Rhizoctonia solani is a significant soil-borne pathogenic fungus that poses a significant threat to the economically important agricultural crops. 4-(Diethylamino)salicylaldehyde (DSA) is a secondary metabolite produced by Streptomyces sp. KN37, which has antifungal activity, meanwhile its inhibitory mechanism is still unclear. In this study, we explored the antifungal efficacy of DSA and its potential mechanism of inhibiting R. solani. It was found that DSA exhibited significant antifungal activity against six tested plant pathogenic fungi, with R. solani being the most sensitive (EC50 = 26.904 mu g/mL). Notably, DSA effectively reduced the mycelial mass and inhibited sclerotia germination, demonstrating a good control efficacy of cucumber damping-off disease. Morphological observation showed that DSA significantly disrupted the shape and ultrastructure of the mycelium. Transcriptomic and metabolomic analyses revealed that DSA impacted the integrity of the cell membrane, redox processes, and energy metabolism in R. solani. The results of fluorescence staining, relative conductivity, H2O2 content, and antioxidant enzyme activity showed that the accumulation of ROS in hypha cells after DSA treatment possibly resulted in damage to cell membrane integrity. Furthermore, the reduction in ATP content, along with decreased ATPase and citrate synthase activity, indicates that energy production may be inhibited. Molecular docking analysis further showed that DSA may competitively inhibit citrate synthase, thereby inhibiting cell energy production and ultimately inducing apoptosis. Our study provides new insights into the potential mechanism by which DSA inhibits the mycelial growth of R. solani.

The common pine sawfly, Diprion pini (Linnaeus, 1758) (Hymenoptera: Diprionidae), is a well-known defoliating pest of various pine forests almost all over the world, including Europe. It can cause damage to many pine species but usually opts for Pinus sylvestris Linnaeus and P. nigra subsp. laricio (Poiret) Maire. The prohibition of the use of chemical insecticides in forests (at least for T & uuml;rkiye) has led to the fact that other control methods have come to the fore in the control of this pest. In this respect, biological control agents, which are eco-friendly and can persist in the field over time, providing long-term control for plant protection, have an important potential in the control of D. pini. Therefore, in this study, entomopathogenic fungi were isolated from pine forest soils and identified by gene sequencing and phylogenetic analysis. Ten isolates (DP-37, DP-38, DP-45, DP-46, DP-49, DP-53, DP-54, DP-57, DP-58 and DP-63) were identified as Beauveria pseudobassiana, four isolates (DP-35, DP-41, DP-52, and DP-61) were identified as B. bassiana, and only one isolate was identified as Metarhizium robertsii (DP-15). All isolates were tested against the larvae of the pest under laboratory conditions, and the highest mortality and mycosis values (96.6% and 63.3%, respectively) were obtained from B. pseudobassiana DP-57. This isolate was also tested against the pest under outdoor conditions using different conidial concentrations. Based on probit analysis, the LC50 and LC90 values were estimated to be 1.309 x 107 and 1.21 x 1010 conidia/ml, respectively. The results showed that B. pseudobassiana DP-57 could be a good candidate in the biological control of D. pini.

Understanding the mechanisms that give rise to obstacles in the continuous cultivation of C. pilosula is essential for addressing or mitigating these challenges. The findings of this study suggest that repeated cultivation significantly reduced the content of polysaccharide in roots, and significantly increased the dead seedling rate in the field. The vascular bundles of the affected plant were extensively colonized by fungi. Furthermore, the root vascular bundles exhibit significant woodiness and corkiness, accompanied by cellular fractures and structural collapse. It was determined that the pathogenic endophyte is Fusarium oxysporum, and the exacerbated disease manifestation corresponds to an acute wilting type. Additionally, the root-zone soil microorganisms Cladosporium austroafricanum, Fusarium foetens, Fusarium petersiae, and Acaulium retardatum may significantly contribute to the yield-reducing phenomenon associated with continuous cropping. The proliferation of pathogenic bacteria during continuous cultivation initiates a complex interaction mechanism between the host plant and these pathogens. This process is characterized by a rapid increase in calcium ion (Ca2+) concentration, which subsequently leads to an upsurge in reactive oxygen species (ROS), particularly manifested as elevated levels of hydrogen peroxide (H2O2). Additionally, this response triggers thickening of cell walls and other immune mechanisms aimed at inhibiting the invasion of pathogenic bacteria. At the same time, to prevent ROS from inducing oxidative damage and triggering oxidative stress, there is a notable increase in both antioxidant enzyme activity and antioxidant substances content.

Pioneering results of seed-potato health improvement and the suppression of soil-borne infection during the potato production by the preplant coating of tubers with an azoxystrobin-loaded degradable polymer film coating are presented. The film coating was applied to the surface of potato tubers by spraying with a 1% solution of the degradable polymer poly(3-hydroxybutyrate) in dichloromethane mixed with azoxystrobin. The film coating did not damage the tubers or reduce germination. The half-life of the polymer coating in field soil was 25 days. The film degraded gradually from potato planting to the beginning of flowering, ensuring long-term delivery of the fungicide to the plants. In the experimental group, a more effective reduction in the total number of rhizospheric soil fungi, including plant pathogens Alternaria alternata and Fusarium oxysporum, was revealed, compared with the preplant treatment of tubers with the commercial fungicide azoxystrobin (comparison group). The healing effect of the fungicide-loaded coating led to an improvement in the quality of the potato crop. In the experimental group, the total yield and the share of marketable tubers exceeded those of the comparison group by 5.6 t/ha and 8%, respectively. The proportion of Fusarium infected tubers was 8.5% in the experimental group versus 12.1% in the comparison group. The fungicidal effect of a long-term degradable polymer film coating with azoxystrobin was more successful than traditional treatment of tubers with a solution of this fungicide. Thus, the proposed approach is promising for the protection of seed potatoes.

The large pine weevil (Hylobius abietis L.) is a major pest in European and Asian coniferous forests, particularly in managed plantations where clear-felling practices create ideal conditions for its population growth. Traditional management practices involving synthetic insecticides have limited efficacy in terms of reducing pest populations and pose environmental risks. This study evaluated the effectiveness of a wild entomopathogenic fungus (EPF) and the commercial entomopathogenic nematode Steinernema carpocapsae (EPN) as biological control agents (BCAs) against H. abietis in clear-felled spruce plantations in Wales and Scotland. Field trials used a randomised block design with three treatments (EPN full dose, EPF full dose and a combination of EPF+EPN at half doses each) compared to a control. Emergence trapping and destructive sampling were employed to assess treatment efficacy. All treatments significantly reduced weevil emergence, with the mixed treatment showing the greatest impact. Destructive sampling revealed strong associations between treatment type and infection outcomes in H. abietis, with a small but significant relationship between weevil developmental stages and infection types. Importantly, the treatments had no significant impact on the total abundance or taxon richness of non-target invertebrates. These findings suggest that wild EPFs alone and combined with EPNs are effective and environmentally safe alternatives to synthetic insecticides for managing H. abietis populations in managed forests.

Introduction: Fusarium-induced root rot of Carya cathayensis (C. cathayensis) is a typical soil-borne disease that has severely damaged the Carya cathayensis industry in China. Understanding the interaction among soil microbial communities, soil characteristics, and pathogenic bacteria is very important for the ecological prevention and control of Carya cathayensis root rot. Methods: We used Miseq Illumina high-throughput sequencing technology to study the microbial community in the rhizosphere soil of healthy and diseased C. cathayensis, quantified the abundance of bacteria, fungi, and pathogenic fungi, and combined these with soil chemistry and enzyme activity indicators to analyze the characteristics of healthy and diseased rhizosphere soils. Results: We found that the pH, soil organic carbon(SOC), available nitrogen (AN), available phosphorus (AP), available potassium (AK),N-acetyl-beta-D-glucosaminidase (NAG) beta-glucosidase (BG), fungal gene copy number, bacterial community diversity and network complexity of the diseased soil were significantly lower (p < 0.05), while Fusarium graminearum copies number levels increased (p < 0.05). Additionally, the study found that healthy soils were enriched with beneficial bacteria such as Subgroup_7 (0.08%), MND1 (0.29%), SWB02 (0.08%), and Bradyrhizobium (0.09%), as well as potential pathogen-suppressing fungi such as Mortierella (0.13%), Preussia (0.03%), and Humicol (0.37%), were found to be associated with the growth and development of C. cathayensis. Discussion: In summary, this research comprehensively reveals the differences in environmental and biological factors between healthy and diseased soils, as well as their correlations. It provides a theoretical basis for optimal soil environmental regulation and the construction of healthy microbial communities. This foundation facilitates the development of multifaceted strategies for the prevention and control of C. cathayensis root rot.

In continuously cropped strawberry soil, a large population of the fungivorous nematode, Aphelenchus avenae, was observed to increase significantly over time. This nematode, which feeds on pathogenic fungi affecting strawberries, has significant potential as a biocontrol agent. The purpose of this article is to discuss the nematode's preference for fungi associated with strawberries and its impact on the growth of strawberry roots. With the exception of Trichoderma harzianum, most of the pathogenic fungi commonly found in strawberry soil, such as Fusarium oxysporum, Rhizoctonia solani, Verticillium, Phytophthora infestans, and Botrytis cinerea Pers. attracted A. avenae and supported their propagation. All treatments with A. avenae and the non-nematode control showed a consistent trend throughout strawberry development, indicating that a moderate amount of A. avenae does not adversely affect strawberry roots. Moderate and low levels of A. avenae significantly increased the activity of antioxidant enzymes, superoxide dismutase (SOD), and peroxidase (POD) in strawberry roots in all treatments during the entire growth stages. Also, the malondialdehyde (MDA) content of strawberry roots in all nematode treatments was lower than that in the no-nematode control. Despite an overabundance of A. avenae, which negatively affected the redox system balance of strawberry roots, A. avenae can protect the roots from pathogenic fungi by preventing infection and damage. These results lay the foundation for the potential use of A. avenae as a biological agent to control these pathogenic fungi in strawberry soil, in combination with the biological fungi (T. harzianum).

Insect pests are serious threats to agriculture, forestry, and human health because they damage crops and trees and spread diseases. Chemical insecticides control insect pests quickly and effectively, protecting crops. Environmental and health concerns arise from their use. Long-term exposure can cause pesticide-resistant insects, requiring stronger chemicals. Beneficial insects and wildlife may be harmed. Some chemical insecticides persist in the environment, causing long-term ecological damage. The present study was to isolate, identify, and characterize entomopathogenic fungi from the soil, evaluate their pathogenicity against major insect species, and evaluate the non-target effect on soil bioindicator species. Bioassay results show that Beauveria bassiana conidia are more pathogenic to all three species at 10 days after treatment, causing 100% mortality in Halyomorpha halys and Tenebrio molitor within 10 days. The lethal concentration showed lower LC50 values of 9.5 x 103 conidia/mL in H. halys, 2.6 x 103 conidia/mL in T. molitor, and 8.3x104 conidia/mL in P. japonica, B. bassiana treatment results showed a shortened insect life time LT50 of H. halys (6.0 days), T. molitor (5.3 days), and P. japonica (6.9 days). The present study concluded that B. bassiana fungi conidia are more efficient against three major insect pests.

Tenebrio molitor L., also known as the mealworm, is a polyphagous insect pest that infests various stored grains worldwide. Both the adult and larval stages can cause significant damage to stored grains. The present study focused on isolating entomopathogenic fungi from an infected larval cadaver under environmental conditions. Fungal pathogenicity was tested on T. molitor larvae and pupae for 12 days. Entomopathogenic fungi were identified using biotechnological methods based on their morphology and the sequence of their nuclear ribosomal internal transcribed spacer (ITS). The results of the insecticidal activity indicate that the virulence of fungi varies between the larval and pupal stages. In comparison to the larval stage, the pupal stage is highly susceptible to Metarhizium rileyi, exhibiting 100% mortality rates after 12 days (lethal concentration 50 [LC50] = 7.8 x 10(6) and lethal concentration 90 (LC90) = 2.1 x 10(13) conidia/mL), whereas larvae showed 92% mortality rates at 12 days posttreatment (LC50 = 1.0 x 10(6) and LC90 = 3.0 x 10(9) conidia/mL). The enzymatic analyses revealed a significant increase in the levels of the insect enzymes superoxide dismutase (4.76-10.5 mg(-1)) and glutathione S-transferase (0.46-6.53 mg(-1)) 3 days after exposure to M. rileyi conidia (1.5 x 10(5) conidia/mL) compared to the control group. The findings clearly show that M. rileyi is an environmentally friendly and effective microbial agent for controlling the larvae and pupae of T. molitor.

Ectropis grisescens is a notorious pest in tea plantations. The control of E. grisescens relies on synesthetic pesticides but the resurgence is always accompanied by increasing resistance. Therefore, it is crucial to use biological control to reduce the damage caused by E. grisescens. Here, we collected soil from a tea plantation, used Galleria mellonella as a bait insect and successfully isolated one entomopathogenic fungus. The isolated colony was initially identified as Cordyceps sp. using morphological observation. ITS-rDNA sequence amplification and sequencing, molecular database comparisons, and phylogenetic analysis proved this fungus as a new species and thus named Cordyceps sp. WZFW1. Further virulence test of Cordyceps sp. WZFW1 against E. grisescens was evaluated under laboratory conditions. Lethal concentration was 5.74 x 10(6) spore/mL with a confidence level of 2.32 x 10(6) similar to 1.79 x 10(7) and lethal time was 2.98 days at 10(6) spore/mL and 7.47 days at 10(7) spore/mL, indicating Cordyceps sp. WZFW1 was effective at controlling E. grisescens. Our findings are significant as they contribute to the application of new entomopathogenic fungi (EPF) species as biocontrol agents, promoting eco-friendly pest management practices.