Search Results (97)

Tree diseases affecting Camellia japonica have emerged as a significant threat to the health and longevity of this ornamental tree, particularly in countries where this tree species is widely distributed and cultivated. Among these, Pestalotiopsis spp. have been frequently reported and are considered one of the most impactful fungal pathogens, causing leaf blight or leaf spot, in multiple countries. Understanding the etiology and distribution of these diseases is essential for effective management and conservation of C. japonica populations. The traditional methods based on pathogen isolation and pure culture cultivation for diagnosis of tree diseases are labor intensive and time-consuming. In addition, the frequent coexistence of the major pathogens with other endophytes within a single C. japonica tree, coupled with inconsistent symptom expression and the occurrence of pathogens in asymptomatic hosts, further complicates disease diagnosis. These challenges highlight the urgent need to develop more rapid, accurate, and efficient diagnostic or monitoring tools to improve disease monitoring and management on trees, including C. japonica. To address these challenges, we applied a metagenomic approach to screen fungal communities within C. japonica trees. This method enabled comprehensive detection and characterization of fungal taxa present in symptomatic and asymptomatic tissues. By analyzing the correlation between fungal dominance and symptom expression, we identified key pathogenic taxa associated with disease manifestation. To validate the metagenomic approach, we employed a combined strategy integrating metagenomic screening and traditional fungal isolation to monitor foliar diseases in C. japonica. The correlation between dominant taxa and symptom expression was confirmed. Simultaneously, traditional isolation enabled the identification of a novel species, Pestalotiopsis, as the causal agent of leaf spot disease on C. japonica. In addition to confirming previously known pathogens, our study led to the discovery and preliminary characterization of a novel fungal taxon with pathogenic potential. Our findings provide critical insights into the fungal community of C. japonica and lay the groundwork for developing improved, rapid diagnostic tools for effective disease monitoring and management of tree diseases. Full article

Soilborne diseases cause losses of 45–70% in faba bean in Ethiopia. Studies were undertaken to define soilborne pathogens and their complexes in Ethiopia. First, the severity of root rot was assessed in 150 field sites across seven Ethiopian regions. Soil samples were collected, and the DNA of 29 pests and pathogens was quantified using a commercial quantitative PCR (qPCR) soil testing service. There was a very high incidence rate of Macrophomina phaseolina, as well as Pythium clades F and I. The other detected species in order of incidence included Fusarium redolens, Rhizoctonia solani, Aphanomyces euteiches, Phytophthora megasperma, Sclerotinia sclerotiorum and S. minor, and Verticillium dahliae, as well as low levels of Thielaviopsis basicola. Five anastomosis groups (AG) of R. solani, namely AG2.1, AG2.2, AG3, AG4, and AG5, were detected, of which AG2.2 and AG4 were most prevalent. We believe this is the first report of occurrence for Ethiopia of A. euteiches, Ph. megasperma, T. basicola, and the five AGs for R. solani. There were very high incidence rates of the foliar pathogens Botrytis cinerea, B. fabae, Didymella pinodes, and Phoma pinodella and of the nematode Pratylenchus thornei, followed by P. neglectus and P. penetrans. The root rot severity and distribution varied significantly across regions, as well as with soil types, soil pH, and soil drainage. Subsequently, metabarcoding of the soil DNA was undertaken using three primer pairs targeting fungi (ITS2), Fusarium species (TEF1 α), and Oomycetes (ITS1Oo). The ITS2 and TEF1α primers emphasized F. oxysporum as the most abundant soilborne fungal pathogen and highlighted F. ananatum, F. brachygibbosum, F. brevicaudatum, F. clavum, F. flagelliforme, F. keratoplasticum, F. napiforme, F. nelsonii, F. neocosmosporiellum, F. torulosum, and F. vanettenii as first reports of occurrence for Ethiopia. The ITS1Oo primer confirmed Pythium spp. as the most prevalent of all Oomycetes. Full article

To address the need for improved nutritional value of organically grown wheat, this study investigated the impact of silicon treatments (AdeSil, ZumSil) on yield, health status, and bioactive compound content in spring wheat cultivars. The 2019–2020 research evaluated different application variants: seed dressing, foliar sprays, and their combinations. Comprehensive seed dressing combined with two foliar treatments, (variant B) and two foliar treatments (variant C), significantly increased yield (by an average of 8.9% and 7.6% vs. control, respectively). These variants beneficially affected fungal disease resistance mainly in the stressful 2019; in optimal 2020, they showed no clear advantage over the control, which performed similarly or better. Seed dressing (variant D) increased total phenolic acids (PAs) content and antioxidant activity, with the spelt cv. Wirtas exhibiting the highest levels. Silicon treatments modified alkylresorcinols (ARs) content, but effects depended on the year, cultivar, and application variant, not always exceeding the control. Silicon treatments, especially when applied in combination (seed dressing and foliar application), can improve spring wheat yield and favorably modify PAs content, enhancing grain nutritional value. However, the plant response regarding health status and ARs content is strongly conditioned by cultivar specificity and the prevailing environmental conditions of the growing year. Full article

Salvia miltiorrhiza is a traditional herbal remedy for cardiovascular diseases and is in high demand in the market. Excessive chemical fertilizer application, resulting from unscientific fertilization practices, reduced the tanshinone content in S. miltiorrhiza roots. This study investigated how different fertilization types alter the endophytic microbial community composition of S. miltiorrhiza through field experiments, aiming to understand how fertilization affects its medicinal quality. The results showed that root fertilizers (F1) significantly increased root biomass and tanshinone I content, whereas foliar fertilizers (F2) increased tanshinone IIA content. High-throughput sequencing further revealed that F2 treatment significantly decreased the Shannon index of endophytic bacteria while significantly increasing the Shannon index of endophytic fungi. Co-occurrence network analysis revealed that fertilization significantly altered fungal community complexity and modularity, with F1 increasing network nodes and edges. Variance partitioning analysis indicated fungal diversity more strongly influenced medicinal compound levels under F2 and a combination of both (F3) than bacterial diversity. Septoria and Gibberella were positively correlated with tanshinone I and cryptotanshinone content under F2 treatment, respectively. Notably, the unique strains were isolated from different fertilization treatments for subsequent bacterial fertilizer development. These findings elucidate microbial responses to fertilization, guiding optimized cultivation for improved S. miltiorrhiza quality. Full article

Anthracnose in beans is an important disease caused by Colletotrichum lindemuthianum, which affects crop productivity and infects the plant in all growth stages, affecting the quality of the pod and grains. The most viable strategy to control this disease is using bean cultivars; however, fungal variability is a limitation. Among the strategies proposed is using phosphite-based compounds, which can act as fungicides or priming stimulators. This study aimed to evaluate the antifungal activity of a phosphite-based solution (potassium phosphite (H₃PO₃), potassium hydroxide, and potassium citrate, in a formulation of phosphorus (P₂O₅) 28% and potassium (K₂O) 26%) on C. lindemuthianum under in vitro conditions. In addition, its effects as a defense inducer in Sutagao bean plants was determined by changes in disease severity and the expression of PR1, PR3, PR4, and POD (defense-related genes) in plants treated with the phosphite solution before infection with the fungus. The results showed that the potassium phosphite solution had a statistically significant antifungal effect on C. lindemuthianum, reducing mycelial growth by 42% and germination by 48%, at a dose of 5 mL L⁻¹. Foliar application of the phosphite-based solution showed a 17% reduction in anthracnose severity associated with high expression of the PR1, PR3, PR4, and POD defense genes, which increased in plants that were subsequently infected with the pathogen, demonstrating a priming effect. In conclusion, a potassium phosphite solution can be included in a management program to control bean anthracnose. Full article

The low efficacy of traditional single-component pesticide formulations has resulted in excessive pesticide application, the evolution of pest resistance, and a range of food safety and environmental concerns. Developing efficient composite nanopesticides represents a critical strategy for addressing the above challenges. In this study, solid nanodispersions (SNDs) co-loaded with prochloraz and azoxystrobin were constructed through a self-emulsifying carrier adsorption method. The antifungal activities of the composite SND with a 14:1 ratio of prochloraz to azoxystrobin against Fusarium graminearum and Pyricularia oryzae were 2.3-fold and 1.6-fold higher than those of commercial microemulsions (MEs) with the same proportion of active ingredients. The SND could cause severe oxidative damage to fungi, by reducing the activities of superoxide dismutase (SOD) and catalase (CAT), and break the permeability of cell membranes, resulting in fungal death. Additionally, the composite SND exhibited superior foliar wettability and biosafety with a minimal environmental cost, thereby enhancing the pesticide’s effective utilization rate. This research provides theoretical and technical support for the design and development of high-efficiency composite nano-fungicide, holding promise for sustainable disease management. Full article

Palm trees (Arecaceae) are among the most popular ornamental plants worldwide. Despite extensive research on the fungi associated with Arecaceae, the diversity and ecological dynamics of fungi affecting ornamental palms remain poorly studied, although they have significant impact on palm health and economic value. Furthermore, while research on palm fungal diversity has traditionally focused on tropical assemblages, ornamental palms in temperate climates offer a unique opportunity to explore the diversity of palm fungi in non-native habitats. The present study conducted a preliminary assessment of the diversity and ecology of potential phytopathogenic fungi associated with foliar lesions on various ornamental palm host species in Portugal, combining morphological examination, PCR-based genomic fingerprinting, and biodiversity data analysis. The examination of 134 foliar lesions sampled from 100 palm trees resulted in a collection of 2064 palm leaf spotting fungi (PLSF), representing a diverse fungal assemblage of 320 molecular operational taxonomic units (MOTUs) across 97 genera. The overall fungal community composition revealed a distinct assemblage dominated by Neosetophoma, Alternaria, Phoma, and Cladosporium, with a profusion of infrequent and rare taxa consistent with a logseries distribution. Significantly positive co-occurrence (CO) patterns among prevalent and uncommon taxa suggest potential synergistic interactions enhancing fungal colonisation, persistence, and pathogenicity. The taxonomic structures of the PLSF contrasted markedly from tropical palm fungi, especially in the prevalence of pleosporalean coelomycetes of the Didymellaceae and Phaeosphaeriaceae, including recently introduced or not previously documented genera on Arecaceae. This novel assemblage suggests that climatic constraints shape the structure of palm fungal communities, resulting in distinctive temperate and tropical assemblages. In addition, the fungal assemblages varied significantly across palm host species, with temperate-native palms hosting more diverse, coelomycete-enriched communities. The present findings highlight foliar lesions as hyperdiverse microhabitats harbouring fungal communities with intricate interactions and a complex interplay of climatic, host, and ecological factors. With climate change altering environmental conditions, the identification of fungi thriving in or inhabiting these microhabitats becomes crucial for predicting shifts in pathogen dynamics and mitigating future fungal disease outbreaks. Understanding these complex ecological dynamics is essential for identifying potential phytopathogenic threats and developing effective management strategies for the health and sustainability of ornamental plants. Full article

The present study aimed to evaluate the effect of silver nanoparticles (AgNPs) on the development of Colletotrichum lindemuthianum, the progression of anthracnose symptoms, and the growth of common bean plants. For this purpose, the fungal mycelial growth and conidial germination were assessed at AgNP concentrations of 0, 10, 30, and 50 mg·L⁻¹ after seven days of incubation, as well as at 0, 0.1, 0.5, 1, 10, 30, and 50 mg·L⁻¹ after 72 h, respectively. Bean plants of the IPR Uirapuru cultivar were sprayed at the V3 growth stage with AgNPs at 0, 10, 30, or 50 mg·L⁻¹, either two days before, on the day of, or two days after inoculation. Conidial germination and appressoria melanization were measured on the leaf discs collected 24, 48, and 72 h after inoculation, and disease severity was assessed at 7 and 12 days post-inoculation. Another set of bean plants grown under the same conditions was used to evaluate growth promotion by AgNPs. For this, the plants were sprayed twice (with a seven-day interval), starting at the V3 growth stage, with AgNPs at 0, 10, 30, or 50 mg·L⁻¹. Seven days after the second treatment, plant length and the fresh and dry weights of shoots and roots were measured, and the foliar pigments were quantified. The AgNPs did not reduce mycelial growth but completely inhibited the germination of C. lindemuthianum conidia. The severity of anthracnose decreased with the AgNPs in a dose- and application time-dependent manner, with the highest reduction (90%) observed when applied on the same day as an inoculation at 50 mg·L⁻¹. This was strongly linked to a 70% decline in conidia germination and appressorium melanization on bean leaves. AgNPs at 50 mg·L⁻¹ promoted plant growth by increasing the total length by 3%, as well as the fresh weights of bean shoots and roots by 17% and 90%, respectively, but did not affect the content of leaf pigments. Full article

Studies were initiated to find new effective fungicides to use under field conditions to discover novel approaches for optimizing disease management in sugar beet crops. Cercospora leaf spot (CLS), a prevalent foliar disease in sugar beet crops worldwide, is caused by the fungal pathogen Cercospora beticola Sacc. This disease has become the most prevalent pathogen in sugar beet crops across nearly all European growing regions, including Hungary. The epidemic spread of this disease can cause up to 50% yield loss. The use of fungicides has been a cornerstone in managing CLS of sugar beet due to the limited efficacy of non-chemical alternatives. However, the emergence of fungicide-resistant strains of Cercospora beticola Sacc. in recent decades has compromised the effectiveness of certain fungicides, particularly those belonging to the QoI (FRAC Group 11) and DMI (FRAC Group 3) classes. Hungary is among the many countries where resistance to these fungicides has developed due to their frequent application. Picolinamides represent a novel class of fungal respiration inhibitors targeting Complex III within the Quinoine-Inside Inhibitor (QiI) group. Two innovative fungicides from this class, fenpicoxamid and florylpicoxamid (both classified under FRAC Group 21), were evaluated for their efficacy in managing CLS of sugar beet in Hungary during the 2020 and 2021 growing seasons. Both fungicides were applied as formulated products at various application rates and demonstrated superior efficacy in controlling CLS compared to untreated control plots and the reference fungicides difenoconazole and epoxiconazole. The results consistently demonstrated that all tested application rates of fenpicoxamid and florylpicoxamid effectively controlled CLS in sugar beet, exhibiting a clear dose–response relationship. Disease severity, as measured by the area under the disease progress curve (AUDPC), was significantly correlated with yield reduction but showed no significant association with root sugar content. Moreover, data from both study years indicated that picolinamide fungicides applied at a rate of 75 g ai/ha significantly outperformed difenoconazole (100 g ai/ha) in controlling the CLS of sugar beet. Additionally, higher application rates of picolinamides at 100–150 g ai/ha outperformed epoxiconazole at 125 g ai/ha in disease suppression. Fenpicoxamid is currently registered for use in cereals within Europe, and outside of Europe in Banana against Black Sigatoka (eff. Mycosphaerella fijiensis). Florylpicoxamid, while not yet registered in Europe, is undergoing approval processes in various countries worldwide for a range of crops and is continually being evaluated for potential market introduction. Additional details regarding the efficacy of florylpicoxamid against CLS in sugar beet were presented at ‘The 10th International Conference on Agricultural and Biological Sciences (ABS 2024, Győr-Hungary)’ in 2024. Full article

Soybean (Glycine max (L.) Merr.) is one of the most profitable crops among the legumes grown worldwide. The occurrence of rust epidemics, caused by Phakopsora pachyrhizi, has greatly contributed to yield losses and an abusive use of fungicides. Within this context, this study investigated the potential of using a phosphite of nickel (Ni) and potassium (K) [referred to as induced resistance (IR) stimulus] to induce soybean resistance against infection by P. pachyrhizi. Plants were sprayed with water (control) or with IR stimulus and non-inoculated or inoculated with P. pachyrhizi. The germination of urediniospores was greatly reduced in vitro by 99% using IR stimulus rates ranging from 2 to 15 mL/L. Rust severity was significantly reduced from 68 to 78% from 7 to 15 days after inoculation (dai). The area under the disease progress curve significantly decreased by 74% for IR stimulus-sprayed plants compared to water-sprayed plants. For inoculated plants, foliar concentrations of K and Ni were significantly higher for IR stimulus treatment than for the control treatment. Infected and IR stimulus-sprayed plants had their photosynthetic apparatus (a great pool of photosynthetic pigments, and lower values for some chlorophyll a fluorescence parameters) preserved, associated with less cellular damage (lower concentrations of malondialdehyde, hydrogen peroxide, and anion superoxide) and a greater production of phenolics and lignin than plants from the control treatment. In response to infection by P. pachyrhizi, defense-related genes (PAL2.1, PAL3.1, CHIB1, LOX7, PR-1A, PR10, ICS1, ICS2, JAR, ETR1, ACS, ACO, and OPR3) were up-regulated from 7 to 15 dai for IR stimulus-sprayed plants in contrast to plants from the control treatment. Collectively, these findings provide a global picture of the enhanced capacity of IR stimulus-sprayed plants to efficiently cope with fungal infection at both biochemical and physiological levels. The direct effect of this IR stimulus against urediniospores’ germination over the leaf surface needs to be considered with the aim of reducing rust severity. Full article

Fungal diseases are a yield-limiting factor for wheat. Their management in organic production systems is one of the prevailing challenges because it must be based mainly on indirect measures through agricultural practices. Variety mixtures are one of these practices, a concept that has been demonstrated to improve several factors affecting yield. Recently, it has become a practice that enables sustainability in agriculture. Our research aim is to evaluate the capacity of this practice to control three fungal diseases (foliar and ear) on durum wheat. This study was conducted over two consecutive years (2019 and 2020) at two locations: a certified organic farm in the Benslimane region (2019) and the National School of Agriculture farm in Meknes (2020). Four durum wheat varieties (Isly, Tarek, Karim, and Nassira) were used to create the mixture. The parameters that were monitored were the disease severity, the grain yield, and its components. The analysis of variance for the three fungal diseases’ severity was significant. The variety that showed resistance to all diseases was the Isly variety, and the most susceptible variety was the Nassira variety. The resistance of the other varieties to the diseases was variable from one year to the other. The mixture showed average severity values. It allowed a reduction in the severity of leaf rust of 47% during the first year and 30% during the second year compared to the most susceptible variety (Nassira). In the case of HLB (helminthosporiosis leaf blight), it reduced the disease by 47% during the first year and 34% during the 2020 season. For ear disease, Fusarium head blight (FHB), the reduction was 68% during the year 2019 and 49% during 2020. The mixture also ensured yield stability between the two trial years (1.66 t ha⁻¹ and 1.54 t ha⁻¹). Full article

Antimicrobial properties of the new strains of micro-organisms isolated from natural sources of various ecological niches in the Moscow region and the Republic of Tatarstan were studied. Antifungal activity of isolates was detected in a test culture of toxin-producing microscopic fungi that can cause animal and plant diseases: Aspergillus flavus, Candida albicans, Fusarium oxysporum and Penicillium spp. Of the 46 studied micro-organisms of genera Bacillus, Lactobacillus, Lactococcus and Streptomyces isolates, there are four strains (Bacillus subtilis, Lactobacillus plantarum, Propionibacterium freudenreichii and Streptomyces spp.) that showed an ability to produce biologically active metabolites with a pronounced antimicrobial potential against phytopathogenic fungi metabolites. Based on the selected four strains, a Bacterial product LRV composition has been created. Scots pine, pedunculate oak and small-leaved linden seedlings with single and double foliar treatment and Bacterial product LRV at a concentration of 10 mL/L led to an increase in the growth of the aboveground part by 31.8, 51.9 and 25.4%, respectively, and the underground part by 25.0, 37.2 and 25.7%, respectively, compared to the control. The weight of seedlings at the end of the study exceeded the control variant by an average of 26.0, 44.0 and 78.0%, respectively. Plant protection Bacterial product LRV use did not have a significant effect on the group of molds that caused the powdery mildew and Schütte disease damage to trees. The Biological product LRV provided plant protection from fungal diseases caused by Lophodermium pinastri Chev. and Microsphaera alphitoides. Full article

Nickel (Ni) is an essential micronutrient for plants, responsible for metabolizing urea nitrogen (urea-N) by urease and mitigating abiotic and oxidative stresses through the glyoxalase (Gly) and glutathione (GSH) cycles. However, excess Ni is toxic to flora at >100 mg kg⁻¹, except for hyperaccumulators that tolerate >1000 mg kg⁻¹ Ni. This review discusses the benefits of Ni nutrient management for soil fertility, improving food security, and minimizing adverse environmental impacts from urea overapplication. Many farming soils are Ni deficient, suggesting that applying 0.05–5 kg ha⁻¹ of Ni improves yield and urea-N use efficiency. Applied foliar and soil Ni fertilizers decrease biotic stresses primarily by control of fungal diseases. The bioavailability of Ni is the limiting factor for urease synthesis in plants, animal guts, and the soil microbiome. Improved urease activity in plants and subsequently through feed in livestock guts reduces the release of nitrous oxide and nitrite pollutants. Fertilizer Ni applied to crops is dispersed in vegetative tissue since Ni is highly mobile in plants and is not accumulated in fruit or leafy tissues to cause health concerns for consumers. New methods for micronutrient delivery, including rhizophagy, recycled struvite, and nanoparticle fertilizers, can improve Ni bioavailability in farming systems. Full article

The fungal pathogen Setosphaeria turcica causes northern corn leaf blight (NCLB) in maize, sorghum, and related grasses. NCLB is a serious fungal foliar disease of cultivated maize that causes devastating yield losses. S. turcica infects maize leaves by means of a specialized cell, the appressorium, but the regulatory mechanisms that underlie appressorium-mediated infection remain largely unknown. Many regulatory pathways and a large number of genes have been described in S. turcica, and many of these genes have been cloned. Characterization of such disease-related genes is important for understanding the biological mechanisms of interaction between pathogen and host and can guide the development of strategies for disease control. There is a significant level of concern regarding the possible dissemination of the S. turcica pathogen to regions where NCLB is not presently prevalent. This scenario is of considerable concern and necessitates immediate research intervention. The present review brings together information on the epidemiology and infection mechanisms of S. turcica. Full article

Diversification at the plot level, through the use of intercropping (mixtures of crops), is an alternative to the conventional system of intensive agriculture, based on monospecific, usually single-variety canopies. Intercropping has been shown to provide benefits in terms of disease control. However, competition phenomena and the heterogeneity of the associated crops raise new ecological questions, particularly with regard to the dynamics and evolution of parasite populations. No study has assessed the potential impact of these associations on the dynamics of pathogenic species complexes. Changes in the nutritional status of plants and therefore in their physiological susceptibility to infection within intercropping systems could contribute to an increased diversity of ecological niches and thus affect the composition of the parasitic complex and its spatiotemporal dynamics. In this review, focusing on foliar diseases of fungal origin, and after outlining some elements of the biology and epidemiology of these fungal diseases, we will (i) describe the mechanisms that contribute to the composition of disease clusters and that drive interactions, but we will also review the strategies that these foliar diseases have adopted to deal with these co-infections; (ii) define how intercropping can lead to changes in epidemic dynamics, in particular by presenting the mechanisms that have a direct and indirect effect on disease evolution; and (iii) present the approach that should be adopted to properly study intercropping correctly in a multi-infection situation. Full article