Native Trichoderma spp. as biocontrol agents against common beans anthracnose

Native strains of Trichoderma in vineyard soil represent an opportunity for reducing the incidence of grapevine trunk diseases (GTDs) in vineyards. Moreover, its relationship with the environment (physicochemical soil characteristics and farming management practices) remains unclear. In the current study, a survey was carried out on farming management used by viticulturists, and soil samples were studied to analyze their physicochemical properties and to isolate Trichoderma strains. Later, statistical analyses were performed to identify possible correlations between Trichoderma populations, soil management and soil characteristics. In addition, in vitro tests, including antibiosis and mycoparasitism, were performed to select those Trichoderma strains able to antagonize Phaeoacremonium minimum. In this study a positive correlation was found between the iron content and pH in the soil, and a lower pH increases Trichoderma populations in soils. Vineyard management also affects Trichoderma populations in the soil, negatively in the case of fertilization and tillage and positively in the case of herbicide spraying. Two Trichoderma native strains were selected as potential biocontrol agents (Trichoderma gamsii T065 and Trichoderma harzianum T087) using antibiosis and mycoparasitism as mechanisms of action. These results led to the conclusion that native Trichoderma strains hold great potential as biological control agents and as producers of secondary metabolites.

Background: Fusarium wilt caused by Fusarium oxysporum f. sp. ciceris significantly limits chickpea (Cicer arietinum L.) productivity in semi-arid regions. Native Trichoderma spp. offer potential for sustainable disease management and growth promotion. Methods: Nineteen Trichoderma isolates were obtained from chickpea rhizosphere soils in Marathwada, Maharashtra, during the rabi season, 2023-24. Isolates were screened against the pathogen using dual culture assays and eight promising isolates were identified by ITS sequencing. A pot experiment with chickpea cv. BDNGK-798 was conducted using seed and soil applications of Trichoderma, followed by pathogen inoculation. Growth parameters, wilt incidence and micronutrient (Zn, Cu, Fe, Mn) uptake were recorded 65 days after sowing. Result: Eight isolates of Trichoderma significantly suppressed Fusarium wilt while enhancing germination, seedling vigour, growth, yield and micronutrient content. T. yunnanense (CTA2, CTP4) and T. pleuroticola (CTB2) were the most effective, demonstrating strong dual potential as biocontrol agents and biofertilizers under controlled conditions, indicating their applicability for improving chickpea productivity in stressed environments.

This study examines the in vitro antagonistic effect of three native Trichoderma sp. isolates originating from saffron corms, against three Fusarium species plants (F. pseudograminearum, F. moniliforme and F. oxysporum) known to cause rotting in the bulbs and roots of saffron. To introduce Trichoderma into a preventive control program, the Trichoderma isolates were tested by in direct confrontation and volatile substances production. They demonstrated colonization percentages ranging from 50% to 79.6%, significantly inhibiting the mycelial growth and spore germination of pathogenic species, with inhibition rates ranging from 53% to 79% and 51% to 79%, respectively. However, indirect confrontation through the production of diffusible substances showed low inhibition of mycelial growth and spore germination for all pathogenic isolates studied, not exceeding 28.47% and 20.5%, respectively. This study discusses the potential of using Trichoderma as biocontrol agents against a wide range of bioaggressors.

Native Trichoderma spp. were isolated from agricultural fields in several regions of Ecuador. These isolates were characterized via morphological observation as well as molecular phylogenetic analysis based on DNA sequences of the rDNA internal transcribed spacer region, elongation factor-1α gene and RNA polymerase subunit II gene. Fifteen native Trichoderma spp. were identified as T. harzianum, T. asperellum, T. virens and T. reesei. Some of these strains showed strong antagonistic activities against several important pathogens in Ecuador, such as Fusarium oxysporum f. sp. cubense (Panama disease) and Mycosphaerella fijiensis (black Sigatoka) on banana, as well as Moniliophthora roreri (frosty pod rot) and Moniliophthora perniciosa (witches’ broom disease) on cacao. The isolates also showed inhibitory effects on in vitro colony growth tests against Japanese isolates of Fusarium oxysporum f. sp. lycopersici, Alternaria alternata and Rosellinia necatrix. The native Trichoderma strains characterized here are potential biocontrol agents against important pathogens of banana and cacao in Ecuador.

To evaluate the biocontrol of Rhizoctonia solani fungal infection in common bean (Phaseolus vulgaris) by using native Trichoderma spp. from northwestern Argentina. Eight Trichoderma isolates were assessed for their ability to inhibit AG4 R. solani growth through dual culture. All Trichoderma isolates suppressed fungal growth at 4 days post-inoculation, and completely overgrew on it by exerting high antagonism. Mainly, T. afroharzianum isolates (Th15, Th45, and Th51) reduced the root rot severity (42%-51%) in white common bean (cv. Alubia), and increased the germination index, fresh weight, and root lengths in bioassays (inoculated and non-inoculated with the pathogen). Conidial suspensions of T. afroharzianum isolates (Th15, Th28, and Th51) decreased R. solani infection by 30%-50% in white common bean seedlings and increased stem and root development in greenhouse assays. Moreover, liquid culture of T. afroharzianum Th15 also showed antifungal activity on the growth and infection of R. solani in black common bean (cv. Leales 15). Th15 colonization competed effectively with R. solani by reducing the disease severity index and the inoculum of R. solani in bean roots (the latter of which was assessed by qPCR). Trichoderma afroharzianum Th15 is a biological agent with the potential to protect two cultivars of common bean from the pathogenic attack of R. solani.

ABSTRACTThe objective of the present study was to examine a biological model under greenhouse conditions for the bioremediation of atrazine contaminated soils. The model consisted in a combination of phytoremediation (using Phaseolus vulgaris L.) and rhizopheric bio-augmentation using native Trichoderma sp., and Rhizobium sp. microorganisms that showed no inhibitory growth at 10,000 mg L−1 of herbicide concentration. 33.3 mg of atrazine 50 g−1 of soil of initial concentration was used and an initial inoculation of 1 × 109 UFC mL−1 of Rhizobium sp. and 1 × 105 conidia mL−1 of Trichoderma sp. were set. Four treatments were arranged: Bean + Trichoderma sp. (B+T); Bean + Rhizobium sp. (BR); Bean + Rhizobium sp. + Trichoderma sp. (B+R+T) and Bean (B). 25.51 mg of atrazine 50 g−1 of soil (76.63%) was removed by the B+T treatment in 40 days (a = 0.050, Tukey). This last indicate that the proposed biological model and methodology developed is useful for atrazine contaminated bioremediation agricultural soils, which can contribute to reduce the effects of agrochemical abuse.

Phytophthora root rot caused by the pathogen Phytophthora cinnamomi is one of the main causes of oak mortality in Mediterranean open woodlands, the so-called dehesas. Disease control is challenging; therefore, new alternative measures are needed. This study focused on searching for natural biocontrol agents with the aim of developing integrated pest management (IPM) strategies in dehesas as a part of adaptive forest management (AFM) strategies. Native Trichoderma spp. were selectively isolated from healthy trees growing in damaged areas by P. cinnamomi root rot, using Rose Bengal selective medium. All Trichoderma (n = 95) isolates were evaluated against P. cinnamomi by mycelial growth inhibition (MGI). Forty-three isolates presented an MGI higher than 60%. Twenty-one isolates belonging to the highest categories of MGI were molecularly identified as T. gamsii, T. viridarium, T. hamatum, T. olivascens, T. virens, T. paraviridescens, T. linzhiense, T. hirsutum, T. samuelsii, and T. harzianum. Amongst the identified strains, 10 outstanding Trichoderma isolates were tested for mycoparasitism, showing values on a scale ranging from 3 to 4. As far as we know, this is the first report referring to the antagonistic activity of native Trichoderma spp. over P. cinnamomi strains cohabiting in the same infected dehesas. The analysis of the tree health status and MGI suggest that the presence of Trichoderma spp. might diminish or even avoid the development of P. cinnamomi, protecting trees from the worst effects of P. cinnamomi root rot.

Trichoderma spp. were isolated from soils of Chhattisgarh and screened for antagonistic activity against Alternaria brassicae using dual culture and inverted plate methods. Among the isolates, Trichoderma harzianum (T6) showed the strongest inhibition of A. brassicae, with 53.80% inhibition in dual culture and 42.83% through volatile compounds. For mass application, T. harzianum was multiplied and combined with organic amendments (Karanj, Mahua, and Mustard cakes at 3% w/w) and applied to both pot and field soils. The effectiveness of treatments was evaluated by assessing percent disease index (PDI) on mustard at 75 and 90 days after sowing (DAS). The integrated treatment of Trichoderma with organic amendments significantly reduced disease severity compared to Trichoderma alone, demonstrating a synergistic effect. The native isolates T6 and T4 exhibited strong antagonism via mycoparasitism and volatile compounds, highlighting their potential as effective biocontrol agents. Overall, the integrated use of Trichoderma and organic amendments offers a promising strategy for managing Alternaria leaf spot in mustard.

BackgroundThe Egyptian cotton leafworm (Spodoptera littoralis) is a highly destructive, pesticide-resistant pest affecting over 80 economically important crops across the Mediterranean and African regions. While chemical insecticides offer temporary relief, their long-term use poses environmental and health risks, and resistance development reduces their effectiveness. Biological control using entomopathogenic fungi, particularly Trichoderma spp., offers a sustainable alternative. Traditionally, it is used against plant pathogens, Trichoderma harzianum, T. viride, T. asperellum, and T. longibrachiatum have also shown insecticidal potential through the production of compounds like peptaibols, gliotoxins, and chitinases, and by inducing systemic resistance in plants. However, the entomopathogenic potential of native Trichoderma isolates in Egypt remains undiscovered, and field performance is often inconsistent. This study aims to identify and evaluate native Trichoderma strains against S. littoralis and enhance their biocontrol efficacy through interspecific protoplast fusion a promising parasexual technique for strain improvement.ResultsMultilocus sequence analysis targeting the tef1-α and rpb2 genes identified the isolates as T. harzianum, T. asperellum, and T. longibrachiatum. Phylogenetic analysis clustered the isolates into three well-distinctive clades corresponding to these species. Among the tested isolates, Tricho19 (T. longibrachiatum), Tricho5 (T. asperellum), and Tricho30 (T. harzianum) demonstrated the highest extracellular chitinase activity and larval mortality in oral bioassays against S. littoralis. Interspecific protoplast fusion led to the generation of fusants with significantly enhanced chitinase production and insecticidal activity relative to their parental strains. Greenhouse assays confirmed the superior performance of fusant Fus8, which exhibited the highest larval mortality and antifeedant activity, closely approaching the efficacy of a chemical insecticide.ConclusionInterspecific protoplast fusion significantly improved the entomopathogenic performance of Trichoderma strains against S. littoralis. The enhanced activity of fusant strains, particularly Fus8, highlights the potential of this cost-effective strategy to generate improved biocontrol agents. These findings contribute to the development of sustainable pest management alternatives that can reduce reliance on chemical pesticides in agriculture.

Mycoparasitism by Clonostachys byssicola and Clonostachys rosea on Trichoderma spp. from cocoa (Theobroma cacao) and implication for the design of mixed biocontrol agents

Root rot in Lycium barbarum, an economically vital crop, is a critical barrier to its sustainable development in China. To elucidate the underlying micro-ecological mechanisms, this study aimed to characterize and compare the rhizosphere microbial communities of healthy and diseased plants from the Qaidam Basin. We employed PacBio full-length amplicon sequencing to analyze bacterial and fungal populations, complemented by network analysis and in vitro antagonistic assays. The results indicated that while microbial species richness was similar, the community structures of healthy and diseased soils were fundamentally different, suggesting that the disease is primarily driven by microbial dysbiosis rather than species loss. Healthy soil was enriched with beneficial Trichoderma, whereas diseased soil was dominated by the pathogen Fusarium, with an abundance 6.7 times higher than that in healthy soil. Network analysis revealed the healthy fungal community was significantly more stable (modularity index: 0.818) than the diseased network (0.4131), where Fusarium occupied a core hub position. Crucially, Trichoderma strains isolated from healthy soil exhibited strong antagonistic activity against Fusarium, with an average inhibition rate exceeding 75%. This study identifies Fusarium as the key pathogen of Goji root rot and native Trichoderma as a potent biocontrol agent, providing a scientific basis for a sustainable, micro-ecological control strategy.

Aim: To evaluate the selected native isolates of Trichoderma spp. of Kasaragod district for abiotic stress tolerance and compatibility assessment with other biocontrol agents. Study Design: CRD. Place and Duration of Study: Department of Plant Pathology, College of Agriculture, Padannakkad, between November 2023 and November 2024. Methodology: The selected Trichoderma isolates Tr-5, Tr-12, Tr-41, Tr-43 (Trichoderma asperellum) and Tr-40 (Trichoderma lixii) were subjected to various abiotic stresses, namely low (4°C, 10°C and 15°C) and high (30°C, 45°C and 55°C) temperatures, salinity (0.5M, 1.5M and 2.5 M NaCl) and drought (10%, 30% and 40% PEG). The PDA was embedded with different NaCl and PEG concentrations to test the salinity and drought tolerance. After 4 days of inoculation (DAI), radial growth of Trichoderma isolates in treatments and controls was recorded. The compatibility of these Trichoderma isolates was checked with the other bio-control agents viz., Pseudomonas fluorescens, Metarhizium anisopliae, Lecanicillium lecanii and Beauveria bassiana using the dual culture technique. Results: In the temperature tolerance study, the selected isolates did not show any radial growth at 4°C, 10°C, 45°C, and 55°C.At 15°C, slight mycelial growth was observed, and the optimal range was found to be 30°C for good mycelial growth. The tolerance to salinity was up to 0.5M NaCl, but only in Tr-5 (0.83cm), Tr-12 (0.91), and Tr-40 (0.8) isolates; the mycelial growth was observed at 1.5M NaCl. At 10% PEG, the radial growth of isolates was on par with the control. Upon increasing concentration, radial growth of Trichoderma isolates was decreased/ absent along with sporulation. In the compatibility study, Trichoderma isolates were found to be compatible with P. fluorescens, M. anisopliae, L. lecanii and B. bassiana. But with fungal biocontrol agents, only Tr-40 showed incompatibility with M. anisopliae (66.67%), L. lecanii (33.58%), but was compatible with B. bassiana. Conclusion: In this study, all five native Trichoderma isolates, Tr-5, Tr-12, Tr-40, Tr-41 and 43 showed high tolerance to abiotic stresses at an optimum range of temperature (30oC), NaCl (0.5M), and PEG (10%). The isolates of Trichoderma spp. were compatible with bacterial and fungal bio-control agents except Tr-40.

Sclerotiniasclerotiorum, the causal agent for white mold (Sclerotinia stem rot), is a devastating fungal pathogen. Currently, Sclerotinia is most commonly managed using the chemical fungicide which can lead to Sclerotinia resistance development, impacting biodiversity and interfering with key ecosystem services. In this regards, field experiments were conducted during 2017-18 planting seasons to evaluate the efficacy of different components viz. sawdust burning, stable bleaching powder, fungal and bacterial bio-control agents, chemical fungicide Rovral 50 WP and integration of different components for the management white mold disease of bush bean, mustard and garden pea in three different locations viz. in the field of Plant Pathology Division, Bangladesh Agricultural Research Institute, Joydebpur, Gazipur, Regional Agricultural Research Station (RARS), Burirhat, Rangpur and RARS, Ishurdi, Pabna, respectively. The results showed that different treatments displayed varying levels of effectiveness against the disease. All the treatments gave satisfactory reduction of white mold disease development and increased plant growth as well as yield of bush bean, mustard and garden pea. Among the treatments, integration of saw dust burning + soil amendments with Trichoderma based bio-fungicide + bacillus based bio-control agents + application fungicide Rovral 50 WP is the best treatment which reduced 97.49%, 77.72%, 72.26% white mold disease incidence and 84.61%, 81.14%, 71.01% white mold disease severity of mustard, bush bean and garden pea, respectively and increasing plant growth parameter as well as 52.16%, 27.74%, 36.97% yield of mustard, bush bean and garden pea, respectively. Application of only fungicide Rovral 50 WP also better treatment in reduction of white mold disease incidence and disease severity and increasing plant growth parameter as well as increasing yield of mustard, bush bean and garden pea. Soil amendment with fungal or bacterial bio-control agents also gave satisfactory results in reduction of white mold disease incidence and disease severity and increasing plant growth parameter as well as increasing yield of mustard, bush bean and garden pea. It could be concluded from the obtained results that integration between bio-control agents as a soil treatment and foliar application chemical fungicide might be useful as a good tool for controlling white mold disease caused by S.sclerotiorum and obtained higher yield of bush bean, mustard and garden pea under field condition.

Endophytic bacteria, from the desert spurge (Euphorbia antiquorum) enhance nutrients uptake and suppress root rot in the common bean

Biological control using fungi of the Trichoderma genus has been gaining increasing prominence as a sustainable alternative to synthetic pesticides, particularly due to its ability to suppress phytopathogens and promote plant growth. While the beneficial role of Trichoderma species is well established, research involving native strains from Brazilian biomes remains limited. The present work comprised the investigation of 55 isolates of Trichoderma spp., isolated from the soil or endophytic from the plant species natives to the Pantanal and Cerrado of Mato Grosso do Sul (Brazil), regarding their capacity to inhibit the growth and spread of the phytopathogen Sclerotinia sclerotiorum (Lib.) de Bary. The results from confrontation assays (15.74-30.04% growth of S. sclerotiorum), paired plate cultures (5.76-39.53% growth of S. sclerotiorum), and cell wall-degrading enzyme (CWDEs) activity assays-whose activities ranged from 8.791 to 197.593 Umg-1 for glucanase, 0.059-333.864 Umg-1 for NAGase, 0.082-37.110 Umg-1 for acid phosphatase, 1.234-45.716 Umg-1 for chitinase, and 3.261-304.807 Umg-1 for protease-were used to select Trichoderma spp. Five strains were selected: Trichoderma sp. T24, Trichoderma zelobreve T26, Trichoderma longibrachiatum T44, T. zelobreve T53, and Trichoderma sp. T55. Except for strain T44, all other strains demonstrated effectiveness in biological control of S. sclerotiorum (disease severity index ≤25%) and plant growth promotion in Phaseolus vulgaris L. cultivation (vigor index ≥268). The volatile organic compounds (VOCs) produced by five Trichoderma spp. strains post-exposure to S. sclerotiorum were analyzed by Gas Chromatography-Mass Spectrometry (GC/MS) were identified, among these VOCs with known antifungal activity, such as β-cedrene (6), β-funebrene (7), and α-acoradiene (12). Trichoderma sp. T24, T. zelobreve T53, and Trichoderma sp. T55 have potential as biocontrol agents against S. sclerotiorum and as biostimulants, increasing plant growth and development.