Search Results (124)

Vascular wilt caused by Fusarium oxysporum f. sp. physali (Foph) severely limits cape gooseberry (Physalis peruviana L.) production in Andean regions, where management options are restricted and largely dependent on fungicides. Silicon (Si) has been proposed as a sustainable strategy to enhance tolerance to vascular pathogens; however, its role in the cape gooseberry–Foph pathosystem remains unknown. This study evaluated the effects of soil and foliar Si applications on disease development and physiological responses in cape gooseberry plants under greenhouse conditions. Three soil doses and three foliar doses were tested, including inoculated and non-inoculated controls without treatment. Si significantly reduced disease progression, decreasing the area under the disease progress curve (AUDPC) and disease severity index, with efficacy values of up to 69% in inoculated plants, particularly at 8 g kg⁻¹ soil application. Si also reduced vascular browning and mitigated pathogen-induced physiological impairment by maintaining higher stomatal conductance, relative chlorophyll content, maximum quantum efficiency of photosystem II, and plant growth. These findings indicate that Si, especially when soil-applied, enhances physiological tolerance to Foph and represents a promising complementary tool for its integrated management. Full article

Palm oil is a major agricultural commodity and an important economic driver in Asia. However, the sustainability and productivity of this crop are constantly threatened by a range of pathogenic fungi, especially Ganoderma boninense. Therefore, this study aimed to develop an eco-friendly hexaconazole-loaded nanoemulsion (Hexa-NE) for effective and targeted fungicide delivery while reducing environmental and health impacts. The optimized Hexa-NE formulation was evaluated for particle size, polydispersity index (PDI), zeta potential, pH, viscosity, and morphology using Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). Fungicide release, stability, and antifungal activity were conducted to assess the overall efficacy and performance of the formulation. The Hexa-NE exhibited particle size of 105.8 nm, a PDI of 0.358, a zeta potential of −53.53 mV. The formulation remained stable over three months of storage. It also demonstrated favourable physicochemical properties including low viscosity (30.24 mPa·s), low surface tension (23.87 mN/m), and suitable pH (6.14) for foliar application. TEM and SEM analyses confirmed spherical droplets and revealed significant hyphal damage to G. boninense. The antifungal test showed a higher inhibition of 97.1% at 0.1 µM of Hexa-NE as compared to hexaconazole solution which only 40% at the same concentration. Release studies exhibited a sustained release of hexaconazole, which may prolonged fungicidal activity. In conclusion, Hexa-NE showed promising laboratory-scale antifungal performance against G. boninense. These findings support its potential for further investigation as a nanoformulated fungicide for future greenhouse and field evaluations. Full article

Brown spot, caused by the fungus Bipolaris oryzae, has led to significant yield losses in rice production worldwide. This study hypothesized that azelaic acid (AzA) could reduce brown spot symptoms in rice leaves by potentiating biochemical defense reactions. A 2 × 2 factorial experiment was arranged in a completely randomized design with five replications per sampling time. The factors studied were plants sprayed with water (control) or AzA (10 mM; 7.5 mL per plant), either non-inoculated or inoculated with B. oryzae. In the in vitro assay, conidia exposed to AzA solutions at rates of 2.5, 5, 7.5, and 10 mM and to the fungicide solution did not form germ tubes compared to those in the control (water) treatment. The area of fungal colonies on oat–agar medium was reduced for the fungicide and AzA (rates increasing from 2.5 to 10 mM) treatments compared to the control (water) treatment. The EC₅₀ value was 3.8 mM AzA. Brown spot severity significantly decreased by 57, 48, 52, and 58% at 36, 60, 84, and 108 h after inoculation (hai) for AzA-sprayed plants compared to water-sprayed ones. The area under brown spot progress curve significantly decreased by 53% for AzA-sprayed plants compared to water-sprayed ones. Greatest activities of defense-related enzymes (chitinase at 108 hai, β-1,3-glucanase at 60 hai, phenylalanine ammonia-lyase at 60 and 108 hai, and lipoxygenase at 84 and 108 hai), a higher concentration of lignin at 84 and 108 hai, and a more robust antioxidative metabolism (higher activities of ascorbate peroxidase at 36 hai, catalase at 84 and 108 hai, and superoxide dismutase at 84 hai) were obtained for AzA-sprayed infected plants. The higher concentration of the superoxide anion radical in AzA-sprayed infected leaves helped to intensify the cell defense reactions against fungal infection and had a fungistatic effect against its hyphae and conidia germination. The findings of this study provide valuable insights into using AzA to potentiate foliar defense reactions in rice plants to hamper the infection by B. oryzae. Full article

The foliar pathogens of wheat, particularly Zymoseptoria tritici and Pyrenophora tritici-repentis, represent a significant threat to yield. We used a SEIR (Susceptible–Exposed–Infected–Removed) model to quantify epidemic dynamics based on different fungicide application strategies, focusing on the daily dynamic growth rate r(t) (net infection increase) and the removal rate γ(t) (loss infectious tissue) after BBCH 37. In Scenario A (treatment of seed with Systiva^®), the r(t) of Z. tritici was positive only during the early phase of the epidemic, followed by progressive suppression over time, while the r(t) for P. tritici-repentis remained negative throughout. Scenario B (seed treatment combined with foliar propiconazole) resulted in uniformly negative r(t) values for both pathogens, indicating stronger and sustained suppression. These findings highlight the practical utility of epidemic growth rate modeling for evaluating fungicide strategies and support integrated seed + foliar applications as a robust approach to disease management in wheat. Full article

Asian soybean rust (ASR), caused by Phakopsora pachyrhizi (Syd.), poses a serious threat to global soybean production. The main approach to managing this disease has been through repeated fungicide applications which have reduced efficacy due to fungicide resistance. Recently, spray-induced gene silencing (SIGS) through exogenous application of double-stranded RNA (dsRNA) has emerged as a promising approach for plant disease management. In the present study, twelve different dsRNAs targeting genes important for P. pachyrhizi urediniospore germination, infection of the host plant or resistant to commonly used fungicides were produced in Escherichia coli on a large scale. Nine of these dsRNAs significantly reduced ASR severity (by 24.0% to 81.1%) and fungal biomass (50.5% to 83.1%) compared to the control when applied as a foliar spray in our growth chamber studies. Three of the most effective dsRNAs targeting an acyltransferase (ACE), cytochrome B (CYTB1) and a reductase (S12) also significantly reduced disease severity (78.2 to 82.3%) and fungal growth (79.8 to 85.4%) compared to the control in the greenhouse studies. Further investigation of the P. pachryrhizi urediniospore germination and hyphal growth in the presence of these dsRNAs in vitro revealed these dsRNAs reduced the spore germination rate from 72.1% to 0.0–26.6% at 4.5 h and hyphal growth from 254.0 µm to 2.7–40.5 µm at 9 h, with dsRNA targeting the S12 gene being the most effective. These results highlight the potential of SIGS using selected dsRNAs as a sustainable strategy for managing ASR through suppressing urediniospore germination and hyphal growth. Full article

Analysis of the apple tree rhizosphere and phylloplane microbiota revealed the presence of pathogenic and conditionally pathogenic micromycetes: Penicillium, Cladosporium, Fusarium, Mucor, Trichotecium, Alternaria. The application of microbial fertilizers (MFs)—Azafok, Enzymocid, and Nitragin—reduced their abundance in the soil. This occurred due to the beneficial bacteria contained in the biopreparations (Bacillus spp., Bacillus aryabhattai, Pseudomonas fluorescens, Bradyrhizobium japonicum), which possess fungicidal activity and the ability to improve the mineral nutrition of plants, thereby enhancing their immune status. Nitragin also reduced the colonization of leaves by pathogenic fungi. The greatest reduction in contamination was achieved by the combined application of MFs with foliar feeding using mineral substances, particularly when using Azafok. The influence of MFs on the state of the epiphytic microbiota is associated with their indirect action through the activation of the host plant’s functional activity and the stimulation of its defense mechanisms. The MFs introduced into the soil stimulated an increase in the content of nitrogen, phosphorus, potassium, and calcium in the leaves. We also noted the influence of MFs on modifying the effect of foliar feeding on the nutrient content in the leaves. The leaf nitrogen content with the combined application of soil-applied Azafok and FF was lower than with soil application alone. Furthermore, the use of foliar fertilizing reduced the phosphorus and potassium content in the leaves against the background of Azafok and Enzymocid, although the relative level of these nutrient contents remained very high. Only the application of foliar fertilizing against the background of Nitragin stimulated an increase in the phosphorus and potassium content in the leaves. Further research is needed to clarify the nature of this modification. Full article

Gray mold caused by Botrytis cinerea poses a major threat to tomato production worldwide. This study investigated the antifungal efficacy and defense-inducing potential of Agricultural Jiaosu (AJ), a fermented bioproduct derived from agricultural residues. In vitro, AJ exhibited strong inhibitory activity against B. cinerea (IC₅₀ = 3.9%), primarily through acidic metabolites (pH < 4.2) that disrupted fungal membranes and suppressed antioxidant enzymes, while later-stage inhibition was maintained by Acetobacter populations (6.7 × 10⁷ copies μL⁻¹) through competition for nutrients. In vivo, foliar application of 0.5% AJ significantly promoted tomato growth and enhanced resistance by stimulating antioxidant (SOD, CAT, POD) and defense-related (PAL, PPO) enzyme activities, reducing oxidative damage and lowering gray mold incidence by 55%. Collectively, AJ exerts a dual mode of action that combines direct pathogen suppression with activation of host systemic resistance. These results highlight AJ as a sustainable, residue-free biocontrol solution that offers an environmentally friendly alternative to chemical fungicides for effective management of gray mold in tomato cultivation. Full article

Chemical fungicides play a key role in protecting crops, but their use can result in environmental problems. We tested a novel fungicide, composed of endophytic microorganisms, for its effect on wheat yield, grain quality, plant development, and the rhizosphere microbiome, assessed by 16S and ITS metabarcoding. The fungicide increased the grain yield, the effect being similar to a well-known commercial bacterial fungicide, without affecting its quality. Ascomycota, Zygomycota and Mucoromycota together comprised 80% of the mycobiome. Mucoromycota/Mucoromycetes/Rhizopodaceae/Rhizopus arrhizus were significantly decreased. The dominant (≥10%) bacterial phyla were Pseudomonadota, Acidobacteriota, Bacteroidota and Actinomycetota, but their fungicide-related differences were small or random. Different modes of fungicide application (seeds only, seeds plus one or two foliar applications) had no effect on wheat characteristics. Neither of the fungicide’s agents (Raoultella ornithinolytica and Pantoea allii) were found in the rhizosphere. The changes in the mycobiome seemed more pronounced than in the bacteriobiome. The proposed preparation is concluded to have good prospects as a fungicide. However, the low species/strain resolution of the DNA metabarcoding did not allow us to fully interpret shifts in the microbiome diversity, both agronomically and environmentally. These aspects need more comprehensive investigation, using methodology with higher species resolution. Full article

A growing interest in aerial drone applications has led to the European regulatory proposal 2022/0196/COD, which considers aerial spraying in steep-slope vineyards safer for human health and the environment. Nevertheless, disease control in perennial crops by aerial applications remains under-investigated. This study aims to identify suitable Plant Protection Products (PPPs) for aerial application in vineyards and analytical methods to quantify PPP deposits. A standardized protocol for controlling grapevine downy mildew was developed, testing Metalaxyl-M and copper-based fungicides’ efficacy and foliar depositions. As Italian law prohibits aerial application, an Unmanned Aerial Spray System (UASS) constrained to the ground simulated aerial spray. Leaves were sampled on predetermined days after treatment application for both fungicides’ efficacy evaluation and deposit quantification. Metalaxyl-M applied from UASS showed an efficacy comparable to ground sprays at pre- and post-flowering (≈70%), while copper efficacy from UASS was lower (≈47–63%) at each stage. Aerial sprayings resulted in higher deposits in the upper canopy, potentially explaining the lower efficacy of copper fungicides, while Metalaxyl-M’s systemicity partially compensated for the uneven vertical distribution, improving disease control. This study established a methodology for aerial PPP testing in vineyards, further studies are needed to confirm these findings across different years and locations. Full article

Biofungicide products are a rapidly expanding sector of the plant protection market. Powdery mildew of tomato (Solanum lycopersicum), caused by Erysiphe neolycopersici, can result in significant yield loss in high tunnel (HT) tomato production. Copper-based fungicides are heavily used in HTs, especially those in certified organic production, to control powdery mildew and other fungal diseases. Reliance on copper can lead to its overuse, subsequent resistance development in pathogens, and accumulation of high amounts of copper in the soil. In this study, we evaluated two bio-product alternatives to copper for efficacy against powdery mildew in an organic HT tomato production system over three growing seasons. These alternatives were a commercial biofungicide containing Bacillus subtilis GB03 and a filtered and unfiltered microbial fermentation product (F-MFP and UF-MFP, respectively). UF-MFP was a proprietary blend of yeast cell walls and inactive fermentation media, whereas F-MFP was processed to remove any particles larger than 0.2 μm. The HT-grown tomato plants were inoculated with E. neolycopersici (10⁴ conidia/mL) and three to five foliar applications of biofungicide were made per season. Powdery mildew severity was lower with MFPs compared to the water-treated inoculated treatment and B. subtilis, although this was not always statistically significant (p = 0.05). At assessment dates where statistically significant difference among treatments were observed, the MFP treatments were generally equivalent to the cuprous oxide standard. These results suggest that MFP may be a suitable alternative or alternation partner to copper-based products currently in use in HT tomato systems affected by powdery mildew. Full article

Postharvest losses in onion (Allium cepa L.) bulbs constitute a major economic challenge globally, primarily driven by fungal pathogens and premature sprouting during long-term storage. Addressing these issues with effective preharvest strategies is critical for market stability and supply chain integrity. This study evaluated the effects of two preharvest fungicide strategies, i.e., T1 (dimethomorph + pyraclostrobin) and T2 (metalaxyl + mancozeb + copper oxychloride), on the crop yield, postharvest quality, and sprouting behavior of dried onion bulbs. Both treatments significantly reduced the incidence of foliar disease in the field and improved the crop yield of commercial bulbs compared to the control in two consecutive seasons. T1 achieved the highest yield (~76 and 88 t ha⁻¹ in ‘Mata Hari’ and ’Recas’ onions). During storage at 20 °C for 84 days, in the ‘Mata Hari’ cultivar, the T1 bulbs exhibited the lowest weight loss and respiration rate, the lowest sprouting incidence (1%), and superior firmness retention and higher total soluble solids. In contrast, control bulbs exhibited accelerated weight loss and tissue degradation, with up to 95% sprouting. Pyruvic acid content, an indicator of pungency, was highest in T1 bulbs and increased significantly in sprouted controls, likely due to internal enzymatic activation and tissue senescence. The fungicides indirectly delayed dormancy release by delaying sprouting and internal stem axis formation. Overall, T1 was the most effective strategy for preserving onion quality during storage without using synthetic sprout inhibitors. These findings support the integration of specific fungicide programs into preharvest management to improve onion storability, reduce postharvest losses, and maintain commercial value in intermediate-dormancy dried onion cultivars, such as ‘Mata Hari’. Full article

Neopestalotiopsis zimbabwana is an emerging phytopathogen with multiple hosts. Considering the environmental, toxicological, and resistance issues linked to synthetic fungicides, Origanum vulgare L. essential oil (OEO) was evaluated through in vitro, in vivo, and in silico approaches. The pathogen, isolated from Watsonia borbonica L., was molecularly identified. Gas chromatography–mass spectrometry (GC–MS) analysis showed hexadecanoic acid (15.98%), dodecanoic acid (15.74%), terpinen-4-ol (11.61%), and thymol (7.65%) as the main components. In vitro assays determined a minimum inhibitory concentration (MIC) of 30% OEO and a minimal fungicidal concentration (MFC) of 60% OEO. Growth chamber trials demonstrated that preventive sprays maintained 0% foliar damage—similar to Captan^®—while controls reached ≈98%; suspending applications after week 4 resulted in ≈45% damage by week 8. These results confirm that OEO lacks systemic residual activity, acting only as a protectant within preventive integrated pest management (IPM) schemes. Docking to cytochrome b (protein data bank, PDB: 5TL8) indicated strong binding of α-farnesene (−7.638 kcal·mol⁻¹), isoterpinolene (−6.944), and α-terpineol (−6.918), suggesting disruption of mitochondrial respiration via Complex III. OEO represents a promising eco-friendly alternative for managing N. zimbabwana under controlled conditions and reducing reliance on synthetic fungicides. Full article

Soybean rust, caused by Phakopsora pachyrhizi, is a major foliar disease that often escapes fungicide control, necessitating alternative strategies. We investigated whether phyllosphere arthropods, such as mites and thrips, facilitate the secondary dispersal of the mycoparasitic fungus Simplicillium under controlled conditions. Detached soybean leaves inoculated with P. pachyrhizi were subjected to either arthropod-exposed or arthropod-excluded treatments. Simplicillium isolates were significantly more abundant in the presence of arthropods. Molecular identification revealed identical ITS genotypes of S. lamellicola from both infected pustules and thrips, indicating vector-mediated fungal transmission. While some Simplicillium strains persisted epiphytically without vectors, their spread was minimal. These results highlight a promising approach to enhance the effectiveness of Simplicillium-based biocontrol through natural arthropod-mediated dissemination, warranting field validation of this self-disseminating strategy. Full article

Sclerotinia sclerotiorum (S. sclerotiorum), a necrotrophic phytopathogen, causes sclerotinia stem rot (SSR) in many crops like oilseed rape, resulting in severe economic losses. Developing eco-friendly compound fungicides has become a critical research priority. This study explored the combination of sodium selenite and cuminic acid to screen for the optimal mixing ratio and investigate its inhibitory effects and mechanisms against S. sclerotiorum. The results demonstrated that synergistic effects were observed with a 1:3 combination ratio of sodium selenite to cuminic acid. After treatment with the selenium compound agent, ultrastructural observations revealed that the hyphae of S. sclerotiorum became severely shriveled, deformed, and twisted. The agent significantly reduced oxalic acid production and the activities of polymethylgalacturonide (PMG) and carboxymethylcellulose enzymes (Cx), while increasing the exocytosis of nucleic acids and proteins from the mycelium. Foliar application of the selenium compound agent significantly reduced lesion areas in rapeseed. Combined with the results of transcriptome sequencing, this study suggests that the compound agent effectively inhibits the growth of S. sclerotiorum by disrupting its membrane system, reducing the activity of cell wall-degrading enzymes, and suppressing protein synthesis, etc. This research provides a foundation for developing environmentally friendly and effective fungicides to control S. sclerotiorum. Full article

Old vineyards in production in the Pampa biome have high levels of metals, such as copper (Cu), zinc (Zn), and manganese (Mn). The high metal contents in the soil can damage the growth and development of the cover plant species that cohabit the vineyards. However, it is possible to define the critical toxicity level (CTL) of metals in soil and tissue in order to monitor and define possible strategies for reducing metal inputs and selecting more tolerant species. This study aimed to define the CTL of Cu, Zn, and Mn in the soil and plant tissue of plants present between the rows of vineyards with different cultivation histories in the Pampa biome in South America. For this purpose, soil and plant tissue samples were collected in a native field area (NF), without agricultural cultivation and in two vineyards, vineyard 1 (V1) and vineyard 2 (V2), both with a history of fungicide application. To define the CTL, the foliar concentrations and soil contents of Cu, Zn, and Mn were correlated with the dry mass production of the shoot. The CTLs for Cu, Zn, and Mn in the soil were set at 15, 3.0, and 35 mg kg⁻¹, respectively. In the tissue, CTLs for Cu, Zn, and Mn were estimated at 75, 77, and 380 mg kg⁻¹, respectively. The contents of Cu, Mn, and Zn in the soil of the vineyards are above the CTL. The concentrations of the metals in the tissue varied, with samples above the CTL for Cu and Zn in the vineyards. The values of Cu, Zn, and Mn in NF are below the CTL in soil and tissue. The high contents of Cu, Zn, and Mn in the soil and tissue limited the dry mass production of the plants between the rows of vineyards. Full article