Disease Severity Percentage Research Articles

Study of the relationship between the severity of downy mildew infection in cucumber and its content of phenols and alkaloids under protected cultivation conditions

The study was carried out to investigate the distribution pattern and intensity of downy mildew disease in three different parts of cucumber plants (upper, middle and lower). Additionally, the study aimed to examine the correlation between the disease severity and the concentration of phenolic and alkaloid compounds in the plants. Under controlled greenhouse conditions, the results demonstrated that the cucumber plants had the most significant disease severity at the middle level, followed by the lower level near the ground. Conversely, no signs of infection were detected at the higher level of the plant. Furthermore, the most severe downy mildew symptoms were noticed in the greenhouses central region, compared to the areas near the front and back entrances. These differences were shown to be statistically significant. Before the onset of downy mildew infection, cucumber plants indicated minimal phenols and alkaloids. From the first day of infection, the concentration of phenols increased and peaked on the twelfth day following infection. Subsequently, it declined on the 15th day. The level of alkaloids peaked on the sixth day of disease infection and then gradually decreased. The cucumber plants exhibited the highest concentrations of phenols and alkaloids around the ground level, followed by the middle and upper levels These variations were statistically significant. The highest correlation coefficient was reported between the disease severity and the cucumbers content of alkaloids and phenols at the middle and the lower level of the two hybrids: Jamila and Mustaqbal. In the Fares hybrid, the highest correlation coefficient between the percentage of disease severity and phenols was 0.905 at the middle level, but it was 0.434 with the alkaloid contents. At the lower level of the plants, the correlation coefficient between disease severity with the alkaloids and phenols was 0.724 and 0.725, respectively.

Evaluating biological agents and plant extracts against Aspergillus niger in pomegranate fruit rot and Ochratoxin A prevention

The aim of the research was to conduct an ecological and biological survey of the extent of pomegranate fruit rot disease and to identify the fungi responsible for these cases in Iraq. The study involved isolating and identifying pathogenic Aspergillus niger isolates capable of producing the mycotoxin Ochratoxin A and evaluating the effects of certain plant extracts, agricultural fungicides, and the yeast S. cerevisiae in protecting pomegranate fruits from A. niger attack during storage. The isolation and identification results revealed that all samples were contaminated with various fungal isolates, with a contamination rate of 100%. The storage experiment results showed that percentage of disease severity, coriander extract significantly reduced the severity to 8.53%, compared to 23.23% for the pathogen-only treatment, with a fungal inhibition rate of 63.28%. This was followed by the treatment with sage extract, which reduced the severity to 10.13% with an inhibition rate of 56.39%. Lastly, the plant-based pesticide Palizin and the biological agent (S. cerevisiae) achieved reductions in disease severity of 11.86% and 10.73%, respectively, with inhibition rates of 45.94% and 53.80% compared to the control treatment. The results showed that treating stored pomegranate fruits with alcoholic coriander extract reduction in the levels of Ochratoxin A, production, with a reduction percentage of 6.92%. The A. niger fungal isolate was able to resist the effect of the plant extract and produce the mycotoxin Ochratoxin A, at a rate of 57.8 microgram/kg, compared to the pathogen-only treatment, which resulted in toxin production of 62.1 microgram/kg.

The Survey of leaf blight disease (Exserohilum turcicum) on maize (Zea mays L.) in Pancur Batu District, Deli Serdang Regency to contribute the food security sustainability

Abstract Leaf blight caused by Exserohilum turcicum is a one of important diseases affecting maize. This leads to yield losses of up to 70% and therefore affect the sustainable food security. The study aim was to determine the distribution of Leaf blight disease caused by the fungus E. turcicum at Sei Glugur Village and Gunung Tinggi Village in Pancur Batu District, Deli Serdang Regency, North Sumatra Province. This research was exploratory research carried out using a survey method, by calculating the incidence and severity of leaf blight disease on maize plants on four fields in two villages, Sei Glugur Village and Gunung Tinggi Village. The highest disease incidence and disease severity were discovered in Sei Glugur Village, field 2, with an average disease incidence percentage of 83.64% and an average disease severity percentage of 33.15%.

In vitro and in vivo Evaluations of the Antifungal Activity of Salicylic Acid and Silicon Against Ganoderma Boninense

Basal stem rot disease (BSR) in oil palms is one of the primary diseases that has led to the wide use of fungicides. This increased the development of fungal isolates resistant to fungicides and led to the search for alternative strategies to replace the use of fungicides. This study aimed to evaluate in vitro antifungal activity of salicylic acid (SA) and silicon (Si) in inhibiting mycelial growth of Ganoderma boninense using Poison Food Technique and to evaluate the in vivo efficacy of Si treatment on oil palm seedlings growth and resistance towards G. boninense. Percentage inhibition of radial mycelial growth (PIRG) was assessed, and Si treatment significantly reduced mycelial radial growth of G. boninenseup to 100% inhibition at concentrations of 200 and 250 mg/L. The half-maximal effective concentration (EC50) for Si was 68.57 mg/L, while for SiO2, it was 273.95 mg/L. The EC50 for salicylic acid was 381.33 mg/L. For in vivo evaluation, oil palm seedlings treated with Si at 150, 200, and 250 mg/L showed the lowest severity of leaf chlorosis and necrotic symptoms, which were 7.36%, 6.49%, and 4.05%, respectively. In contrast, the seedlings without Si showed the highest severity of leaf symptoms. Examination of internal bole tissues of oil palm seedlings treated with Si at a concentration of 250 mg/L also recorded a 3.0% mean percentage of disease severity compared to the untreated infected seedlings, which showed 35.0% disease severity. Our findings demonstrated the potential of Si application in controlling the BSR disease caused by Ganoderma boninense.

Protective role of biosynthesized silver nanoparticles synthesized using sesame oil as biocontrol approach against Erwinia amylovora causing fire blight in pears (Pyrus communis L.)

Erwinia amylovora, the primary cause of fire blight, is thought to be one of the most difficult crop diseases to eradicate. The study aimed to evaluate the performance of essential sesame oil (SO) and silver nanoparticle synthesized by sesame oil SO-AgNPs against E. amylovora. Using GC-MS, it was found that essential sesame oil contains the main component of the oil was sesamin, asarninin, heptane, c-Sitosterol, anethol, and trimethyl -6- ((s) - 4-methylcyclohexan – 3 – en-1-yl)) tetrahydro -2H-pyran. The diluted sesame oil (SO) was used as a reducing agent in synthesis of AgNPs in aqueous solution. By using UV-Visible spectrophotometry (UV–Vis), Dynamic Light Scattering (DLS), High Resolution Transmission Electron Microscopy (HRTEM), and Fourier Transformer InfraRed (FTIR) analysis, the produced Ag NPs were studied. The average particle size of the spherical Ag NPs was determined to be 54.98 nm using data from HRTEM and DLS. SO-Ag NPs (20 µg/ml) showed a promising antibacterial against E. amylovora, producing a 22.9 mm Zone of Inhibition (ZOI) against E. amylovora, followed by SO-Ag NPs (10 ug/ml) that gave 18.2 mm ZOI., compared to gentamicin that produced 13.2 mm ZOI. The most effective inducers were SO-Ag NPs at 10 ug/ml, which decreased the percentage of disease severity by 27.5 and increased the percentage of protection against disease infection by 68.39%. SO-Ag NPs was the most effective inducers which decreased the contents of Malonaldehyde (MDA) and H2O2 by 41.3% and 77.1%. Applying SO-Ag NPs or SO lowered the level of malondialdehyde (MDA) and hydrogen peroxide (H2O2) and improved the fruit set and yield in infected trees. We could assume that, to prevent E. amylovora fire blight disease in pears, SO-Ag NPs, SO are safe, effective, and environmentally friendly alternatives to conventional antibiotics.

Improvement of post-harvest quality of Balady lime fruit with Aloe vera gel and tea tree oil against green mold disease caused by Penicillium digitatum

Penicillium digitatum Sacc is a common postharvest pathogen affecting lime fruits. It causes significant losses in postharvest lime production. An emerging alternative to chemical control is the use of environmentally friendly such as edible and biodegradable films and packaging. The goal of the current study was to test different concentrations of Aloe vera gel (5, 15, 25, 50, 75, and 100% v/v), tea tree oil coating (0.5, 1, 2.5, 5, and 10% v/v), and their combination for controlling P. digitatum in vitro. The results revealed that specific concentrations of Aloe vera gel (75% and 100% v/v), tea tree oil (2.5, 5, and 10% v/v), and Aloe vera gel (25%) + tea tree oil (1%) v/v showed the highest inhibitory effect against the pathogen. The most effective concentrations of Aloe vera gel (75%), tea tree oil (2.5%), and Aloe vera gel (25%) + tea tree oil (1%) were evaluated against the green mold disease of lime under natural infection through storage period (0, 7, 14, 21, and 28 days). Compared to the control group, all edible layers demonstrated a significant delay and reduced in disease severity percentage throughout the storage periods. However, coating lime fruits with a combination of Aloe vera gel (25%) + tea tree oil (1%) successfully prevented the green mold disease of lime fruits over 28 days. The impact of these coatings was evaluated on lime fruit quality maintenance (weight loss, firmness, juice weight, total soluble solids, total acidity, pH, vitamin C, lipid peroxidation content, total phenols, total flavonoid, and total protein) over 28 days of storage during the 2021 and 2022 seasons. All treatments improved fruit quality through the storage period compared with untreated fruits. Treated lime fruits with Aloe vera gel (25%) + tea tree oil (1%) exhibited slight reductions in weight loss and juice weight compared to alternative treatments as an average of the two successive seasons. Simultaneously, this treatment improved fruit firmness, vitamin C levels, total phenols, total flavonoid, and total protein when contrasted with other treatments as an average of the two studied seasons. These findings show that the combination of Aloe vera gel and tea tree oil coatings enhances the shelf life and maintains the quality of lime fruits. They can also be used as an environmentally acceptable, chemical-free alternative treatment to preserve the postharvest quality of lime fruit.

The adult plant resistance (APR) genes Yr18, Yr29 and Yr46 in spring wheat showed significant effect against important yellow rust races under North-West European field conditions

Yellow rust caused by Puccinia striiformis f. sp. tritici (Pst) is one of the most important wheat diseases. Adult plant resistance (APR) genes have gained the attention of breeders and scientists because they show higher durability compared to major race-specific genes. Here, we determined the effect of the APR genes Yr18, Yr29 and Yr46 in North-West European field conditions against three currently important Pst races. We used three pairs of sibling wheat lines developed at CIMMYT, which consisted of a line with the functional resistance gene and a sibling with its non-functional allele. All APR genes showed significant effects against the Pst races Warrior and Warrior (–), and a race of the highly aggressive strain PstS2. The effects of Yr18 and Yr46 were especially substantial in slowing down disease progress. This effect was apparent in both Denmark, where susceptible controls reached 100 percent disease severity, and in United Kingdom where disease pressure was lower. We further validated field results by quantifying fungal biomass in leaf samples and by micro-phenotyping of samples collected during early disease development. Microscopic image analyses using deep learning allowed us to quantify separately the APR effects on leaf colonization and pustule formation. Our results show that the three APR genes can be used in breeding yellow rust resistant varieties of spring wheat to be grown in North-West European conditions, and that deep learning image analysis can be an effective method to quantify effects of APR on colonisation and pustule formation.

Native bacterial bioagents for management of potato soft rot disease caused by Pectobacterium carotovorum subsp. carotovorum

BackgroundThe reduced rate of potato production may occur under different conditions such as field, transit, storage, and marketing. Potato cultivation is frequently affected by various pathogens, among which Pectobacterium carotovorum subsp. carotovorum is a notorious bacterial pathogen responsible for causing bacterial soft rot disease. This pathogen poses a significant threat to potato production worldwide, resulting in substantial economic losses and food security concerns. This study aimed to investigate the effectiveness of three bacterial bioagents, namely Brevundimonas bullata, Bacillus siamensis, and Bacillus velezensis, against P. carotovorum subsp. carotovorum, a notorious bacterium responsible for causing potato tuber soft rot disease.ResultsFifteen isolates were isolated from rhizosphere of potato plants. Out of 15 isolates, 3 isolates, No. 1, 11, and 12, showed highly antagonistic property to control the growth of P. carotovorum subsp. carotovorum in vitro. They were identified as B. bullata, B. velezensis, and B. siamensis, by using 16S rRNA nucleotide sequence analysis. Results from these experiments revealed that three bioagents exhibited notable inhibitory effects on the growth of the pathogenic bacterium. However, B. velezensis stood out as the most effective inhibitor among the tested bioagents, showcasing the highest level of bacteriostatic activity (2.6 cm). The findings from the in vitro experiments provided promising insights into the potential of these bacterial bioagents as natural antagonists against potato tuber soft rot disease. Building upon these promising results, the study recommended the utilization of all tested bioagents for controlling soft rot disease in potato tubers, especially during storage conditions where the risk of bacterial proliferation is heightened. Treatment with B. bullata, B. siamensis, and B. velezensis demonstrates varying degrees of efficacy in controlling the progression of soft rot disease. Notably, B. velezensis shows promising results with relatively low disease severity scores across all time points compared to the other treatments. B. velezensis demonstrates the lowest disease severity percentage at 7.00% compared to the other treatments.ConclusionsThe study underscores the significant potential of B. bullata, B. siamensis, and B. velezensis as effective biological control agents against potato tuber soft rot disease. By targeting the causative agent directly, these bioagents offer a promising avenue for mitigating the detrimental impact of soft rot disease on potato production, thereby contributing to improved crop yield and quality.

EVALUATION OF FLAXSEED OIL AND TRICHODERMA SPECIES AGAINST GREY MOLD DISEASE OF GRAPES

Grapes (Vitis vinifera L.) are included in vital crops in the world with respect to its nutritious and economic value. Botrytis grey mold, also called noble rot, harms grapes and wine quality caused by Botrytis cinerea. Other than chemicals Trichoderma species considered as important bio control agents for management of post-harvest diseases. The current study was designed to evaluate Trichoderma species for their Micoparasitic ability using a modification of a pre-colonized plate method. In-vitro efficacy of flaxseed oil against the Botrytis cinerea of grapes were determined using disc diffusion technique with different oil concentrations 0.2%, 0.6%, and 0.8%. In-vivo efficacy of most effective formulated and non-formulated Trichoderma concentrations was determined by applying on grape bunches against Botrytis cinerea. Trichoderma Harzianum is more effective and showed 67.5% growth inhibition than Trichoderma Viridae having 64% growth inhibition while flaxseed oil with 0.2%, o.6% and 0.8% concentrations showed 30.19%, 33.32% and 34.89% growth inhibition against botrytis cinerea respectively. In water-based Trichoderma concentrations (1×10⁸) showed maximum growth inhibition after 6 days that was 76.46%. However, it was observed that the percent disease severity index of the grape fruits in oil-based formulation showed 16 %, 20 %, and 18% after the 9 days of incubation whereas the water-based Trichoderma formulations showed 20%, 22%, 24% respectively as compared with control. Trichoderma species can be considered as bio-control agent while emulsion oil can be used for better shelf life.

Screening of some commonly cultivated tomato varieties against Fusarium wilt in Jama’are, Bauchi State, Nigeria

Fusarium wilt disease of tomato is caused by Fusarium oxysporum f.sp. lycopersici and is a limiting factor to tomato production in Nigeria. This research was conducted to assess the effect of Fusarium oxysporum on some tomato varieties cultivated in Jama’are, Bauchi state. The objectives of this research work were to isolate and identify pathogen (Fusarium oxysporum) from the soil, to determine the incidence and severity of Fusarium wilt on different varieties of Tomato grown in Jama’are, and to determine the most resistance variety among four different varieties. The experiment was laid in a Completely Randomized design (CRD) with four replications. The four tomato varieties (Roma Savanna, Rio Grande, UC82B and Tropimech) were inoculated at the root region by making shallow groove around the base of the plant in the root region and placing 3 g mycelia plug of 7 days old pure culture of F. oxysporum face-down close to the root of the seedling and covered with soil. At two weeks intervals after treatments the seedlings were then observed for symptoms of wilt infection. Data on disease incidence (%), were collected based on observation after which they were analyzed using Analysis of Variance (ANOVA) test. The Disease Incidence Percentage for Roma Savanna, Rio Grande, UC28B and Tropimech were evaluated to be 51.6%, 18.2 %,38.4 % and 43.3 % respectively while the Disease Severity Percentage were 72.1%, 24.8%, 40.9% and 62.3% respectively. The findings of this research reveals that; there is a significant effect of F. oxysporum on the tomato varieties, all the varieties were severely infected to some degree, and that of all species, Roma savanna was moderately resistant to F. oxysporum to some degree. This agrees with other findings in the literature, as Fusarium oxysporum affects different varieties of tomato at different growth stages. Also, it was observed that screening excises involving selecting of non-infected seedlings with Fusarium species and other fungi should be done prior to transplanting.

Effect of Environmental Factors in the Development of Powdery Mildew in Okra [Abelmoschus esculentus (L.) Moench

In order to study the effect of environmental factors in the development of powdery mildew in okra [Abelmoschus esculentus (L.) Moench] an experiment was carried out at the College of Agriculture, IGKV, Raipur, Chhattisgarh during kharif (2019-20). The correlation analysis revealed that the age of the crop was significantly, positively correlated and T max, T min and morning RH were significantly, negatively correlated with the disease severity. In addition to this by linear regression analysis, it was observed that plant age (69%), maximum temperature (62%), minimum temperature (60%) and morning relative humidity (46%) contributed in percent disease severity. Based on the proportional measures of extent of infection at different times the apparent rate of infection was found maximum during 70-84 DAS. At this time when the disease progress the average maximum temperature was 29.3℃, minimum temperature 14.9℃, morning relative humidity 87.6% and evening relative humidity 38.33%.

Uji Efektivitas Daun Sirih Dalam Menghambat Pertumbuhan Layu Bakteri Ralstonia solanacearum Pada Tanaman Terung

Ralstonia solanacearum is one of the important diseases in eggplant plants which causes bacterial wilt in plants so control efforts need to be taken. One alternative control method is using vegetable pesticides from betel leaf powder. This research aims to determine the effectiveness of betel leaves in inhibiting the growth of R. solanacearum bacterial wilt on eggplant plants. This research used a Completely Randomized Design (CRD) with 5 treatments and 5 replications, each replication using 4 plants so there were 100 experimental units. The treatment used doses of 25 gr, 50 gr, 75 gr, 100 gr of betel leaf powder, and as a comparison, namely the control treatment in this study. Observations were made every day after inoculation to see the incubation period that occurred in the eggplant plants and once a week to observe the disease intensity and severity of the disease in the eggplant plants. The results of this study showed that an effective treatment with a dose of 100 g of betel leaf powder with an eggplant plant age of 47 days after showed the lowest treatment in suppressing Ralstonia solanacearum bacteria, namely a disease intensity percentage of 15% with a disease severity percentage of 20% and had the lowest incubation period. slow, namely 19 days, this shows that betel leaves have an effect in suppressing disease attacks caused by R. solanacearum on eggplant plants because they have antibacterial active compounds.

Standard Area Diagrams for Pecan Leaf Scab: Effect of Rater Experience, Location, and Leaf Size on Reliability and Accuracy of Visual Estimates.

Assessments of the severity of scab (Venturia effusa), an economically significant disease of pecan, are critical for determining pecan cultivar susceptibility, disease epidemiology, and integrated disease management approaches. We developed a standard area diagram (SAD) set to aid in assessments of pecan leaflet scab. Leaflets with scab lesions were harvested and scanned using a flatbed scanner at 600 dpi, and Fiji (ImageJ) was used to determine the actual percent disease severity. The SADs had 10 leaflets ranging in severity from 0.2 to 48.9%. Forty "small" (1.34 to 7.43 cm2) and 40 "large" (7.67 to 25.9 cm2) leaflet images were randomized for rater assessments. The images were assessed twice by 36 raters, first without and then with the SADs as a guide. Data were subjected to analysis using Lin's concordance correlation coefficient (LCC, pc) to determine the accuracy of ratings and by intraclass correlation coefficient (ICC) analysis to determine interrater reliability. The effects of rater experience, rater location, and leaflet size were also determined. The SADs significantly improved the agreement between raters and the actual values (LCC, pc = 0.70 and 0.84 without and with the SADs, respectively). The reliability of estimates was improved (ICC = 0.54 and 0.82 without and with the SADs, respectively). The effect of rater location on overall concordance was significant without and with the SADs based on an analysis of variance using a generalized linear model and lsmeans separation (P < 0.05). A generalized linear mixed model analysis revealed that there was a significant interaction between rater location, experience, and the use of the SADs, with some raters having greater improvement in generalized bias and concordance. Raters had a significantly better accuracy when rating "small" leaves (LCC, pc = 0.86) compared with "large" leaves (LCC, pc = 0.82) when using the SADs, highlighting the impact of psychophysics on field evaluations of plant disease severity. The proposed SADs will serve as an improved tool for performing pecan leaflet scab assessments by the pecan research community.

Integrated Control of Some Fungal Diseases Affecting Guava and Pomegranate from Farm to Fork in Egypt

These studies aim to identify a group of pathogens and design an integrated control program reducing the infection in Guava Psidium guajava and Pomegranate Punica granatum by cross inoculation method. Almost eight fungi were collected from governorate Ismaelia and Behera in 2019. Alternaria alternate, Fusarium spp, Phomopsis psidii, Macrophomina spp., Cercospora spp. Botrytis cineria and Pestalotia spp. were the most frequencies isolated fungi on all fruits. In the second season 2020 we treated trees with biocides, fungicides and fertilizer they gave significant differences between the treated treatments and control .The bluegreen algae bio treatment, showed the best results compared with both of RizoN and Plantagaurd treatments, the percentage of disease severity on the leaves was 13.4%, compared to the control45%, the best chemical treatment was Fungalpro, Topsin and Collise, where the disease severity was 0% in case of guava ,the same results obtained in pomegranate .At the end of the season, the best results were in the treatment with fungalpro which gave the least disease severity percentage on each of the leaves, branches and fruits in both guava and pomegranate .In the third season 2022 we applied integrated control program there were a significant decrease in pathogenic fungi in leaves, branches, flowers and ripe fruits, as the population at the end of the season for some fungi reached zero, such as Phomopsis sp. and Pestalotia sp. As Alternaria fungus, the results showed significant differences compared with the control, with regard to Guava, the percentage of disease severity in fruits was 8.75% and 9.75% in both Ismailia and South of Tahrir, respectively, compared to the control, which reached 85.5% and 88.5% in Ismailia and South of Tahrir, respectively. The results for pomegranate followed the same pattern.

Phyto-extracts Mediated Biological Control of Citrus Canker

Citrus is second most important fruit crop and has significance economic importance in Pakistan. In Pakistan 2.17 million tonnes citrus was produced on area of 1.94 million acre. Citrus is mostly cultivated in Punjab and affected by different types of plant pathogens. Citrus canker is the most harmful disease among the major diseases of citrus which is caused by Xanthomonas axonopodis pv. citri. The copper based fungicides are mostly employed to manage the citrus canker in the field but excessive use of chemicals have negatively impacted the environment and warrant the need to find out organic solutions therefore the current study was aimed at identifying suitable plants extracts for the control of citrus canker bacterium. Isolation of the bacterium X.axonopodis was done through streaking on agar plate technique. Morphological and bio-chemical tests such as gram staining, KoH test, catalase test and starch hydrolysis test were performed to examine the bacteria X.axonopodispv. citri. Plant extracts were evaluated, in vitro, against the X.axonopodis pv. citri through paper disc method which showed the inhibition zone against the disease. The 100 percent extract of garlic, ginger, aloevera, moringa were used used along with the streptomycin as a positive control. The inhibition zone was 11.67mm and 10.83mm due to garlic and moringa extracts respectively while it was 16.67mm in case of positive control. The ginger and aloevera extracts proved ineffective against the citrus canker bacterium.The efficacy of garlic and moringa extracts were also checked against the X. axonopodis pv. citri under glasshouse conditions. The inoculum was sprayed on Kinnow plants, with three replicates, for each extract and data was recorded 15, 20, 25, 30 and 35 days post inoculation (dpi).The recorded disease severity percentage, after 35dpi, on garlic and moringa treated plants were 9.67% and 14.27% respectively while the 27% disease severity was recorded on control (plants sprayed with autoclaved distilled water). The garlic extract proved to be most effective followed by moringa extract which could be used as a potential organic solution to control citrus canker.

Evaluation of wheat genotypes for resistance to bacterial leaf streak caused by Xanthomonas translucens pv. undulosa in field and greenhouse trials

Bacterial leaf streak (BLS), caused by Xanthomonas translucens pv. undulosa, is a devastating cereal disease that is becoming more common in Iran. A cost-effective and realistic strategy to cope with BLS is planting of BLS-resistant cultivars. To discover BLS-resistant genotypes, 360 hexaploid wheat genotypes were selected and inoculated with a local strain of Xanthomonas translucens pv. undulosa in the field and greenhouse in two years (2019 & 2020). In the field experiments, disease reaction of wheat plants was assessed based on both percentage of disease incidence (PDI) and the percentage of disease severity (PDS). In the greenhouse experiment, disease reaction was evaluated as the disease severity (DS). The genotypes with PDS, PDI, and DS values ≤ 20% were considered BLS-resistant or semi-resistant. Genotypes with zero or very low PDS, PDI and DS during the first and second years were considered highly resistant to the disease. Despite resistant genotypes being more prevalent than susceptible genotypes in each year, genotype responses to BLS varied over the two years, but in both years, most genotypes showed a resistance response. Forty-six genotypes (12.8%) were consistently BLS-resistant across years in the field and greenhouse trials. In 2020, field BLS intensity ratings (PDI and PDS) were positively correlated with flag leaf width and days to maturity. In contrast, PDI and PDS were negatively correlated with plant height, peduncle length, and spike length. In 2019, no significant correlations were found between PDI, PDS, and phenotypic traits. Cluster heatmaps and principal component analysis (PCA) separated resistant and susceptible genotypes. In BLS-resistant genotypes, plant height, peduncle length, and spike length were significantly longer, but flag leaf width and days to maturity were shorter. This study identified new and diverse sources of resistance to BLS that could be used in wheat breeding efforts.

Use of Biological and Chemical Compounds for the Integrated Management of Apricot Powdery Mildew in Egypt

This study aims to evaluate an integrated management program for powdery mildew caused by Sphaerotheca pannosa in apricot trees Prunus armeniaca, where four fungicides Copper, Carbendazim, Praiz and Topas) and three biocides ( Bio Z , Bio Arc and Activator Yeasts ) were evaluated in the first season 2020 in Ismailia and Beheira governorates in the regions of South Tahrir and Nubariya. All compounds significantly reduced the percentage of disease severity on leaves and flowers compared to the control, and the activator yeasts was among the best treatments, as it recorded in the last spraying a percentage of disease severity on leaves and flower 28.5% and 27.6% respectively compared with control 52.7 %and 56.2%, followed by the biocides Bio Z and Bio Arc.In the second season 2021, the compounds were evaluated during the flowering period, which led to their precipitation and the occurrence of plant toxicity for flowers at their highest rates with copper. As for the biocides compounds, they were completely safe.From here, an integrated control program was designed for two seasons 2022 and 2023 that combines fungicides and biocides. It is applied early before flowering. It gave excellent results, reduced the rate of fungicide use, and was safer and cost-saving.

Antagonistic potential of rhizobacterial isolates against fungal pathogens causing rhizome rot in turmeric.

The study aims to select potent bacterial antagonists to be used as biocontrol agents against rhizome rot disease in turmeric (Curcuma longa L.). A total of 48 bacterial isolates were isolated from the rhizosphere of turmeric. These isolates were screened for their in vitro antagonism against Fusarium solani FS-01 and Pythium aphanidermatum (ITCC 7908). Production of volatile organic compounds and chitinase activity were also performed. Among the tested isolates, two bacterial isolates (IJ2 and IJ10) showed the highest inhibitory activity against these fungal pathogens. GC/MS analysis of the crude extract produced by Pseudomonas sp. IJ2 and B. subtilis IJ10 was found to contain many bioactive compounds with antifungal and antimicrobial activities. The rhizome treatment with these isolates exhibited the lowest percent disease severity with high biocontrol efficacy against the tested pathogens. These isolates with promising antagonistic potential, therefore, can be used as biocontrol agents against rhizome rot in turmeric.

Efficacy of stingless bee (Heterotrigona itama) propolis aqueous extract in controlling anthracnose and maintaining postharvest quality of chilli (Capsicum annuum) during storage

Anthracnose, mainly caused by Colletotrichum spp., is one of the fungal diseases resulting in major economic losses affecting chilli production worldwide. Propolis extract from honeybee has been discovered for its antifungal properties, which can potentially reduce postharvest decay. Therefore, the present work investigated the efficiency of aqueous extract of stingless bee (Heterotrigona itama) propolis in controlling postharvest anthracnose and maintaining quality of chilli. Colletotrichum capsici was isolated and characterised from infected chilli. Stingless bee propolis extract at different concentrations of 1, 2, 5, and 10% were assessed in vitro to inhibit the mycelial growth of C. capsici. The best concentration in inhibiting C. capsici growth was thereafter selected for in vivo experiments. All tested concentrations of stingless bee propolis extract inhibited the mycelial growth of C. capsici the highest being 35% inhibition from the treatment of 10% propolis extract. The extract at this concentration was therefore tested in vivo, and showed effectiveness in reducing the percentage of disease severity in chilli. The propolis extract was also efficient in reducing weight loss, retaining firmness, pH, total soluble solid, and colour (a* value) throughout 21-day storage at 10°C. The present work demonstrated that aqueous extract of stingless bee propolis could have the potential to control anthracnose disease and delay deterioration, thus maintaining the postharvest quality parameters of chilli. This natural product from stingless bee has the prospect to be an alternative to synthetic fungicide.

Exploring the nano-fungicidal efficacy of green synthesized magnesium oxide nanoparticles (MgO NPs) on the development, physiology, and infection of carrot (Daucus carota L.) with Alternaria leaf blight (ALB): Molecular docking

In this research, green synthesized magnesium oxide nanoparticles (MgO NPs) from lemon fruit extracts and their fungicidal potential was evaluated against Alternaria dauci infection on carrot (Daucus carota L.) under greenhouse conditions. The scanning and transmission electron microscopy (SEM and TEM) and ultra-violet (UV) visible spectroscopy were used to validate and characterize MgO NPs. The crystalline nature of MgONPs was determined using selected area electron diffraction (SAED). MgO NPs triggered substantial antifungal activity against A. dauci when exposed to 50 and 100 mg L−1 concentrations but the higher antifungal potential was noticed in 100 mg L−1 under in-vitro conditions. In fungal inoculated plants, a marked decrease in growth, photosynthetic pigments, and an increase in phenol, proline contents, and defense-related enzymes of carrot were seen over control (distilled water). However, foliar application of MgO NPs at 50 and 100 mg L−1 resulted in significant improvement of plant growth, photosynthetic pigments, phenol and proline contents, and defense enzymes activity of carrots with and without A. dauci infection. Spraying of MgO NPs at 100 mg L−1 had more plant length (17.11%), shoot dry weight (34.38%), plant fresh weight (20.46%), and root dry weight (49.09%) in carrots when challenged with A. dauci over inoculated control. The leaf blight indices and percent disease severity were also reduced in A. dauci inoculated plants when sprayed with MgO NPs. The non-bonding interactions of Alternaria genus protein with nanoparticles were studied using molecular docking.