Search Results (12)

The potential of invasive plants to serve as reservoirs for plant pathogenic fungi has been confirmed, but studies examining the seasonal effects on the community structure and transmission patterns of leaf pathogens within invasive plant populations remain scarce. In this study, we characterised the seasonal dynamics of pathogenic fungal communities in the leaf tissue of the invasive plant A. adenophora via culture-dependent and culture-independent methods. The study confirmed that fresh leaves of A. adenophora accumulate diverse pathogenic fungi, including Colletotrichum, Epicoccum, Toxicocladosporium, Mycosphaerella and Didymella. These genera are globally distributed and act as pathogens for a wide range of wild plants and economic crops. The pathogenic fungal communities exhibited seasonal dynamics, though the magnitude of change was less pronounced than that of the overall fungal community. Among four common environmental factors, namely, temperature, relative humidity, wind speed and precipitation, temperature had a greater effect on the overall community than the other environmental factors, whereas precipitation had the least effect. However, relative humidity has the strongest effect on the pathogenic fungal community; moreover, relative humidity distinctively affects the same species occurring in different microenvironments. Most foliar pathogenic fungi are actively transmitted in spring and autumn, and very few genera can transmit across all seasons. Moreover, most fungal genera can transmit from fresh leaves to dead leaves, suggesting that most foliar fungal pathogens associated with A. adenophora are likely necrotrophic. Our study strongly confirms the potential of the invasive plant A. adenophora to act as a reservoir of pathogenic fungi and provides preliminary insights into their potential transmission patterns. These findings underscore that, under suitable climatic and environmental conditions, A. adenophora may pose a latent risk of triggering disease transmission within ecosystems. 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

The productivity and quality of strawberries in southern Brazil are affected by the lack of cultivars adapted to different regions and by their susceptibility to diseases. This study aims to evaluate the resistance of cultivars and genotypes to mycosphaerella leaf spot (MLS) and powdery mildew (PM) and the quantitative and qualitative fruit agronomic parameters (FAP) of strawberries in southern Brazil during the 2019/2020 and 2020/2021 growing seasons. The incidence and severity of MLS and PM were evaluated from the beginning of symptoms appearances until harvest. Cultivars and genotypes were compared based on the area under the incidence (AUIDPC) and severity (AUSDPC) disease progress curves and the quantitative and qualitative FAP. The data were subjected to analysis of variance, and multivariate analysis was performed using principal component analysis (PCA). The cultivars Irma, Bellalinda, Kiara, Jonica, and Pircinque exhibited the lowest values of AUIDPC and AUSDPC, demonstrating the highest resistance to MLS and PM. The cultivars Kiara, Jonica, and Pircinque, along with genotype FRF LAM 119.1, showed the best qualitative and quantitative FAP. However, the FRF LAM 119.1 genotype exhibited the highest values of AUIDPC and AUSDPC, indicating high susceptibility to MLS and PM. CPA data indicated that the cultivars Kiara, Jonica, and Pircinque had the highest level of resistance, which was associated with the highest total fruit yield and the best fruit quality in terms of skin color and flavor balance. Kiara, Jonica, and Pircinque proved to be good options for strawberry production in southern Brazil, combining resistance to MLS and PM with good FAP. Full article

The Sigatoka disease complex (SDC), caused by Mycosphaerella fijiensis (Mf) and M. musicola (Mm), comprises the most destructive fungal leaf streak and spot diseases of commercial banana crops worldwide. In Brazil, the site-specific succinate dehydrogenase inhibitor (SDHI) fungicides labeled for SDC management since 2014 present a high risk for the emergence of resistance if deployed intensively and solo. Our study determined the levels of sensitivity to boscalid and fluxapyroxad in four populations of the SDC pathogens sampled in 2020 from three distinct geographical regions under contrasting fungicide programs. Resistance, defined as EC₅₀ values exceeding 20 µg mL⁻¹, was prevalent at 59.7% for fluxapyroxad and 94.0% for boscalid. Only 1.5% of isolates exhibited sensitivity to both fungicides. We also assessed the changes in the corresponding fungicide target protein-encoding genes (SdhB, C, and D). None of the target site alterations detected were associated with reduced sensitivity. A second SdhC paralog was also analyzed, but target alterations were not found. However, MDR (multidrug resistance) was detected in a selection of isolates. Further monitoring for Sdh target mutations will be important, but an important role for other resistance mechanisms such as the presence of additional Sdh paralogs and MDR cannot be ruled out. These results highlight the importance of implementing sound anti-resistance management strategies when SDHI fungicides are deployed for the management of SDC. Full article

The efficiency of plant-growth-promoting rhizobacteria (PGPR) may not be consistently maintained under field conditions due to the influence of soil microbial communities. The present study aims to investigate their impact on three PGPR-based biofertilizers in wheat. We used the PGPR Paenibacillus sp. strain B2 (PB2), PB2 in co-inoculation with Arthrobacter agilis 4042 (Mix 2), or with Arthrobacter sp. SSM-004 and Microbacterium sp. SSM-001 (Mix 3). Inoculation of PB2, Mix 2, and Mix 3 into non-sterile field soil had a positive effect on root and aboveground dry biomass, depending on the wheat cultivar. The efficiency of the PGPR was further confirmed by the protection they provided against Mycosphaerella graminicola, the causal agent of Septoria leaf blotch disease. PB2 exhibited protection of ≥37.8%, while Mix 2 showed ≥47.9% protection in the four cultivars tested. These results suggest that the interactions between PGPR and native soil microbial communities are crucial for promoting wheat growth and protection. Additionally, high-throughput sequencing of microbial communities conducted 7 days after PGPR inoculations revealed no negative effects of PB2, Mix 2, and Mix 3 on the soil microbial community structure. Interestingly, the presence of Arthrobacter spp. appeared to mitigate the potential negative effect of PB2 on bacterial community and foster root colonization by other beneficial bacterial strains. Full article

Fungi are associated with the European cranberry (Vaccinium oxycoccos L.) and play important roles in plant growth and disease control, especially in cranberry yields. This article presents the results of a study which was aimed to investigate the diversity of fungi found on different clones and cultivars of the European cranberry grown in Lithuania, causing twigs, leaf diseases and fruit rots. In this study seventeen clones and five cultivars of V. oxycoccos were selected for investigation. Fungi were isolated via the incubation of twigs, leaves and fruit on a PDA medium and identified according to their cultural and morphological characteristics. Microscopic fungi belonging to 14 genera were isolated from cranberry leaves and twigs, with Physalospora vaccinii, Fusarium spp., Mycosphaerella nigromaculans and Monilinia oxycocci being the most frequently isolated fungi. ‘Vaiva’ and ‘Žuvinta’ cultivars were the most susceptible to pathogenic fungi during the growing season. Among the clones, 95–A–07 was the most susceptible to Phys. vaccinii, 95–A–08 to M. nigromaculans, 99–Ž–05 to Fusarium spp. and 95–A–03 to M. oxycocci. Microscopic fungi belonging to 12 genera were isolated from cranberry berries. The most prevalent pathogenic fungi M. oxycocci were isolated from the berries of the cultivars ‘Vaiva’ and ‘Žuvinta’ and clones 95–A–03 and 96–K–05. Full article

Yellow and black Sigatoka, caused by Mycosphaerella fijiensis and M. musicola, respectively, are the most important worldwide foliar diseases of bananas. Disease control is heavily dependent on intensive fungicide sprays, which increase selection pressure for fungicide resistance in pathogen populations. The primary objective of this study was to assess the level and spread of resistance to quinone-outside inhibitors (QoI—strobilurin) fungicides in populations of both pathogens sampled from banana fields under different fungicide spray regimes in Southeastern Brazil. Secondly, we aimed to investigate when QoI resistance was confirmed if this was associated with the target-site alteration G143A caused by a mutation in the mitochondrial encoded cytochrome b gene. QoI resistance was detected in fungicide treated banana fields, while no resistance was detected in the organic banana field. A total of 18.5% of the isolates sampled from the pathogens’ populations were resistant to QoI. The newly described M. thailandica was also found. It was the second most abundant Mycosphaerella species associated with Sigatoka-like leaf spot symptoms in the Ribeira Valley and the highest level of QoI resistance was found for this pathogen. The G143A cytochrome b alteration was associated with the resistance to the QoI fungicides azoxystrobin and trifloxystrobin in M. fijiensis, M. musicola and M. thailandica strains. In order to reduce resistance development and maintain the efficacy of QoI fungicides, anti-resistance management strategies based on integrated disease management practices should be implemented to control the Sigatoka disease complex. Full article

The field pea has both semi-leafless (SL) and leafed (L) types. Mixing these two types together might improve yield by optimizing pea solar radiation interception, reducing lodging, and decreasing disease. However, an optimum mixing ratio has not yet been established, since previous studies mixed two leaf types from two separate varieties. This study used four near-isogenic pairs of pea genotypes differing only in leaf type to determine the optimal mixing ratio for yield and agronomic traits. Two leaf types were mixed at seeding in five mixing ratios: 0:100, 50:50, 67:33, 83:17, and 100:0 SL/L. With precise UAV quantification of canopy height (r² = 0.88, RMSE = 2.6 cm), the results showed that a ratio of over 67% semi-leafless pea had a 10% greater lodging resistance when compared to the leafed monoculture. For mycosphaerella blight and Uromyce viciae-fabae rust diseases, the 83:17 mixture decreased disease severity by 4% when compared with the leafed monoculture. Regression analysis of yield estimated that the 86:14 ratio provided an 11% increase to the leafed monoculture, but there was no increase compared with the semi-leafless monoculture. Mixing the two types in a high semi-leafless ratio can reduce leafed lodging and prevent yield loss but does not increase the overall yield over the semi-leafless monoculture. Full article

As the population ages globally, there seem to be more people with Alzheimer’s disease. Unfortunately, there is currently no specific treatment for the disease. At present, Huperzine A (HupA) is one of the best drugs used for the treatment of Alzheimer’s disease and has been used in clinical trials for several years in China. HupA was first separated from Huperzia serrata, a traditional medicinal herb that is used to cure fever, contusions, strains, hematuria, schizophrenia, and snakebite for several hundreds of years in China, and has been confirmed to have acetylcholinesterase inhibitory activity. With the very slow growth of H. serrata, resources are becoming too scarce to meet the need for clinical treatment. Some endophytic fungal strains that produce HupA were isolated from H. serrate in previous studies. In this article, the diversity of the endophytic fungal community within H. serrata was observed and the relevance to the production of HupA by the host plant was further analyzed. A total of 1167 strains were obtained from the leaves of H. serrata followed by the stems (1045) and roots (824). The richness as well as diversity of endophytic fungi within the leaf and stem were higher than in the root. The endophytic fungal community was similar within stems as well as in leaves at all taxonomic levels. The 11 genera (Derxomyces, Lophiostoma, Cyphellophora, Devriesia, Serendipita, Kurtzmanomyces, Mycosphaerella, Conoideocrella, Brevicellicium, Piskurozyma, and Trichomerium) were positively correlated with HupA content. The correlation index of Derxomyces with HupA contents displayed the highest value (CI = 0.92), whereas Trichomerium showed the lowest value (CI = 0.02). Through electrospray ionization mass spectrometry (ESI-MS), it was confirmed that the HS7-1 strain could produce HupA and the total alkaloid concentration was 3.7 ug/g. This study will enable us to screen and isolate the strain that can produce HupA and to figure out the correlation between endophytic fungal diversity with HupA content in different plant organs. This can provide new insights into the screening of strains that can produce HupA more effectively. Full article

While Black Sigatoka Leaf Disease (Mycosphaerella fijiensis) has arguably been the most important pathogen affecting the banana industry over the past 50 years, there are no quantitative estimates of what risk factors determine its spread across the globe, nor how its spread has affected banana producing countries. This study empirically models the disease spread across and its impact within countries using historical spread timelines, biophysical models, local climate data, and country level agricultural data. To model the global spread a empirical hazard model is employed. The results show that the most important factor affecting first time infection of a country is the extent of their agricultural imports, having increased first time disease incidence by 69% points. In contrast, long distance dispersal due to climatic factors only raised this probability by 0.8% points. The impact of disease diffusion within countries once they are infected is modelled using a panel regression estimator. Findings indicate that under the right climate conditions the impact of Black Sigatoka Leaf Disease can be substantial, currently resulting in an average 3% reduction in global annual production, i.e., a loss of yearly revenue of about USD 1.6 billion. Full article

This article presents the results of a study that examines the loss of biomass and energy, per hectare, caused by Teratosphaeria leaf disease (TLD) in Eucalyptus globulus short rotation forestry. The 95 Eucalyptus globulus taxa analyzed are from seeds of open pollinated families of both Spanish and Australian origin. Tree height and diameter were measured and the crown damage index (CDI) assessed at 27 months of age. Taxa that have a certain tolerance to the disease have been identified. The taxon identified as code 283 is the one that shows lower CDI (42%) and with an average volume that exceeded 0.017 m³ at 27 months of age. Biomass losses were determined for each fraction of dry biomass of the tree (leaves, branches, twigs and bark) based on CDI. These losses were translated into terms of energy lost per hectare, depending on the CDI. A comparison was then carried out between the productivity of Eucalyptus globulus exhibiting various levels of TLD severity and poplar and willow clones used for bioenergy in Europe. In our region, the results show that despite the losses of biomass associated with TLD, Eucalyptus globulus remains competitive as long as CDI values are lower than 56%. Full article

Eucalyptus globulus is widely planted in temperate regions to produce pulp for its high performance but few studies of the impact of Mycosphaerella Leaf Disease (MLD) have been documented. This study aimed to explore and provide knowledge on disease in the management of young Eucalyptus globulus stands in the north of Spain. The influences of subspecies, cloning, and fertilization on the degree of severity of the disease were analyzed. The study was conducted with different material plants of Eucalyptus globulus, of Australian origin, from other sources, open-pollinated families, clones, and families of controlled pollination. Each series tested different vegetal material, except for a number of control codes that were used as reference samples for MLD evaluation. Severity, height at which foliage changes from juvenile to adult, total height, and volume were all measured. There were significant correlations in the average MLD severity of families and provenances obtained from the different trials. ANOVA revealed important differences between subspecies of E. globulus. A correlation was found between the percentage of adult leaf and the severity. There were differences in the impact of MLD between plant material non-selected and selected by its tolerance (p < 0.0001). There was a significant effect on the severity between mature cuttings and families from seed non-selected in their tolerance to MLD. Their tolerance was lower than that achieved from seed selected by its tolerance to MLD. Genetic selection was shown as the best strategy since there are individuals exceptionally tolerant to MLD. Full article