Control of white rot of garlic by antagonistic fungi under controlled environmental conditions

1984 ◽  
Vol 30 (7) ◽  
pp. 884-889 ◽  
Author(s):  
Vetúria L. de Oliveira ◽  
Margarida de M. Bellei ◽  
Arnaldo Chaer Borges
Keyword(s):  
Cell Wall ◽  
Trichoderma Harzianum ◽  
Environmental Conditions ◽  
Paecilomyces Lilacinus ◽  
White Rot ◽  
Infested Soil ◽  
Conidial Suspension ◽  
Sclerotium Cepivorum ◽  
Penicillium Sp

Several fungi were isolated from soil samples collected in areas with a high incidence of white rot disease of garlic at Amarantina county, Minas Gerais, Brazil. After the screening in vitro for antagonists to Sclerotium cepivorum, three fungi were found to be highly inhibitory to the pathogen. These fungi were identified as Trichoderma harzianum Rifai, Paecilomyces lilacinus (Thom.) Samson, and a Penicillium sp. The three antagonists produced in vitro nonvolatile antibiotics towards Sc. cepivorum. These substances were thermolabile (120 °C, 15 min) and significantly inhibited the growth of Sc. cepivorum. Interactions between the pathogen and each antagonist, studied by a dual slide-mount technique, showed that Pa. lilacinus and Penicillium sp. caused an inhibition halo to Sc. cepivorum although hyphal contact never occurred. Trichoderma harzianum showed inhibitory activity at a distance, and after contact with Sc. cepivorum, caused hyphal cytoplasm disintegration and cell wall collapse. This detrimental effect occurred either after direct penetration of the cell wall or after the formation of "coilings." The efficacy of the three antagonists in the biocontrol of white rot was tested under controlled environmental conditions in a nonsterilized, artificially infested soil (1 sclerotia per gram of soil). Trichoderma harzianum VL1 applied as a conidial suspension (106 conidia/mL) during the transplanting period significantly reduced the severity of white rot and increased the number of healthy plants when compared with the untreated control. Trichoderma harzianum gave significantly better protection to the plants than Coniothyrium minitans, a known biocontrol agent of sclerotia-forming fungi. Paecilomyces lilacinus, Penicillium sp., and the mixture of the three antagonists gave no protection against the disease.

scholarly journals Compatibility of the biocontrol agent Trichoderma harzianum C52 with selected fungicides

2001 ◽  
Vol 54 ◽  
pp. 84-88 ◽  
Author(s):  
K.L. McLean ◽  
J. Hunt ◽  
A. Stewart
Keyword(s):  
Disease Management ◽  
Trichoderma Harzianum ◽  
Seed Treatment ◽  
Biocontrol Agent ◽  
In Vitro Assay ◽  
Management Programme ◽  
White Rot ◽  
Vitro Assay ◽  
Sclerotium Cepivorum

Trichoderma harzianum C52 is an effective biocontrol agent of the onion white rot pathogen Sclerotium cepivorum For this biocontrol agent to be integrated into an existing disease management programme it must be compatible with the fungicides commonly used on onions The sensitivity of T harzianum spores to the field rate of eight fungicides commonly applied to onions was determined in an in vitro assay Results indicate that T harzianum was least sensitive to procymidone and captan and most sensitive to mancozeb tebuconazole and thiram A glasshouse pot trial confirmed that T harzianum was sensitive to mancozeb but tolerant of captan This research indicates that in furrow applications of T harzianum would be compatible with a captan and/or benomyl seed treatment for control of other seedling diseases

scholarly journals Avaliação da capacidade de produzir fitotoxinas in vitro por parte de fungos com propriedades antagônicas a nematóides

2006 ◽  
Vol 30 (6) ◽  
pp. 1230-1235
Author(s):  
Daniel Diego Costa Carvalho ◽  
Denilson Ferreira de Oliveira ◽  
Vicente Paulo Campos ◽  
Moacir Pasqual ◽  
Renato Mendes Gimarães ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Lactuca Sativa ◽  
Fusarium Moniliforme ◽  
Triticum Aestivum L ◽  
Paecilomyces Lilacinus ◽  
Penicillium Sp ◽  
Lactuca Sativa L

Em trabalho preliminar foram obtidos 24 isolados fúngicos com propriedades antagônicas a nematóides parasitas de plantas segundo experimentos realizados em laboratório. Para dar continuidade a tal trabalho, tornou-se desejável dispor de metodologia simples e de baixo custo para selecionar aqueles sem capacidade de produção de substâncias fitotóxicas, para serem empregados em experimentos em casa-de-vegetação com fitonematóides. Conseqüentemente, cultivaram-se os fungos em meio líquido e, após filtração, as fases líquidas foram liofilizadas e extraídas com acetato de etila/metanol. Os extratos foram concentrados sob vácuo e dissolvidos em água e solução de sacarose para serem submetidos a testes in vitro com sementes de alface (Lactuca sativa L.) e com coleóptilos de trigo (Triticum aestivum L.), respectivamente. Vinte e três isolados pertencentes aos gêneros Arthrobotrys, Aspergillus, Coniothyrium, Cunninghamella, Cylindrocarpon, Fusarium, Monacrosporium, Mortierella, Paecilomyces, Penicillium, Sclerotinia, Trichoderma e Verticillium, apresentaram atividade tóxica contra os coleóptilos de trigo. Apenas os isolados de Cylindrocarpon magnusianum (Sacc.) Wollenw., Fusarium moniliforme Shelden, Mortierella sp., Paecilomyces lilacinus (Thom.) Samson e Penicillium sp. apresentaram atividade fitotóxica no teste com sementes de alface. Somente um isolado de F. moniliforme se mostrou inativo em ambos os testes, o que sugere que não seja produtor de fitotoxinas.

scholarly journals Antagonism of the Two-Needle Pine Stem Rust Fungi Cronartium flaccidum and Peridermium pini by Cladosporium tenuissimum In Vitro and In Planta

2001 ◽  
Vol 91 (5) ◽  
pp. 457-468 ◽  
Author(s):  
Salvatore Moricca ◽  
Alessandro Ragazzi ◽  
Keith Richard Mitchelson ◽  
Gemma Assante
Keyword(s):  
Cell Wall ◽  
Spore Wall ◽  
Conidial Suspension ◽  
In Planta ◽  
Pine Seedlings ◽  
Host Cell Wall ◽  
Peridermium Pini ◽  
Hyphal Tip ◽  
Gain Access

Selected isolates of Cladosporium tenuissimum were tested for their ability to inhibit in vitro aeciospore germination of the two-needle pine stem rusts Cronartium flaccidum and Peridermium pini and to suppress disease development in planta. The antagonistic fungus displayed a number of disease-suppressive mechanisms. Aeciospore germination on water agar slides was reduced at 12, 18, and 24 h when a conidial suspension (1.5 × 107 conidia per ml) of the Cladosporium tenuissimum isolates was added. When the aeciospores were incubated in same-strength conidial suspensions for 1, 11, 21, and 31 days, viability was reduced at 20 and 4°C. Light and scanning electron microscopy showed that rust spores were directly parasitized by Cladosporium tenuissimum and that the antagonist had evolved several strategies to breach the spore wall and gain access to the underlying tissues. Penetration occurred with or without appressoria. The hyperparasite exerted a mechanical force to destroy the spore structures (spinules, cell wall) by direct contact, penetrated the aeciospores and subsequently proliferated within them. However, an enzymatic action could also be involved. This was shown by the dissolution of the host cell wall that comes in contact with the mycelium of the mycoparasite, by the lack of indentation in the host wall at the contact site, and by the minimal swelling at the infecting hyphal tip. Culture filtrates of the hyperparasite inhibited germination of rust propagules. A compound purified from the filtrates was characterized by chemical and spectroscopic analysis as cladosporol, a known β-1,3-glucan biosynthesis inhibitor. Conidia of Cladosporium tenuissimum reduced rust development on new infected pine seedlings over 2 years under greenhouse conditions. Because the fungus is an aggressive mycoparasite, produces fungicidal metabolites, and can survive and multiply in forest ecosystems without rusts, it seems a promising agent for the biological control of pine stem rusts in Europe.

Sclerotial morphogenesis in Sclerotium cepivorum in vitro

1992 ◽  
Vol 70 (4) ◽  
pp. 772-778 ◽  
Author(s):  
E. R. Littley ◽  
J. E. Rahe
Keyword(s):  
Potato Dextrose Agar ◽  
White Rot ◽  
Acellular Matrix ◽  
Sclerotium Cepivorum ◽  
Dry Conditions ◽  
Axenic Conditions ◽  
Survival Differences ◽  
Moisture Conditions ◽  
Scanning Electron

Sclerotial ontogeny, maturation, and aging in Sclerotium cepivorum are described using light and scanning electron microscopy. On potato dextrose agar, the mycelium spread, branching irregularly. Six days after inoculation sclerotial initials appeared, formed by hyphae branching and looping. From 6 to 8 days, the number and size of initials increased, and mucilagenous material appeared. By day 9, hyphal bundles formed in the mycelium. Between 9 and 11 days, spherical forms developed and the sclerotia grew. By day 12, an acellular matrix appeared, and to day 18 this matrix progressively obscured the surface hyphae and became black. A layer of ovoid rind cells developed at the surface. To examine the reduced survival of laboratory-produced compared with field-collected sclerotia, sclerotia from a variety of sources and conditions were compared. In general, the rind of sclerotia aged in dry conditions had a broken, irregular appearance versus fresh sclerotia or sclerotia aged under moist, axenic conditions. Sclerotia aged dry developed 1 to 4 layers of rind cells, while sclerotia kept moist developed only 1 or 2 layers. The structural and survival differences between laboratory-produced and natural sclerotia are attributable to differences in the moisture conditions under which they matured and aged. Key words: Sclerotium cepivorum, white rot, morphogenesis, sclerotia.

scholarly journals ACTIVIDAD ANTIMICÓTICA in vitro DE ERISOVINA

2009 ◽  
Vol 32 (4) ◽  
pp. 327-330
Author(s):  
Emmanuel Ibarra-Estrada ◽  
Rocío Téllez-Morales ◽  
Marcos Soto-Hernández ◽  
Mariano Martínez-Vázquez ◽  
Rosario García-Mateos ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Botrytis Cinerea ◽  
Trichoderma Harzianum ◽  
Alternaria Solani ◽  
Penicillium Sp

Varios alcaloides del género Erythrina presentan actividad farmacológica que parece estar asociada con la amina terciaria espiroamina. E. americana sintetiza erisovina, alcaloide tóxico con una D L50 de 25.23 mg kg-1 contra ratas ‘Winstar’, y que no ha sido probado como agente biocida contra microorganismos. En este estudio se investigó la actividad antimicótica de la erisovina, aislada de semillas maduras de E. americana en los hongos fitopatógenos Alternaria solani, Botrytis cinerea, Fusarium oxysporum, Monilia fructicola, Penicillium sp. y Trichoderma harzianum mediante el método de difusión de disco de papel. B. cinerea, F. oxysporum y M. fructicola presentaron la mayor susceptibilidad a la erisovina, ya que una dosis de 8 mg mL-1 inhibió el crecimiento del micelio en 88, 57 y 43 %, valores superiores al testigo tratado con dimetilsulfóxido. A. solani, Penicillium sp. y T. harzianum, tuvieron diámetros de inhibición apenas 27 % mayores que el testigo.

scholarly journals Effect of the mycoflora of ergot (Claviceps purpurea)sclerotia on their viability

2010 ◽  
Vol 46 (No. 2) ◽  
pp. 66-71 ◽  
Author(s):  
M. Ondřej ◽  
B. Cagaš ◽  
E. Ondráčková
Keyword(s):  
Trichoderma Harzianum ◽  
Fungal Species ◽  
In Vitro Tests ◽  
Conidial Suspension ◽  
Claviceps Purpurea ◽  
Clonostachys Rosea ◽  
Trichoderma Hamatum ◽  
Total Destruction ◽  
One Year

Twenty fungal species were isolated from sclerotia of ergot (Claviceps purpurea) originating from rye. In in vitro tests with the anamorphic stage of ergot (known as Sphacelia segetum) high mycoparasitic activity was exhibited only by two of them – Clonostachys rosea and Trichoderma harzianum, moderate mycoparasitic activity was detected in Ulocladium sp., Clonostachys catenulata, Trichoderma hamatum, and Trichothecium roseum. In in vitro tests of mycoparasitic activity with sclerotia of the fungus Sclerotinia sclerotiorum their rapid and total destruction was brought about only by the fungi Clonostachys rosea and Trichoderma harzianum. The viability of overwintering ergot sclerotia in the soil was influenced by their placement, age, depth of placement and treatment with a conidial suspension of the fungus Clonostachys rosea. The highest viability values were reported in fresh one-year-old sclerotia. In two-year-old sclerotia their viability was reduced and their sensitivity to microbial activity was higher. The sclerotia aged 3 years or more did not germinate and were all microbiologically degraded in the soil. More than 80% of degradation of sclerotia which were 1 to 2 years old was caused by the fungus Clonostachys rosea. The degradation of sclerotia aged 3 to 4 years was brought about by bacteria, soil edafauna (mites, nematodes) and fungi of the genera Trichoderma, Fusarium, Clonostachys, etc.

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