ha−1 with RPA and backpack application (800 L ha−1) provided the best disease control. In the trellis system, RPA application must be improved because of the low coverage in the lower parts of the plant, and further studies with different spray nozzles and application heights are needed.

Reação de linhagens de milho à estria bacteriana

Abstract The objective of this work was to select experimental corn lines genetically resistant to the bacterial leaf streak caused by Xanthomonas vasicola pv. vasculorum, in two growing seasons. The treatments were carried out in an experimental randomized block design in the 2019/2020 and 2020/2021 growing seasons, under a covered environment, with open ventilation, with four replicates. Seven lines resistant to and seven susceptible to foliar diseases were evaluated, in addition to two commercial hybrids used as checks. At the corn flowering stage, an artificial inoculation containing 3.78x1010 CFU mL−1 of bacterial suspension was performed, and disease incidence and severity were assessed, based on a diagrammatic scale, every seven days. From these evaluations, the areas under the disease progress curve for each line were calculated, and individual and joint analyses of variance were performed. There is genetic variability among the corn genotypes for reaction to bacterial leaf streak, with a significant effect for the areas under the disease progress curve for incidence (AUDPCI) and severity (AUDPCS) between genotypes and between growing seasons, and for the genotype x season interaction. Lines LV1 and L14 are possible source genotypes for genetic resistance to the bacterial leaf streak.

Diagrammatic scale to quantify the severity of Ascochyta blight in broad bean crops

The objective of this study was to design and validate a diagrammatic severity scale of brown spot on broad bean. We collected 120 leaflets with different level of brown spot damage from commercial crops in the Toluca Valley, which were visually selected based on the expressed symptomology. Sixty leaflets were scanned for evaluation with the software APS PRESS ©Assess 2.0 to determine the real severity value for each leaflet. The damage values allowed us to generate a diagrammatic scale consisting of six different classes: 0(0.0), 1(0.1-6.0), 2(6.1-10.0), 3(10.1-15.0), 4(15.1-40.0), 5(> 40.1-100). The leaflets were visually examined by evaluators who had no prior experience. The results from each evaluator were analyzed with a simple linear regression, obtaining r2 values from 0.0042 to 0.8748, β0 de 0.51 a 9.11, y β1 de 0.132 a 0.925. Using a scale, r2 values were obtained 0.9143 to 0.985, β0 de 0.001 a 0.911 y β1<0.001. The generated diagrammatic severity scale was validated and reproducible, showing high reliability.

Polígono CIE L*a*b* para cuantificar roña (Sphaceloma perseae) en imágenes de frutos de aguacate

Avocado scab causes great economic losses in Mexico and the world. This study aimed to provide an automatic method of quantifying this symptom. The proposed method uses polygonal regions from the a-b plane of the CIE L*a*b* color format to identify a color (even with variations) and different avocado fruit shades. The polygons were used to determine the scab percentage in 70 Hass avocado fruit images. The scab percentage was estimated with a diagrammatic scale, and the regression equation y = 0.5848x, with an r 2 = 0.80, was found when comparing these results with scab percentages obtained from digitized images (observed). With the method presented in this study, the equation y = 0.9923x was found, with an r2 = 0.8672, so the proposed automatic method performed better.

Artificial intelligence tools and a diagrammatic scale for evaluating the quality of coating in treated soybean seeds

Artificial intelligence tools and a diagrammatic scale for evaluating the quality of coating in treated soybean seeds

Diagrammatic scale to evaluate the severity of gray mold (Botrytis cinerea) in pomegranate

The aim of this study was to design and validate a diagrammatic scale to estimate the severity of gray mold induced by Botrytis cinerea in pomegranate cultivation. A total of 120 healthy and diseased fruits with varying degrees of affliction were collected from orchards with active production located in the municipalities of Chilcuahutla and Taxquillo in the state of Hidalgo, Mexico (20° 18’ 11’’ N, 99° 14’ 23’’ W, 20° 32’ 01’’ N, 99° 20’ 03’’ W, respectively). From these, 60 were selected to determine the severity percentage, according to a 6-class scale (Class 0 = 0%, Class 1 = >0% - 5% - 10%, Class 2 = >10% - 25% - 50%, Class 3 = >50% - 75% - 85%, Class 4 = >85% - 90% - 95%, and Class 5 = >95% - 100%), using the 2LOG software. With the obtained data, representative images were selected to build the diagrammatic scale using Adobe Photoshop. The accuracy (r2 ), precision (β0 ), and reproducibility (β1 ) were verified by simple linear regression applied to the data obtained by 12 evaluators with and without experience in the observation of plant diseases. As a result, values of r2 of 0.42 and 0.85 were obtained, without and with the use of the scale, respectively, which confirmed that this tool is suitable to evaluate the severity of the disease accurately and reproducibly.

Diagrammatic scale for the quantification of black spot severity in papaya leaves

Black spot (Asperisporium caricae) is one of the main foliar fungal diseases of papaya crops. This disease acts directly on leaves and fruits causing leaf area reduction and fruit deterioration. The quantification of diseases is a fundamental part of the disease management and control process; therefore, a scale is required to help quantify black spot disease. The objective of this work was to propose a standardized methodology to quantify black spot severity in papaya leaves. A scale was developed considering the maximum and minimum values of the disease in the field that included eight levels of severity: 0.1, 0.3, 0.6, 1.0, 2.3, 5.0, 10.0, and 20.0%. Without the aid of a scale the disease is often overestimated, with absolute errors of approximately 75%. When the scale was used, 100% of the evaluators showed improved accuracy and precision, and absolute error was reduced to the 10% range. The scale also provided good repeatability and high reproducibility. The use of the scale provided an improvement in the R2 values, with mean values of 93 and 92 in the second and third evaluations, respectively, demonstrating that the scale is useful for different aspects of the pathosystem of A. caricae, such as for determining the efficiency of fungicides, characterization of varietal resistance, construction of the disease progression curve, and estimation of damage.

Suitable Methods of Inoculation and Quantification of Fusarium Root Rot in Lentil.

Lentil (Lens culinaris L. subsp. culinaris) is an important grain legume grown worldwide. As its popularity grows among consumers and more acres are produced, new root rot complexes have become more prevalent. This work sought to develop methods for studying root rot caused by Fusarium avenaceum in lentil using controlled environments. The objectives were to (i) find an effective and seed-safe sterilization technique, (ii) optimize the inoculation technique and lentil growing environment, and (iii) develop visual and automated disease scoring systems. Results showed the use of detergent and a low concentration (0.1%) of NaClO (the active ingredient in bleach) maintained germinability and effectively eliminated bacterial and fungal contamination on seeds. Other treatments, such as ethanol, reduced seed germination or failed to kill pathogenic fungi such as Fusarium spp. Placing inoculum at a moderate rate of 1 × 106 spores both directly on the seed and on top of the media covering the seed improved severity scores and reduced escapes compared with placement on top of the media only. Visual severity scoring systems and diagrammatic scales were developed for scoring the cotyledon region and roots. A computer vision algorithm was designed to improve the efficiency of scoring the cotyledon region and roots for disease severity using a simple RGB camera and lightbox. Visual and computer scores were best correlated when images were visually scored on a monitor, and multiple images were averaged. The scores generated from the computer vision algorithm had better correlations with visual scores for cotyledon rot (r = 0.92 and β1 = 0.96) than root rot (r = 0.62 and β1 = 0.67).

Proposed diagrammatic scale to assess heat injury in coffee seedling canopy

A diagrammatic scale with five levels (0, 0.1 – 2.0, 2.0 – 6.0, 6.0 – 10, and 10 – 14) was developed and evaluated to measure the symptoms of heat injury in a coffee seedling canopy. The scale was constructed to increase assessment efficiency and align the estimations more closely with the actual values. Two assessments with the diagrammatic scale and one without were conducted with an interval of seven days. The evaluators using the proposed scale presented estimates with better levels of precision, accuracy, reproducibility, and repeatability than those using a conventional method. The proposed diagrammatic scale was shown to provide a reliable estimate for assessing the symptoms of heat injury on the canopy of in Coffea arabica L. seedlings. Therefore, it is possible to standardize heat injury evaluation methods using this diagrammatic scale, allowing for data comparisons with different cultivars.

Diagrammatic scale for evaluation of Bremia lactucae sporulation in lettuce seedlings

In disease assessment, the use of diagrammatic scales provides a standard reference point for comparison. There is still no precise and accurate scale for the evaluation of sporulation intensity of downy mildew in lettuce seedlings. The objective of this study was to propose a diagrammatic scale for the evaluation of downy mildew severity in lettuce seedlings. Thirty lettuce seedlings with different sporulation intensities were used to develop the proposed diagrammatic scale. Solaris lettuce cultivar was sown, and fifteen days after sowing, inoculations occurred using distilled water, the pathogen sporangia, and Tween 20. The monitoring of disease development was performed daily.When the first sporulation appeared on the cotyledonaryleaves,the proposed scale was verified to meet the minimum and maximum levels of disease severity. Two evaluators verified the accuracy, precision and performed the estimation of the sporulation and reproducibility using a scale. The images obtained are important in the standardization of a scale to identify resistant, tolerant and susceptible plants to downy mildew. Furthermore, it allows validating a diagrammatic scale of sporulation intensity of B. lactucae in lettuce seedlings. Thus, it is the diagrammatic scale developed in the work will guide future research to accelerate the detection of mildew severity in lettuce seedlings.

Severity of Tomato brown rugose fruit virus in tomato (Solanum lycopersicum L.) from a region of Coahuila, México

The purpose of this research was to describe the Tomato brown rugose fruit virus, from three isolates collected in the field and also to use a diagrammatic scale of severity for its evaluation. The isolation was carried out with the collection of 200 ha-1 leaflets, according to a statistical method, from commercial greenhouses. Agdia® immunological strips were used to confirm the symptoms and the virus was identified by RT-PCR. A completely randomized experimental design was established in tomato plants var. Río Grande®, with three treatments or isolates and five repetitions: Blindom F1® tissue, Quiroga® Enza zaiden tissue and Quiroga® Enza zaiden fruit; Controls with phosphate buffer and buffer+celite were used as negative control. The trial began with the inoculation of 45-day-old tomato plants, where only the primary leaves were inoculated. Fertilization was carried out twice a week using macro and microelements from commercial companies. To quantify the percentage of damage to foliage and fruit, a diagrammatic scale of severity was used. The three isolates evaluated differed in the symptoms produced by ToBRFV, where; The Fruto Quiroga® Enza zaiden isolate stood out, with a higher incidence, severity and shorter incubation period compared to the two isolates evaluated.

Comparación de métodos para cuantificar severidad de la roya del cafeto en diferentes tamaños de hojas

Coffee rust is the most important disease of the crop, the severity of leaf damage caused by the pathogen causes leaf abscission and significantly affects the reduction of yields. This investigation was carried out with the objective of comparing the visual method with a digital one, in the quantification of the percentage of severity of the rust in different sizes of leaves. The quantifications of the disease were carried out at the University Clinic for Agricultural Diagnostics at Oriente University. To carry out the experiment, 360 leaves injured with rust were collected from Catuaí Rojo plantations and divided into three groups, categorized according to leaf area into large, medium and small, each group was represented by 120 leaves, initially evaluated by the visual method by two observers with the help of the diagrammatic scale and later with the digital method by analyzing images with the ImageJ® program. The randomized block design was used with a 2x3 factorial arrangement with ten repetitions per experimental unit. The data were processed by analysis of variance. It was found that the severity percentage did not present statistical differences for the digital methodology when the size of the sheets was changed; while, for the visual methodology, therewas an influence of the size of the leaves, observing that the estimated severity increased as the size of the leaves decreased. The digital method is a reliable alternative for the quantification of the severity of attack by coffee rust.

Diagrammatic scale for improved late leaf rust severity assessments in raspberry leaves

Late leaf rust (Thekopsora americana) is a disease that affects raspberry (Rubus idaeus L.), leading to a decrease in raspberry production. The adoption of precise criteria for disease quantification helps decision-making for its management. A diagrammatic scale (DS) is a useful tool for quantifying disease severity in the field. A DS was developed and validated in this study to estimate late leaf rust severity in raspberry leaves. The DS was defined with eight levels of severity (0.2, 0.4, 0.9, 2.2, 5.1, 11.5, 23.9 and 43.2%). The validation was performed by 15 untrained raters in two steps, with and without using the DS. Two approaches were used for statistical analysis: linear regression and Lin’s method. Both analyses demonstrated that the use of the DS improved the precision and accuracy of the disease estimates. The inter-rater reliability was estimated by the coefficient of determination (R2) and the intra-class correlation coefficient (ICC). Again, the use of the DS improved the reproducibility of the estimates. For the first time, a diagrammatic scale was developed and validated to evaluate late leaf rust severity in raspberry leaves.

A Little Helper: Beneficial Bacteria with Growth-Promoting Mechanisms Can Reduce Asian Soybean Rust Severity in a Cell-Free Formulation

Growth-promoting bacteria are already used in sustainable agricultural systems in Brazil. The market is dominated by inoculants and biological pesticides, which do not reach the full potential of this tool in the agricultural sector. This study aimed to evaluate four bacterial strains for the presence of growth promotion mechanisms, as well as the reduction of Asian rust severity in soybean plants and its effects on three antioxidant enzymes during pathogenesis. The plants were treated using the bacterial cells and/or their biosurfactants before inoculation of the pathogen (IOP). Severity was measured based on a diagrammatic scale at 14, 18 and 21 days after IOP, and the activities of the enzymes SOD, CAT, and APX were evaluated 21 days after IOP. Treatments containing only bacterial cells were not efficient in reducing the severity, with losses of leaf area reaching 15%, while the addition of biosurfactants led to a result that is similar to the biofungicide, based on Bacillus subtilis (Serenade®). The presence of direct growth promotion mechanisms can be observed in all isolates, as well as the role of bacterial metabolites, especially lipopeptides, in the biological control of diseases and the modulation of the plant’s immune response.

Activity of Aqueous Extracts from Native Plants of the Yucatan Peninsula against Fungal Pathogens of Tomato In Vitro and from Croton chichenensis against Corynespora cassiicola on Tomato.

Plant extracts are a valuable alternative to control pathogens of horticultural crops. In the present study, four species of pathogenic fungi were isolated from leaf spots on Solanum lycopersicum and identified by traditional and molecular techniques as Alternaria alternata ITC24, Corynespora cassiicola ITC23, Curvularia lunata ITC22, and Fusarium equiseti ITC32. When 11 aqueous extracts from eight native plants of the Yucatan Peninsula were tested against the four fungi in vitro, the extract from Croton chichenensis roots was most active, inhibiting mycelial growth (79-100%), sporulation (100%), and conidial germination (71-100%) at 3% (w/v). A logarithmic-diagrammatic scale of the pathosystem C. cassiicola-S. lycopersicum was established and used to assess disease severity on inoculated tomato plants in a greenhouse after treatment with the aqueous extract from C. chichenensis roots at 12% (w/v). After 21 days, the disease severity was 57% lower than on the control without extract applied. This dose of the extract was not phytotoxic to tomato leaves and was compatible with the beneficial organisms Bacillus subtilis CBCK47 and Trichodema asperellum Ta13-17. The antifungal efficacy of C. chichenensis is highly promising for incorporation into integrated disease management of tomato crops.

Evaluation of the use of alternative control methods of coffee tree diseases in the tropical Amazon

The present study aimed to evaluate the effect of alternative products on the control of coffee brown-eye spot and coffee rust. The experiment was carried out in two conilon coffee plantations, in the following agroforestry system models: a) continuous system (SM-1) and b) mixed system (SC-2). The following treatments were used: i) aqueous plant extract of Himatanthus sucuuba (2%) - SUC, ii) Bordeaux mixture (2%) - CB and iii) control (water). Four monthly samplings of the temporal progress of the diseases were carried out, during the period from October/2019 to January/2020, evaluating the symptoms in three leaves per plant, one from each of the upper, middle and lower thirds of the plant. Incidence percentages were determined according to the number of leaves with symptoms in relation to the total number of leaves sampled. In order to estimate severity, diagrammatic scales were used for each disease evaluated. The obtained data were submitted to routine statistical analysis in R programming with a significance of 5%. Interaction effects were not significant according to the ANOVA test. Significant differences were observed among the treatments studied for the two diseases with the following results: percent reduction of rust incidence: (SUC - 50%, CB - 80% and TEST - 95%) and percent reduction of brown-eye spot: (SUC - 30%, CB - 60 % and TEST - 80%). SUC treatment was more effective in reducing disease severity with the following results: (SUC - 0.26%, CB - 0.40% and TEST - 0.83%) and (SUC - 0.35%, CB - 0.41% and TEST - 0.99%) for rust and brown-eye spot diseases, respectively. The treatment (SUC) proved to be a promising alternative product for the management of brown-eye spot and rust diseases.

Diagrammatic scale for rust severity assessment in broad bean (Vicia faba)

<p><em>Uromyces viciae-fabae</em> has increased in economic importance in broad bean-producing regions of central Mexico. It is therefore convenient to have a standardized system to quantify its severity. The objective of this study was to generate and validate a diagrammatic scale to evaluate the severity of rust on broad bean leaves. We collected infected broad bean leaves with different degrees of damage from commercial crops in the Valle de Toluca and the southeastern region of Mexico State. One hundred and ten leaves representing the disease were taken and group discrimination was carried out to select the ranking visually. Then, the leaves were scanned and evaluated to obtain the real severity value for each leaf using the software ©ASSESS 2.0. A six-class diagrammatic scale was generated: 0 (0.0), 1 (>0.1-6.0), 2 (>6.1-12.0), 3 (>12.1-24.0), 4 (>24.1-56.0) y 5(>56.1-<100), and the exactitude, precision, and reproducibility of its estimations were verified. Fifty-eight leaves were evaluated by 20 evaluators without previous knowledge of the disease; the results obtained were analyzed using simple linear regression. In the initial selection evaluation, average r² values of 0.738 were obtained, without scale, while for the evaluation where the proposed scale was used, the average was 0.93, which confirms adequate levels of accuracy and reproducibility that the proposed scale can provide, for this disease.</p>

Coffee leaf rust assessment: comparison and validation of diagrammatic scales for Coffea arabica

Coffee leaf rust assessment: comparison and validation of diagrammatic scales for Coffea arabica