Asperellum Strain Research Articles

Assessment of the Biocontrol Efficacy of Silver Nanoparticles Synthesized by Trichoderma asperellum Against Infected Hordeum vulgare L. Germination

This study investigated the biosynthesis, statistical optimization, characterization, and biocontrol activity of silver nanoparticles (AgNPs) produced by newly isolated Trichoderma sp. The Trichoderma asperellum strain TA-3N was identified based on the ITS gene sequence, together with its phenotypic characteristics (GenBank accession number: OM321439). The color change from light yellow to brown after the incubation period indicates AgNPs biosynthesis. The UV spectrum revealed a single peak with the maximum absorption at 453 nm, indicating that T. asperellum produces AgNPs effectively. A Rotatable Central Composite Design (RCCD) was used to optimize the biosynthesis of AgNPs using the aqueous mycelial-free filtrate of T. asperellum. The optimal conditions for maximum AgNPs biosynthesis (156.02 µg/mL) were predicted theoretically using the desirability function tool and verified experimentally. The highest biosynthetic produced AgNPs by T. asperellum reached 160.3 µg/mL using AgNO3 concentration of 2 mM/mL, initial pH level of 6, incubation time of 60 h, and biomass weight of 6 g/100 mL water. SEM and TEM imaging revealed uniform spherical shape particles that varied in size between 8.17 and 17.74 nm. The synthesized AgNPs have a Zeta potential value of −9.51 mV. FTIR analysis provided insights into the surface composition of AgNPs, identifying various functional groups such as N–H, -OH, C-H, C=O, and the amide I bond in proteins. Cytotoxicity and genotoxicity assays demonstrated that AgNPs in combination with T. asperellum can mitigate the toxic effects of Fusarium oxysporum on barley. This intervention markedly enhanced cell division rates and decreased chromosomal irregularities. The results indicate that AgNPs synthesized by T. asperellum show the potential as an eco-friendly and efficient method for controlling plant diseases. Further studies are necessary to investigate their possible use in the agricultural sector.

Potential of Trichoderma strains to positively modulate plant growth processes and bulb yield in Rabi onion

The use of beneficial microbes is hitherto known and constantly increasing in agriculture due to their positive impact on crop growth and yield, and their minimal negative impact on the environment. The objective of this study was to evaluate the impact of eight Trichoderma strains of diverse origin on crop growth and yield of onion under field conditions. The identity of the strains used in the current study was confirmed by ITS and Tef1 gene sequencing. Field experiments were conducted in the Rabi season for 2 years (2020–21, and 2022–23) to evaluate the effect of the application of eight different Trichoderma strains that were applied individually and separately as eight different treatments (T1–T8) in experimental plots. In the plant growth promotion assay conducted in vitro, all strains showed the ability to produce IAA (indole-3-acetic acid), with levels ranging from 23.52 μg/mL (T6) to 45.54 μg/mL (T3). Our results revealed that Trichoderma treated experimental plots displayed better growth indices (plant height, pseudostem diameter), RWC (Relative water content), leaf chlorophyll content, and yield-attributing features like biomass (bulb and root dry mass), bulb diameter, and harvested bulb yield compared to the untreated control plants. In terms of yield, the T2 strain exhibited the highest bulb yield consistently for both the years (2020–21 and 2022–23) followed by T3 being statistically at par with T5. Among all the evaluated Trichoderma strains, the strain T2 (OGRDT2) and T3 (GRDT1), taxonomically identified as Trichoderma longibrachiatum, registered bulb yield of 32.24 t/ha and 30.76 t/ha, respectively while T5 (GRDT3), identified as Trichoderma asperellum, registered 30.55 t/ha average yield for 2 years compared to 24.08 t/ha average yield recorded for untreated control plants with an increase of 34, 28 and 27%, respectively. Based on our findings, it is concluded that the T. longibrachiatum strains OGRDT2 (T2) and GRDT1 (T3), T. asperellum strain GRDT3 (T5) are the best inducers of the onion crop growth and yield in the Rabi season and would be explored further for its commercial application in onion farming.

Biocontrol potential of endophytic strains of Trichoderma asperellum against Fusarium oxysporum f. sp. cubense, subtropical race 4

In this work 10 endophytic Trichoderma asperellum strains were isolated from different banana genotypes and evaluated for its biocontrol potential against Fusarium oxysporum f. sp. cubense (Foc, subtroopical race 4 -SR4) the causal agent of Fusarium wilt of banana (FWB). All the T. asperellum strains showed biocontrol potential against Foc. the strains YG01F, M001F, and MC01F from Yamgambi No.2, Musa acuminata, and Musa acuminata subsp. malaccensis, respectively, exhibited the highest percentages of inhibition. Our results suggest a high and multifunctional diversity of culturable endophytic T. asperellum from Musa spp. roots, with a strong potential for new product developments to reduce FWB impact and enhance productivity in banana.

Comparing various bio-intensive pest management modules in rice

Rice is the key cereal crop in the tropics, supporting diverse pests and natural enemy populations. Recurrent pest outbreaks and yield losses led farmers to rely on extensive insecticide application, disturbing the stability of rice ecosystems and increasing residues in the harvestable products. A study has been conducted to assess the impact of various modules of Bio-Intensive Pest Management (BIPM) on its conservational potential and sustainability in comparison with Farmers’ Practices (FP) in Nalgonda district of Telangana state during kharif-2020. The BIPM practices included application of farm yard manure; rice husk ash; clipping of seedlings; alleyways and weekly release of Trichogramma japonicum in the main field; wet seed treatment and foliar application with Pseudomonas fluorescens (BIPM 1), Trichoderma asperellum strain TAIK1 (BIPM 2) and Bacillus cabrialesii strain BIK3 (BIPM 3). Whereas, FP 1 with need-based insecticide spraying and FP 2 with schedule-based insecticide spraying and Untreated control with (UC) with no intervention. The observations were taken by visual counts at 15-day intervals. The incidence of Cnaphalocrocis medinalis was highest in UC (9.50), followed by BIPM 1 (7.25) and least in FP 2 (2.50) whereas the highest mean population of Apanteles sp. was found in the untreated control (13.75), followed by BIPM 3 (9.50) and least in FP 2 (4.25). The Benefit Cost Ratios (BCR) of BIPM 3 (1.68) were highest followed by BIPM 1 (1.64) and least in FP 2 (1.40) elucidating that BIPM practices can be more economically feasible. The Shannon-Wiener Index for species diversity and species evenness was higher in BIPM treatments as compared to farmers’ practices indicating the potential of these BIPM treatments in natural pest control and maintaining crop ecosystem stability.

Antagonistic activity of Trichoderma asperellum against Fusarium species, chemical profile and their efficacy for management of Fusarium-root rot disease in dry bean.

Diseases caused by Fusarium pathogens lead to significant yield losses on many economically important crops. The purpose of this study was to evaluate the antagonistic capability and chemical profile of the bioagent Trichoderma asperellum against several Fusarium strains. The efficacy of this strain in reducing Fusarium-root rot disease in dry bean was also examined. The T. asperellum strain was identified based on sequencing the internal transcribed spacer (ITS) and tef1 gen regions of ribosomal DNA. Dual cultural assay demonstrated their antagonistic activity against the studied Fusarium strains due to the probable combination of competition, mycoparasitism and antibiosis. This strain was positive for cellulase, chitinase and protease activity. The crude extracts of T. asperellum significantly suppressed the growth of the tested Fusarium strains with inhibition zone values ranging from 7.3 to 19.7 mm and minimum inhibitory concentration (MIC) values ranging from 0.15 to 1.42 mg mL-1 . The gas chromatography-mass spectrometry (GC-MS) analysis of cell free supernatant and mycelial biomass of T. asperellum showed the presence of 27 and 21 compounds, respectively. The main compounds responsible for the bioactivity were butylated hydroxytoluene, hexadecanoic acid, 9-octadecenoic acid, ergosterol and hexadecanoic acid, ethyl ester. Trichoderma asperellum significantly increased plant emergence and reduced root rot caused by Fusarium solani in dry bean grown under glasshouse and field trials. Further, plant biomass and dry bean yield were higher in T. asperellum-treated plants than in control plants. Trichoderma asperellum was highly effective, through various mechanisms, against Fusarium strains especially F. solani which causes root rot in dry bean. © 2023 Society of Chemical Industry.

Characterization of Trichoderma strains for novel species-specific markers by multiplex PCR and antagonistic property against Alternaria ricini in castor (Ricinus communis L.)

The study aimed at characterizing six Trichoderma strains isolated from the rhizospheric soil of castor growing region of Telangana, India. Microscopic examination and sequencing of ribosomal DNA (rDNA) using internal transcribed spacer (ITS) and D1-D2 region-specific primers revealed them as members of Trichoderma sp. Whereas the phylogenetic analysis revealed four of those strains as Trichoderma asperellum, two strains were confirmed as Trichoderma harzianum with a high sequence similarity of >99%. Further, multiplex PCR results with Trichoderma-specific primers; TEF1 (translation elongation factor 1) and rpb2 (the second largest subunit of RNA polymerase II) gene-specific primers confirmed the findings resulting from the phylogenetic analysis. To develop a set of sequence characterized amplified region (SCAR) markers, these strains were screened with 185 random amplified polymorphic DNA (RAPD) primers. A pairwise comparison of correlation of coefficient values determined from the RAPD-based genetic similarity analysis revealed that TV3 and TS4 strains were closely related to each other (0.98) confirming them as T. harzianum while N13, 7316, TV5, and TV2B16 strains formed a different cluster with T. asperellum strains. A set of novel SCAR markers were developed to distinguish these two species, T. asperellum and T. harzianum including the reported Trichoderma strains as Ex-type strains. T. harzianum strains had extremely low sporulation ability to be tested for biocontrol properties. Of the four T. asperellum strains, 7316 followed by N13 demonstrated high antagonistic ability against the fungal pathogen, Alternaria ricini indicating these strains as potential biocontrol agents to limit Alternaria infection in castor.

Assessing rhizosphere Trichoderma asperellum strains for root colonizing and antagonistic competencies against Fusarium wilt through molecular and biochemical responses in castor

The study was aimed at identifying the effective strain(s) of Trichoderma asperellum to colonize castor roots, promote growth and limit pathogen infection. Two castor genotypes; DCS-107 and 48-1 varying for stress tolerance to Fusarium wilt were treated with four Trichoderma asperellum strains; 7316, N13, TV5 and TV2B16 to analyze root colonizing and antagonistic competencies. A significant decline in the colony-forming unit (CFU) counts was observed in Trichoderma-treated bulk and rhizosphere soil compared to controls indicating a high rhizosphere competence of the Trichoderma asperellum strains; 7316 followed by N13. These strains also showed high mycoparasitic propensity against Fusarium oxysporum through dual culture-confrontation and in-planta assays. Bio-priming with Trichoderma strains enhanced plant growth in the tolerant genotype, DCS-107 compared to the susceptible genotype, 48-1 suggesting differential responses of the host genotypes. An increase in shoot length by 46.2, 28.9 and 21.7% was observed upon treatment of DCS-107 genotype with the Trichoderma strains, 7316, N13 and TV5 respectively. Further, a quantitative polymerase chain reactions (qPCRs) of 13 stress and defence response genes revealed gene transcript reprogramming, causing a transient repression of the plant immune responses to enable root colonization. Further, biochemical analysis revealed higher antioxidant enzyme activity of catalase, superoxide dismutase and glutathione peroxidase and total phenol content in co-stressed conditions compared to the controls suggesting that Trichoderma confers protection against oxidative stress damage. Trichoderma strains, 7316, N13 and TV5, either individually or in combination could be utilized as potential biocontrol agents to enhance growth and confer resistance to wilt pathogen, Fusarium oxysporum ricini.

Efficacy of Biological Control Agents and Resistance Inducer for Control of Mal Secco Disease.

Mal secco, caused by Plenodomus tracheiphilus, is an economically important fungal vascular disease in citrus-growing countries of the Mediterranean basin. Preventing fungal infections usually requires a high number of copper treatments but European legislation imposes the minimization of their accumulation in soil. In our study, biological control agents (BCAs) and a plant resistance inducer (PRI), tested in four different experiments on citrus seedlings under controlled conditions, have resulted in promising strategies to control mal secco disease. Foliar (Experiment I) and soil (Experiment II) applications of two formulations of Bacillus amyloliquefaciens strain D747 (Amylo-X® LC and Amylo-X® WG) provided similar performances in reducing the disease amount (incidence and symptoms severity) over time compared to the untreated control, whereas copper hydroxide (Kocide Opti®) used as standard was the most effective treatment over time. In the third experiment, Pythium oligandrum strain M1 (Polyversum®) and Trichoderma asperellum strain ICC012 + Trichoderma gamsii strain ICC080 (Remedier®) were able to reduce disease incidence and symptoms severity compared to the untreated control. Remedier® provided the best performances in reducing the disease amount, whereas the Polyversum® application was the least effective treatment over time. The effectiveness of the Trichoderma spp. formulation in reducing P. tracheiphilus infections did not significantly differ from the standard copper compound (Kocide Opti®). Comprehensively, in the last experiment (IV), acibenzolar-S-methyl (ASM) alone and in mixture with metalaxyl-M proved as effective as B. amyloliquefaciens strain FZB24, with no dose-response relationships observed. These findings provide important insight for the integrated management of mal secco disease.

Trichoderma yunnanense and T. asperellum as potential biological agents for control of basal stem rot disease in oil palm

Basal Stem Rot (BSR) disease is a main constrain in oil palm cultivation. Ganoderma boninense is known as a causal agent of this disease. The intensity of BSR disease continues to increase in both the vegetative and generative phases of oil palm plantations and causes significant losses. Biological control is one of the BSR disease control techniques and is believed to be able to support sustainable oil palm cultivation. Trichoderma spp. is a group of fungal biological agents commonly used to control BSR disease. This study aims to obtain Trichoderma spp. isolates to be developed further as biocontrol agents for BSR disease. The research stages included isolation, morphology-based identification, antagonist potency testing, characterization, and identification with molecular technique. The results in this research obtained one isolate of Trichoderma strain TSU from oil palm plantation at Pematang Siantar Regency, and one isolate of Trichoderma strain TGLP from oil palm plantation at Musi Banyu Asin Regency, which inhibited the growth of G. boninense was 90.9 and 93.9% respectively through dual culture test. Inhibition tests by volatile compounds showed growth inhibition of G. boninense by both isolates were 55.2 and 70.6%. Both Trichoderma strains have the characteristics of producing chitinase, glucanase, and indole acetic acid. Furthermore, molecular identification showed that the Trichoderma strain TSU was similar to the Trichoderma yunnanense strain CBS121219 with an identity percentage of 99.11%, and Trichoderma TGLP as Trichoderma asperellum strain 1A4 with a percent identity of 99.65%. With their antagonistic ability and characteristics, the two Trichoderma spp. isolates have the potential to be further developed as biological agents for controlling BSR caused by G. boninense.

Trichoderma asperellum behave as antagonist to control leaf spot and flower blight of Marigold

Alternaria zinniae (Pape, 1942) causes leaf spot and blossom blight in marigolds, resulting in yield losses of 50-60 % in tropical and subtropical climates. Chemical controls can have a negative influence on ecosystems and agronomic control approaches are difficult to execute change to Chemical control are highly toxic, enhance biodegradation and cause environmental pollution after repeated use. Potential adverse effects on the earth and prolonged use have prompted a complete exclusion or limited utilization of most chemicals and an urgent need for eco-friendly and efficient tools. In vitro evidence for the possible use of Trichoderma spp. for biocontrol of marigold leaf spot and flower blight has been reported in previous investiga-tions. In this study, we used a dual culture approach to investigate the antagonistic and myco-parasitic properties of 4 Trichoderma asperellum strains against Alternaria zinniae in vitro.

Production of microsclerotia by Trichoderma asperellum through submerged liquid fermentation using low-cost nitrogen and carbon sources

The aim of this work is to optimize the nutritional conditions using low-cost carbon and nitrogen sources for microsclerotia (MS) production of two Brazilian Trichoderma asperellum strains (BRM-29576 and BRM-29104). A fractional factorial design was used to investigate five variables: carbon source, carbon concentration, nitrogen source, C:N ratio and fungal strain. In this study, the optimal nutritional conditions for improving MS yield were achieved using sucrose and autolyzed yeast, carbon concentration at 20 g L−1 and C:N ratio of 10:1 for the BRM-29104 strain, which outperformed the other strain and yielded up to 2.5 (±0.9) × 104 MS mL−1 within 7 days of fermentation. Sucrose and autolyzed yeast are two economically available carbon and nitrogen sources in Brazil that are suitable for MS production by T. asperellum BRM-29104. Vacuum filtration of MS biomass through nylon filter (200 mesh/74 μm) increased MS concentration, resulting in up to 1.8 (±0.2) × 105 MS g−1. Our results support a cost-efficient liquid medium to achieve high MS yields by strain BRM-29104 in combination with an easy method to harvest and concentrate MS from culture broth for further formulation development.

Trichoderma Asperellum strains as potential biological control agents against Fusarium verticillioides and Ustilago maydis in maize

ABSTRACT Globally, corn is the most economically important crop, surpassing crops such as wheat, rice and barley. However, the presence of pathogenic fungi associated with corn, have favoured the appearance of diseases that cause economic loss. Therefore, the aim of the present study is to assess the efficacy of treatments in vitro and in vivo with Trichoderma asperellum in controlling the disease severity and the yield reduction in corn plants caused by Fusarium verticillioides and Ustilago maydis. In vitro confrontation experiments demonstrated the high antagonistic capacity of the T. asperellum strains, which is able to reduce the radial growth of the pathogen’s colonies from 88.71% up to 100%. In the field experiments treatments 6 and 7, where T. asperellum was confronted with F. verticillioides and U. maydis, showed a significant reduction in the average damage of the disease by 8.3 ± 6.7 and 9.5 ± 3.0, and an increase in their grain yield by 4.43 ± 0.33 and 4.11 ± 0.15 t/ha, respectively. Similarly, the percentage of good ears of 66.75 ± 5.4 and 70.37 ± 5.4, obtained in treatments 6 and 7, was higher than those values obtained in treatments 2 and 3 without Trichoderma confrontation. These results indicate that the selected Trichoderma strains isolated from Zea mays could effectively control these phytopathogenic fungi in field.

Mineral Biofortification and Growth Stimulation of Lentil Plants Inoculated with Trichoderma Strains and Metabolites.

Biofortification of crops via agricultural interventions represents an excellent way to supply micronutrients in poor rural populations, who highly suffer from these deficiencies. Soil microbes can directly influence plant growth and productivity, e.g., by contrasting plant pathogens or facilitating micronutrient assimilation in harvested crop-food products. Among these microbial communities, Trichoderma fungi are well-known examples of plant symbionts widely used in agriculture as biofertilizers or biocontrol agents. In this work, eleven Trichoderma strains and/or their bioactive metabolites (BAMs) were applied to lentil plants to evaluate their effects on plant growth and mineral content in greenhouse or field experiments. Our results indicated that, depending upon the different combinations of fungal strain and/or BAM, the mode of treatment (seed and/or watering), as well as the supplementary watering with solutions of iron (Fe) and zinc (Zn), the mineral absorption was differentially affected in treated plants compared with the water controls. In greenhouse conditions, the largest increase in Fe and Zn contents occurred when the compounds were applied to the seeds and the strains (in particular, T. afroharzianum T22, T. harzianum TH1, and T. virens GV41) to the soil. In field experiments, Fe and Zn contents increased in plants treated with T. asperellum strain KV906 or the hydrophobin HYTLO1 compared with controls. Both selected fungal strains and BAMs applications improved seed germination and crop yield. This biotechnology may represent an important challenge for natural biofortification of crops, thus reducing the risk of nutrient deficiencies.

A novel Trichoderma asperellum strain DQ-1 promotes tomato growth and induces resistance to gray mold caused by Botrytis cinerea.

Gray mold caused by Botrytis cinerea is a major cause of economic losses during tomato production. In this study, we obtained 23 Trichoderma strains from tomato rhizosphere soil and their inhibitory effects on B. cinerea and the promoting effects on tomato growth were determined. Among them, the inhibition rate of strain DQ-1 on B. cinerea was 88.56%; compared with the control group, after treatment with strain DQ-1, the seeds germination rate and root length of tomato increased by 5.55 and 37.86%. The induced disease resistance of strain DQ-1 was evaluated by pot experiments. The disease incidence (DI) and disease severity index (DSI) of tomato pre-inoculated with strain DQ-1 and then inoculated with B. cinerea were reduced by 38 and 64% compared with the control. Furthermore, we detected the expression levels of tomato disease resistance related genes PR2 and TPX, ethylene pathway related genes ETR1 and CTR1 and jasmonic acid pathway related genes LOX1 and PAL in challenging and non-challenging inoculation treatments. The results showed that the tomato treated with strain DQ-1 triggered the system acquired resistance (SAR) and induced systemic resistance (ISR) pathway, thereby enhancing the disease resistance of tomato. Then the strain DQ-1 was identified as Trichoderma asperellum based on morphological characteristics and phylogenetic information. This study suggests that the novel T. asperellum strain DQ-1 can be a potential candidate for the biological control of gray mold in tomato.

Effect of Native Trichoderma asperellum Isolate on Phosphate Solubilization and Growth of Pea

Application of phosphorus solubilizing microbes is a promising tool for enhancing P uptake in plant. The aim of this study was to evaluate the phosphate solubilization potential and growth promotion of pea (Pisum sativum L.) by native Trichoderma asperellum isolate G3. Phosphate solubilization by T. asperellum strain was assessed in National Botanical Research Institute’s Phosphate (NBRIP) broth medium. Pea plants were inoculated by Trichoderma strain and grown in pot in phosphate deficit condition. The fungal strain was able to solubilize phosphate (from 188.95±2.04 to 262.50±3.80 mgL-1) in broth at different time periods and decreased solution pH. The Trichoderma inoculated pea plant increased the root growth, shoot growth, leaf number, shoot biomass, root biomass, total dry weight, chlorophyll a, chlorophyll b and carotenoid by 23.9%, 33.3%, 33%, 37.1%, 32.7%, 28.4%, 24.5%, 17.4% and 14.7% respectively over control after 5 weeks of post inoculation. The results showed that the native T. asperellum isolate G3 has great potential in the phosphorus solubilization. Ann. Bangladesh Agric. (2020) 24(2) : 121-124

Isolation and Selection of some Antagonizing Fungal Strains of Trichoderma And Chaetonium that can Inhibit the Growth of Pathogenic Fungi on Orange Trees

Decline disease has been discovered for a long time but infection is more extensively increasing. It is difficult to detect because the disease is originated from roots. Among the causes, soil fungi have been widely determined. Using fungicides is not an effective way to control the disease. In this case, biocontrol with suitable microbial strains is a potential approach. This study aims to investigate in vitro the possibility of using Trichoderma and Chaetonium to control the causing fungi. Two Chaetonium strains and 1 Trichoderma asperellum strain were isolated from diseased-root samples. Six strains of Trichoderma (isolated strains T1, T2, T3, T4, T5, T6) and three strains of Chaetonium (isolated strains C1, C2, C3) showed a reasonably antagonistic ability to Phytophthora, Fusarium, Rhizoctonia. Base on the PCR identification method, 6 strains of Trichoderma was isolated belonging to Trichoderma asperellum species, and 3 strains of Chaetonium belonging to 2 species Chaetomium globosum and Chaetomium cichlids.

Evaluation of the bioformulation of potent native strains of Trichoderma spp. against the foot rot/gummosis of Kinnow mandarin

BackgroundFoot rot/gummosis of citrus, caused by Phytophthora spp., is the most important disease of citrus, responsible for the yield losses of 10 to 30% in fruit production in major citrus growing countries. Considering the burden of disease, the present study was undertaken to evaluate different native potent strains of Trichoderma spp. against the foot rot/gummosis of citrus.ResultsBased on molecular characteristics, i.e., ITS ribosomal DNA sequence analysis, 3 isolates of Phytophthora nicotianae var. parasitica and 7 isolates of Trichoderma (6 isolates of T. asperellum and one of T. harzianum) were identified. Trichoderma isolates and Metalaxyl-M + Mancozeb were used to assess antagonistic activity against the foot rot/gummosis under field conditions. T. asperellum T20 mutant reduced gummosis lesion size (95.67%), improved feeder root density (0.0236 cm3), increased number (990.16), and yield of fruits (168.83 kg).ConclusionsThe talc-based bioformulation of T20 mutant (T. asperellum) strain, used as a soil treatment, was able to manage effectively the gummosis/foot rot of citrus and also exhibited the highest yield.

In Vitro Antagonistic Study of Maize Root Colonizing Fungal Isolates Against Fusarium moniliforme Causing Ear Rot Disease of Maize

In the present study, different root colonizing fungal isolates were isolated from the rhizospheric soil of maize growing areas of Uttar Dinajpur, West Bengal. All the isolates including test pathogen were identified from Indian Type Culture Collection, New Delhi. Plant growth promoting maize root colonizing fungal isolates- Penicillium pinophilum (ITC NO. 11,201.19), Trichoderma harzianum (ITC NO.11,203.19), Trichoderma asperellum (ITC NO. 11,209.19), Aspergillus niger (ITC NO. 11,204.19) and Penicillum purpurogenum (ITC NO. 11,207.19) exhibited antagonistic activities against F. moniliforme (ITC NO. 11,208.19) in vitro. Two antagonistic isolates of T. harzianum and eleven strains of T. asperellum showed antibiosis mechanism for antagonism against F. moniliforme with the range of Percent Inhibition of Radial Growth from 62.41% to 88.57%. Competitive mode of antagonism against test pathogen by the isolates of P. pinophilum, P. purpurogenum and six isolates of A. niger were found. Percent of inhibition of radial growth ranged from 57.14% to 91.42%. In our finding, antagonistic isolates especially Trichoderma harzianum (ITC NO. 11,203.19), Trichoderma asperellum (ITC NO. 11,209.19) strains either single or in combination with rest maize root colonizing strains could be used as potent growth promoters as well as biocontrol (BCA) agents.

Metarhizium robertsii in combination with Trichoderma asperellum reduce the malathion doses used to control ambrosia beetles: the case of Xyleborus affinis

ABSTRACT Invasive ambrosia beetles and their symbiotic fungi are responsible for destructive diseases like Laurel Wilt and Fusarium Dieback. Some biological treatments and chemical pesticides (e.g. malathion) have been proposed as alternatives to control these pests, however, to date there are no effective treatments. Here we evaluated the susceptibility of the ambrosia beetle Xyleborus affinis Eichhoff to the entomopathogenic fungus Metarhizium robertsii strain Xoch 8.1, and the efficacy of the mycopathogenic fungus Trichoderma asperellum strain Th-T4 (3) to inhibit the growth of the pathogenic ambrosia fungus Fusarium euwallaceae strain 744. Also, we compared the efficacy of a combination of M. robertsii Xoch 8.1 and T. asperellum Th-T4 (3) against X. affinis, and examined the feasibility of using this combination as an alternative to reduce the malathion doses that have been proposed to control ambrosia beetles. The treatment of X. affinis with M. robertsii (1 × 107 con/mL) alone or in combination with T. asperellum (1 × 106 con/mL) resulted in an average mortality of 76% (±7.5), which was statistically similar to that obtained with malathion at 600 ppm (96% ± 4.0). The combination of a lower concentration of malathion (60 ppm or 200 ppm) and both fungi was as efficient as malathion at 600 ppm. Mortality in negative controls (without fungal conidia or malathion) resulted in an average of 16% (±7.5). The proposed combined treatment reduces by up to one order of magnitude the required amount of malathion, and thus represents a potential alternative to control ambrosia beetle pests.

Assessment of Local Strain of Trichoderma asperellum Against Fusarium Spp

Trichoderma is unique fungus and now being most popular among the farmers as growth promoter and biocontrol agent. In present study local Trichoderma asperellum strain was evaluated against different Fusarium species in vitro and greenhouse conditions. In vitro study, Trichoderma asperellum was evaluated against 7 Fusarium species i.e., Fusarium oxysporum f. sp. ciceris, F. oxysporum f. sp. cubense (Tropical Race 1), F. oxysporum f. sp. cubense (Tropical Race 2), F. oxysporum f. sp. cubense (Tropical complex), F. oxysporum f. sp. lycopersici and Fusarium solani andpercentage reduction in the growth of these pathogens was ranged between 40.38 and 46.02%. This strainshowed strong antagonistic potential against F. oxysporum f. sp. lycopersici (73.91%)followed F. oxysporum f. sp. cubense race TR1 (64.49%), Fusarium udum (59.17),F. oxysporum f. sp. ciceris(58.33%), Fusarium solani(56.30%), F. oxysporum f. sp. cubenseTR 2(52.78%)and F. oxysporum f. sp. cubense TR (complex) 46.02%. In greenhouse study, Trichoderma asperellum was evaluated alongwith chitosan and botanicals against Fusarium oxysporum f. sp. lycopersici andminimum per cent disease index (PDI) was observed in treatment T4 (Seedling treatment with Trichoderma asperellum @ 5 g/lit + Chitosan @ 0.1% followed by its foliar spray) in which 44.66 per cent PDI recorded followed by T5 (Seedling treatment with Trichoderma isolate 8 @ 5 g/lit + Chitosan @0.1% followed by its foliar spray) in which 49.37 per cent PDI observed. The maximum per cent disease index was recorded in inoculated control (71.35%).