Antifungal activity of several medicinal plants extracts against the early blight pathogen (Alternaria solani)

The antifungal activity for several medicinal plants against the early blight fungus (Alternaria solani) has been investigated. These plants were Syrian marjoram (Majorana syriaca), rosemary (Rosmarinus officinalis), Greek sage (Salvia fruticosa), roselle (Hibiscus sabdariffa) and cotton lavender (Santolina chamaecyparissus). The inhibitory effect of these extracts on the radial mycelial growth as well as on spore germination was measured in vitro at various concentrations of crude extract (0.5 g dry plant powder/ml medium). Extracts of M. syriaca and H. sabdariffa were most effective causing total inhibition of mycelial growth and spore germination at 8–10% concentration. Extract of R. officinalis also caused total inhibition of the above two parameters but at double the concentration (20%). Extracts of S. fructicosa and S. chamaecyparissus produced relatively moderate antifungal activity. At 25% concentration, these extracts showed an incomplete inhibition in mycelial growth being around 75–85% and 70–90%, respectively. However, at this same concentration both plant extracts produced total inhibition of spore germination. Results of this study indicated that both extracts of M. syriaca and H. sabdariffa were strong inhibitors of this fungus and to levels comparable to standard fungicides. Further studies are required to determine the effect of these extracts in vivo to evaluate their potential as natural treatments for this disease.     

Polyamine metabolism during sclerotial development of Sclerotinia sclerotiorum

A study on polyamine metabolism and the consequences of polyamine biosynthesis inhibition on the development of Sclerotinia sclerotiorum sclerotia was conducted. Concentrations of the triamine spermidine and the tetramine spermine, as well as ornithine decarboxylase and S-adenosyl-methionine decarboxylase activities, decreased during sclerotia maturation. In turn, the concentration of the diamine putrescine was reduced at early stages of sclerotial development but it increased later on. This increment was not related to de novo biosynthesis, as demonstrated by the continuous decrease in ornithine decarboxylase activity. Alternatively, it could be explained by the release of putrescine from the conjugated polyamine pool. α-Difluoro-methylornithine and cyclohexylamine, which inhibit putrescine and spermidine biosynthesis, respectively, decreased mycelial growth, but did not reduce the number of sclerotia produced in vitro even though they disrupted polyamine metabolism during sclerotial development. It can be concluded that sclerotial development is less dependent on polyamine biosynthesis than mycelial growth, and that the increase of free putrescine is a typical feature of sclerotial development. The relationship between polyamine metabolism and sclerotial development, as well as the potential of polyamine biosynthesis inhibition as a strategy for the control of plant diseases caused by sclerotial fungi are discussed.     

Fungi isolated from Sclerotia ofSclerotium cepivorum and from soil and their effects upon the pathogen

Summary Data are presented on the antagonistic effects of the fungi isolated from sclerotia ofSclerotium cepivorum and from nonrhizosphere soil taken from around the roots of infected onions upon mycelial growth and sclerotial germination ofS. cepivorum. Most of the isolated fungi especiallyPenicillium species were antagonistic to mycelial growth. Sclerotial germination was slightly inhibited by diffusates of these fungal isolates. Testing the antifungal effect of someAllium extracts against the fungal isolates by the inhibition zone method showed that garlic extract has the greatest antifungal effects and onion extract is the least potent. However, spore germination tests indicated that onion extract completely inhibits the spore germination of all test fungi. The role of host-plant extracts in stimulating sclerotial germination is discussed.     

Deficiency of the melanin biosynthesis genes SCD1 and THR1 affects sclerotial development and vegetative growth,but not pathogenicity,in Sclerotinia sclerotiorum

The fungus Sclerotinia sclerotiorum is a necrotrophic plant pathogen causing significant damage on a broad range of crops. This fungus produces sclerotia that serve as the long‐term survival structures in the life cycle and the primary inoculum in the disease cycle. Melanin plays an important role in protecting mycelia and sclerotia from ultraviolet radiation and other adverse environmental conditions. In this study, two genes, SCD1 encoding a scytalone dehydratase and THR1 encoding a trihydroxynaphthalene reductase, were disrupted by target gene replacement, and their roles in mycelial growth, sclerotial development and fungal pathogenicity were investigated. Phylogenetic analyses indicated that the deduced amino acid sequences of SCD1 and THR1 were similar to the orthologues of Botrytis cinerea. Expression of SCD1 was at higher levels in sclerotia relative to mycelia. THR1 was expressed at similar levels in mycelia and sclerotia at early stages, but was up‐regulated in sclerotia at the maturation stage. Disruption of SCD1 or THR1 did not change the pathogenicity of the fungus, but resulted in slower radial growth, less biomass, wider angled hyphal branches, impaired sclerotial development and decreased resistance to ultraviolet light.     

The effect of polyamine biosynthesis inhibition on growth and differentiation of the phytopathogenic fungus Sclerotinia sclerotiorum

We studied the effects of several polyamine biosynthesis inhibitors on growth, differentiation, free polyamine levels and in vivo and in vitro activity of polyamine biosynthesis enzymes in Sclerotinia sclerotiorum. -Difluoromethylornithine (DFMO) and -difluoromethylarginine (DFMA) were potent inhibitors of mycelial growth. The effect of DFMO was due to inhibition of ornithine decarboxylase (ODC). No evidence for the existence of an arginine decarboxylase (ADC) pathway was found. The effect of DFMA was partly due to inhibition of ODC, presumably after its conversion into DFMO by mycelial arginase, as suggested by the high activity of this enzyme detected both in intact mycelium and mycelial extracts. In addition, toxic effects of DFMA on cellular processes other than polyamine metabolism might have occurred. Cyclohexylamine (CHA) slightly inhibited mycelial growth and caused an important decrease of free spermidine associated with a drastic increase of free putrescine concentration. Methylglyoxal bis-[guanyl hydrazone] (MGBG) had no effect on mycelial growth. Excepting MGBG, all the inhibitors strongly decreased sclerotial formation. Results demonstrate that sclerotial development is much more sensitive to polyamine biosynthesis inhibition than mycelial growth. Our results suggest that mycelial growth can be supported either by spermidine or putrescine, while spermidine (or the putrescine/spermidine ratio) is important for sclerotial formation to occur. Ascospore germination was completely insensitive to the inhibitors.     

Antifungal and enzymatic evaluation of plant crude extracts derived from cinnamon and rosemary against Sclerotinia carrot rot

The objective of this study was to assess the antifungal potential of plant crude extracts derived from cinnamon and rosemary against three isolates of Sclerotinia sclerotiorum under in vitro and in vivo conditions. The crude extracts were obtained using two different solvents including ethyl acetate (EA) and ethanol. The results showed that crude extracts of cinnamon are able to reduce mycelial growth of isolate 2 at volatile and contact phase by 35.4% and 78.2%, respectively. Furthermore, sclerotial myceliogenic at contact phase and carpogenic germination of isolate 2 were inhibited by 94.3% and 68.1%, respectively. In general, rosemary extracts showed less inhibitory efficacy than cinnamon. As the most effective treatment, EA extract of cinnamon was analysed using Gas Chromatography/Mass Spectrometry. The results showed the presence of 33 components and the major constituents were E‐cinnamaldehyde (66.4%) followed by Alpha‐Muurolene (4.86%), Alpha‐Copaene (4.73%) and 2H‐1‐Benzopyran‐2‐one (3.72%). The enzyme analysis showed that the activity of phenylalanine ammonia lyase, polyphenoloxidase and peroxidase decrease in the inoculated carrots after application of plant crude extracts indicating that they cannot be considered as resistance inducers against Sclerotinia carrot rot. In conclusion, cinnamon extract was found to be more effective against the pathogen. Although crude extracts of cinnamon and rosemary were able to reduce severity of carrot rot during storage, EA extract of cinnamon (2 g L^?1) was found to have practically significant effect against the disease.     

An atypical forkhead‐containing transcription factor SsFKH1 is involved in sclerotial formation and is essential for pathogenicity in Sclerotinia sclerotiorum

Sclerotinia sclerotiorum (Lib.) de Bary is a necrotrophic plant pathogen with a worldwide distribution. The sclerotia of S. sclerotiorum are pigmented multicellular structures formed from the aggregation of vegetative hyphae. These survival structures play a central role in the life and infection cycles of this pathogen. Here, we characterized an atypical forkhead (FKH)‐box‐containing protein, SsFKH1, involved in sclerotial development and virulence. To investigate the role of SsFkh1 in S. sclerotiorum, the partial sequence of SsFkh1 was cloned and RNA interference (RNAi)‐based gene silencing was employed to alter the expression of SsFkh1. RNA‐silenced mutants with significantly reduced SsFkh1 RNA levels exhibited slow hyphal growth and sclerotial developmental defects. In addition, the expression levels of a set of putative melanin biosynthesis‐related laccase genes and a polyketide synthase‐encoding gene were significantly down‐regulated in silenced strains. Disease assays demonstrated that pathogenicity in RNAi‐silenced strains was significantly compromised with the development of a smaller infection lesion on tomato leaves. Collectively, the results suggest that SsFkh1 is involved in hyphal growth, virulence and sclerotial formation in S. sclerotiorum.     

Biological control of Sclerotinia disease by Aspergillus sp. on oilseed rape in the field

Sclerotinia sclerotiorum causes serious yield losses to many crops worldwide. Aspergillus sp. Asp-4, previously shown to inhibit germination of sclerotia of S. sclerotiorum in vitro and in the field, was evaluated in field trials for suppression of this pathogen on oilseed rape. Spray application of Asp-4 to the soil prior to sowing rice in a rice–oilseed rape rotation resulted in a significant reduction in incidence of Sclerotinia stem rot on oilseed rape compared with the non-treated control in two field trials. This application of Asp-4 also resulted in a significant reduction in germination of sclerotia relative to the non-treated control in these field trials, suggesting that this reduction in sclerotial germination led to disease control. Microscopic examination demonstrated that Asp-4 could effectively colonise external and internal portions of sclerotia of S. sclerotiorum in vitro. Incubation of Asp-4 with sterile sclerotial material induced production of β-glucanase and chitinase activities by this isolate; β-glucanase and chitinase being potentially capable of degrading the glucan and chitin polymeric components of sclerotia. Incubation of Asp-4 with sterile sclerotial material also resulted in a significant reduction in dry weight of this sclerotial material relative to the non-treated control in 96?h in vitro experiments. Experiments reported here indicate that Aspergillus sp. Asp-4 has promise as a biological control agent for S. sclerotiorum on oilseed rape. Experiments reported here suggest that disease control results from inhibition of germination of sclerotial resting structures due to mycoparasitic colonisation by Asp-4.     

Individual and Combined Effects of Certain Pesticides on Rhizoctonia solani, Sheath Blight Pathogen of Rice

The effect of different pesticides (fungicide, herbicide and insecticide) on the mycelial growth and formation and germination of sclerotia of sheath blight pathogen of rice, Rhizoctonia solani Kühn was studied in nutrient medium and in natural soil. Among the herbicides and insecticides, fenitrothion (insecticide) and thiobencarb (herbicide) were the most effective in inhibiting the mycelial growth and sclerotial formation. These pesticides effected significant inhibition of both mycelialgrowth and sclerotial formation at 7.5 to 10μg/ml concentration while fungicides carbendazim and tolclofosmethyl effected almost complete inhibition at 2.5 μg/ml. Interestingly, a synergistic increase in the toxicity to mycelial growth, sclerotial formation and sclerotial germination was noticed when the fungicide, mancozeb and the herbicide, thiobencarb were applied at subtoxic concentration in combination. Such synergistic interactions between pesticides in a combination leading to increased toxicity suggest that under the current practice of applying fungicides, herbicides and insecticides either simultaneously or in rotation, certain combinations may help in reducing the dose of a fungicide in disease control.     

Aspergillus spp. eliminate Sclerotinia sclerotiorum by imbalancing the ambient oxalic acid concentration and parasitizing its sclerotia

Sclerotinia sclerotiorum, a pathogen of more than 600 host plants, secretes oxalic acid to regulate the ambient acidity and provide conducive environment for pathogenicity and reproduction. Few Aspergillus spp. were previously proposed as potential biocontrol agents for S. sclerotiorum as they deteriorate sclerotia and prevent pathogen's overwintering and initial infections. We studied the nature of physical and biochemical interactions between Aspergillus and Sclerotinia. Aspergillus species inhibited sclerotial germination as they colonized its rind layer. However, Aspergillus-infested sclerotia remain solid and viable for vegetative and carpogenic germination, indicating that Aspergillus infestation is superficial. Aspergillus spp. of section Nigri (Aspergillus japonicus and Aspergillus niger) were also capable of suppressing sclerotial formation by S. sclerotiorum on agar plates. Their culture filtrate contained high levels of oxalic, citric and glutaric acids comparing to the other Aspergillus spp. tested. Exogenous supplementation of oxalic acid altered growth and reproduction of S. sclerotiorum at low concentrations. Inhibitory concentrations of oxalic acid displayed lower pH values comparing to their parallel concentrations of other organic acids. Thus, S. sclerotiorum growth and reproduction are sensitive to the ambient oxalic acid fluctuations and the environmental acidity. Together, Aspergillus species parasitize colonies of Sclerotinia and prevent sclerotial formation through their acidic secretions.     

The importance of water potential range tolerance as a limiting factor on Trichoderma spp. biocontrol of Sclerotinia sclerotiorum

Biological control of fungal phytopathogens is often more variable in efficacy compared with disease suppression achieved by conventional pesticide use. Matching the environmental range of a potential biocontrol agent with that of the target phytopathogen is necessary if consistent disease suppression is to be achieved under field conditions. Strains of Trichoderma that could parasitise sclerotia of Sclerotinia sclerotiorum had their spore germination and mycelial growth (five strains) and ability to parasitise sclerotia (two strains) tested under a range of water potentials under laboratory conditions. Relative mycelial growth and germination of all strains decreased with decreasing osmotic and matric potentials, with matric potential having a greater impact on growth and germination over the range examined. Trichoderma harzianum LU698 mycelial growth was the least affected by decreasing osmotic potential than the other isolates, and Trichoderma atroviride LU141 growth least affected by decreasing matric potential. The germination of LU698 and LU144 was also generally less affected by decreasing osmotic potential, although generally decreasing matric potential had the greatest affect on the germination of LU698 along with T. atroviride LU132. Soil treatments of LU698 and Trichoderma asperellum LU697 reduced sclerotial viability in all but the lowest soil water potential tested, with LU698 being most effective at ?0.1 and ?0.3 MPa after 28 days and LU697 most effective at ?0.01 and ?1.5 MPa after 28 days. We conclude that differences in the tolerance of potential biocontrol agents to changing water potential is an important experimental factor to consider when assaying biocontrol or making predictions of biocontrol efficacy in the field.     

Volatiles from biofumigant plants have a direct effect on carpogenic germination of sclerotia and mycelial growth of <Emphasis Type="Italic">Sclerotinia sclerotiorum</Emphasis>

Aims

Sclerotia of Sclerotinia sclerotiorum survive in soil and germinate to produce apothecia which release airborne ascospores. Current control methods rely predominantly on the use of fungicides to kill ascospores. The aim of this research was to identify potential biofumigation treatments which suppress sclerotial germination, providing a potential alternative and long-term approach to disease management.

Methods

Microcosm and in vitro experiments were conducted using dried and milled plant material from six different biofumigant crop plants to determine effects on carpogenic germination of sclerotia and mycelial growth of S. sclerotiorum.

Results

All biofumigant plants significantly reduced germination of S. sclerotiorum sclerotia in the microcosm experiments, but were less effective against larger sclerotia. In vitro experiments showed a direct effect of biofumigant volatiles on both the mycelial growth of S. sclerotiorum, and carpogenic germination of sclerotia, where the most effective treatment was B. juncea ‘Vittasso’.

Conclusions

It was clear from this study that biofumigant crop plants have potential as part of an integrated disease management system for control of S. sclerotiorum. The microcosm experiments described here provide a straightforward and reliable screening method for evaluating different biofumigants for activity.

     

Increase in Endogenous and Exogenous Cyclic AMP Levels Inhibits Sclerotial Development in Sclerotinia sclerotiorum

Growth and development of a wild-type Sclerotinia sclerotiorum isolate were examined in the presence of various pharmacological compounds to investigate signal transduction pathways that influence the development of sclerotia. Compounds known to increase endogenous cyclic AMP (cAMP) levels in other organisms by inhibiting phosphodiesterase activity (caffeine and 3-isobutyl-1-methyl xanthine) or by activating adenylate cyclase (NaF) reduced or eliminated sclerotial development in S. sclerotiorum. Growth in the presence of 5 mM caffeine correlated with increased levels of endogenous cAMP in mycelia. In addition, incorporation of cAMP into the growth medium decreased or eliminated the production of sclerotia in a concentration-dependent manner and increased the accumulation of oxalic acid. Inhibition of sclerotial development was cAMP specific, as exogenous cyclic GMP, AMP, and ATP did not influence sclerotial development. Transfer of developing cultures to cAMP-containing medium at successive time points demonstrated that cAMP inhibits development prior to or during sclerotial initiation. Together, these results indicate that cAMP plays a role in the early transition between mycelial growth and sclerotial development.     

Determination of optimal carbon source and pH value for sclerotial formation of Polyporus umbellatus under artificial conditions

Polyporus umbellatus is one of the precious medicinal fungi, with sclerotia used as a diuretic agent and antidote in China for many years. This has led to the present interest in producing sclerotia of P. umbellatus in the laboratory due to a decreased abundance in natural sources. Here, we investigated the determining factors for sclerotial formation in P. umbellatus. Five carbon sources, namely, maltose, fructose, glucose, sucrose and soluble starch with different initial pH values were evaluated for their effects on mycelial growth and sclerotial development of P. umbellatus. Maltose, fructose and glucose could induce sclerotial formation of P. umbellatus. Sucrose and soluble starch could stimulate growth of the fungus but had no effect on sclerotial formation. The most efficient sclerotial production occurred with maltose followed by fructose and a pH of 5. In addition, different macroscopically evident characteristics of sclerotial development of P. umbellatus induced by different carbon sources were also observed. Our findings could provide new insights into further research on sclerotial production in P. umbellatus under artificial cultivation.     

Biochemical Investigations of Sclerotial Exudates of Sclerotium rolfsii and their Antifungal Activity

Exudates from sclerotia of two Sclerotium rolfsii isolates (one causing collar rot in Cicer arietinum, isolate VC971, and the other leaf spots in Rauvolfia serpentina, isolate VL016) were assayed for their antifungal activity against 26 fungi consisting of plant parasites as well as saprophytes. Spore germination of all the test fungi was affected by the exudates reaching 100% in some cases. Foliar spray with exudates of isolate VL016 significantly reduced disease incidence of balsam (Impatiens balsamina) powdery mildew caused by Erysiphe cichoracearum and pea (Pisum sativum) powdery mildew caused by Erysiphe pisi, under field conditions. Characterization of exudates from 25 isolates of S. rolfsii revealed pH ranging from 3.8 to 5.3 and colour from light yellow to deep yellow. Among the phenolic acids found in the exudates were tannic, gallic, caffeic, vanillic, ferulic, chlorogenic and cinnamic acids. Oxalic acid was also found in varied amounts. Among the phenolic acids, ferulic acid was found to be present at high concentration in exudates of most isolates (3.9–153.4 μg/ml). The antioxidant properties of phenolics, which generally inhibit fungal morphogenesis including spore germination along with the antifungal nature of some phenolics are chiefly attributed to the inhibitory effect of sclerotial exudates of S. rolfsii. Additionally, both the isolates VC971 and VL016 showed almost similar antifungal activities despite they are of different origin and thereby demonstrate the antifungal nature of sclerotial exudates.     

Effect of thiol redox state modulators on oxidative stress and sclerotial differentiation of the phytopathogenic fungus <Emphasis Type="Italic">Rhizoctonia solani</Emphasis>

This study showed that sclerotial differentiation in the filamentous phytopathogenic fungus Rhizoctonia solani is directly related to oxidative stress and thiol redox state (TRS). Sclerotial differentiation is modulated by the availability of non-cytotoxic −SH groups as was shown by the inhibition of sclerorial differentiation by the TRS modulator N-acetyl cysteine (AcCSH), and not necessarily with those of the TRS reduced components glutathione (GSH) and its precursor cysteine (CSH) as indicated by the GSH-biosynthesis inducer and inhibitor l-2–oxo-thiazolidine-4-carboxylate and l-buthionine-S,R-sulfoximine, respectively. Moreover, inhibition of sclerotial differentiation was accompanied by decrease of the high oxidative stress indicators, lipid peroxidation and DNA damage in the mycelial substrate where sclerotia initials are formed, which suggests that this phenomenon is related to oxidative stress as it is predicted by our theory on sclerotial differentiation.     

Morphological development of sclerotia by <Emphasis Type="Italic">Sclerotinia sclerotiorum</Emphasis>: a view from light and scanning electron microscopy

Sclerotinia sclerotiorum is a worldwide pathogen with a broad host spectrum pathogenic to around 400 plant species. Sclerotia formed by S. sclerotiorum serve as resting structures that secure fungal survival in soil for prolonged periods in the absence of a host plant or may help to overcoming periods of unsuitable growth conditions. In the present study, the morphological development of sclerotia was examined by light and scanning electron microscopy of fungal microcultures. Observations from microscopy indicated that, during the first 4 days of culture, the sclerotial primordial originate by dichotomous branching of apical hyphae and from the 5th day mycelial clusters were also observed, indicating the initiation stage of sclerotia formation. From the 6th to the 8th day, sclerotia turned from white to dark color, and water drops (exudates) were observed on their surface. The process of sclerotia formation ended at the 9th day when they were easy to detach from the culture medium and had a black coloration. All the morphological processes involved in the formation of sclerotia by S. sclerotiorum were observed with both light and scanning electron microscopy.     

THE EFFECT OF SOME PHYSIOLOGICAL AND ENVIRONMENTAL FACTORS ON SCLEROTIAL ASPERGILLI

Rudolph , Emanuel D. (Ohio State U., Columbus.) The effect of some physiological and environmental factors on sclerotial Aspergilli. Amer. Jour. Bot. 49(1): 71–78. Illus. 1962.—The effect of varying conditions of carbon-nitrogen balance, temperature, pH, and light upon the formation of sclerotia by 6 species of Aspergillus (A. alliaceus, A. avenaceus, A. flavus, A. quercinus, A. sclerotiorum and A. wentii) was studied. On Czapek's agar, optimal growth as well as maximum production of sclerotia and conidia took place at high sucrose and nitrate concentrations. In general, fewer sclerotia were formed with glucose than with sucrose, and very poor growth took place with lactose. Sclerotia were formed best at temperatures that were optimal or below optimal for mycelial growth. The ranges of pH through which sclerotia were formed were narrower than those through which conidia and mycelia were formed. Light had no effect upon sclerotium formation. The formation of sclerotia in A. alliaceus was found to represent the strand-type development. A number of UV-induced strains and a spontaneous mutant strain of A. alliaceus showing varying amounts of sclerotium and conidium production are characterized. It is suggested that the sclerotia in Aspergillus are sterile stromata.     

Oxidative Stress in Relation to Lipid Peroxidation, Sclerotial Development and Melanin Production by Sclerotium rolfsii

Melanin pigments constituted 13.9% of the chemical composition of the sclerotial walls of Sclerotium rolfsii and was associated with proteins, reducing sugars and amino acids. The lipid and ash contents in the sclerotial walls were double those in the hyphal walls of the fungus. Increasing age of the culture and maturation of the sclerotia were always accompanied by elevation of lipid peroxides and melanin pigments. Such behaviour may indicate that lipid peroxidation and melanin formation are operating in parallel during sclerotial biogenesis and maturation. These two processes depend on the theory of oxidative stress, as affected by growth conditions. Both processes could be stopped or sharply retarded when subjected to some antioxidant growth factors such as vitamins (ascorbic acid), micro-elements (selenium) and sulfhydryl compounds (glutathione). A clear relation between oxidative stress, myceliogenic germination and lytic activity via melanin production was observed. This finding appears promising in applying a new control measure against diseases caused by sclerotia-producing fungi without using traditional toxic fungicides.     

Trichoderma asperelloides antagonism to nine Sclerotinia sclerotiorum strains and biological control of white mold disease in soybean plants

Sclerotinia sclerotiorum is an important plant pathogen with worldwide distribution that causes severe economic losses of various agricultural crops such as soybean. This fungus is normally controlled with synthetic chemical fungicides that pose risks to the environment, and can be harmful to human health, and they can also induce resistance in pests. The aim of this study was to investigate the potential of Trichoderma asperelloides as a biocontrol agent towards white mold disease on soybeans crops. The antagonism of two strains of T. asperelloides (T25 and T42) isolated from soil samples was determined in-vitro by dual-culture confrontation testing on nine S. sclerotiorum strains obtained from sclerotia collected on diseased soybean plants. The mycelial growth and inhibition of carpogenic and ascospore germination by T. asperelloides extracts, as well as the efficacy of these on white mold control in soybeans were evaluated. Both strains of T. asperelloides exhibited high potential of antagonism. Methanolic and ethyl acetate extracts of the two T. asperelloides strains showed excellent growth inhibition (60–100%) on all of the pathogens tested. The ethyl acetate extracts of both T. asperelloides strains exhibited the highest efficacy against carpogenic germination, decreasing by 20–30% the number of ascospores per apothecium. Strains of T. asperelloides tested were more efficient in controlling white mold than two commercial products made from Trichoderma harzianum. The new strains of T. asperelloides have potential for successful biological control of white mold disease of soybean crops in the field.