A chromista, possible Pythium aphanidermatum, was isolated from severely damage seeds and seedlings recently started from Jatropha curcas L. non toxic seeds sown in the tropical area of Veracruz, ...Mexico. In order to study pathogenic Pythium aphanidermatum effects over pre-emergent and post-emergent stages, seeds and young seedlings were inoculated with the isolated pathogen, and the chromista showed possible pathogenic activity against pre-emergency and recently started post-emergency; however, statistically significant damaged was not found in older seedlings.  Â
Endophytic fungi have been reported to have mutual symbiosis with their host. This research aimed to obtain nonpathogenic isolates of endophytic fungi from roots, stems, and branches of chili pepper. ...Endophytic fungi were isolated on 10% malt extract agar (MEA) after serial surface sterilization of plant parts. The effect of endophytic fungi on the development of chili pepper seeds were tested by growing seeds on media containing endophytic fungi isolate. As many as 138 isolates of endophytic fungi were successfully isolated from chili pepper plants from Garut and Bogor. Based on colony morphology the isolates can be differentiated into 9 morphotypes. Among the total isolates, 13.04% are nonpathogenic. Some of them (7,25%) do not effect seedling significantly compared to control and some isolates (5.79%) caused better seedling growth than control. Endophytic fungi having the potential to promote plant growth was identified as Aspergillus sp., Fusarium sp., Penicillium sp., sterile hyphae 1, 2, and 3.
A series of cultural, morphological and patogenic characters were evaluated in 8 isolated of Sclerotium rolfsii Sacc. coming from bean and sunflower. Variability exists among them in the Rate of ...Micelial Growth, number and diameter of formed esclerocios, density of micelium, rizomorphes presence, duration of esclerotium formation process and patogenicity on beans and sunflower. These differences, united to the presence of incompatibility and antagonism among the isolated allow us to discern presence of different races of pathogen.
A virulência de isolados dos fungos entomopatogênicos Beauveria bassiana, Metarhizium anisopliae e Paecilomyces fumosoroseus foi avaliada sobre Oligonychus yothersi (McGregor) em laboratório. Os ...bioensaios de seleção e de determinação de CL50 e TL50 foram realizados com discos foliares de erva-mate previamente infestados com 10 fêmeas adultas do ácaro. Para cada isolado um conjunto de cinco discos foram pulverizado com 1 ml da suspensão padronizada em 1,0x10(7) conídios/ml (50 ácaros por tratamento). Após pulverizados os discos foram mantidos flutuando em água destilada em caixas plásticas (3 cm diâmetro e 1,5 cm altura), em câmara tipo B.O.D. (temperatura: 25 ± 1ºC; UR: 70 ± 10% e fotofase de 12h). A mortalidade total foi avaliada cinco dias após a inoculação. Os ácaros mortos foram transferidos para câmara úmida para confirmação de mortalidade, sendo examinados sob microscópio ocular seis dias após a morte. O fungo B. bassiana apresentou grande potencial como agente de controle microbiano, podendo ser incorporado em programas de manejo integrado do ácaro vermelho da erva-mate, O. yothersi. Os isolados de B. bassiana UEL02, UEL08, UEL10, UEL50, CG082, CG166, CG375, CG424 e CG481 foram os mais virulentos. Eles apresentaram mortalidades corrigida e confirmada superiores a 70% e valores estimados de CL50 variando entre 1,9x10(6) e 6,0x10(7) conídios/ml e de TL50 variando entre 3,3 e 4,3 dias.
The virulence of strains of the entomopathogenic fungi Beauveria bassiana, Metarhizium anisopliae and Paecilomyces fumosoroseus was evaluated on Oligonychus yothersi (McGregor) in laboratory. The bioassays for strain selection and determination of LD50 and LT50 were elaborated with leaf disks of Paraguay tea infested with 10 adult females of the mite. Groups of five disks were sprayed with 1 ml of the suspension standardized in 1.0x10(7) conidia per ml (50 mites per treatment) of each strain. After that, the disks were maintained floating in distilled water in plastic boxes (3 cm diameter and 1.5 cm height), in environmental chamber (temperature: 25 ± 1ºC; RH: 71 ± 10% and 12h photophase). Five days after the inoculation the total mortality was evaluated, and the dead mites were transferred to humid chamber. Six days after death, the sporulation in the cadavers was examined under an optical microscope. B. bassiana presented great potential as a microbial control agent, and can be incorporated in integrated pest management of the Paraguay tea red mite, O. yothersi. The B. bassiana strains UEL02, UEL08, UEL10, UEL50, CG082, CG166, CG375, CG424 and CG481, were the most virulent, with corrected and confirmed mortality higher than 70% and estimated value of CL50 varying between 1.9x10(6) and 6.0x10(7) conidia per ml and TL50 varying between 3.3 and 4.3 days.
O presente trabalho foi conduzido com a finalidade de avaliar a virulência de conídios de três linhagens do fungo Nomuraea rileyi produzidos em arroz, sorgo e soja estocados por 3 meses a 4°C. ...Verificou-se que conídios armazenados apresentaram baixas taxas de mortalidade de Anticarsia gemmatalis.The present work was carried out aiming to estimate the conidia virulence of three strains of Nomuraea rileyi fungi. Conidia produced in rice, sorghum and soybean was stored at 4°C for three months. It was observed that stored conidia caused the Anticarsia gemmatalis death rate reduction.
Phoma sp. (sect. Peyronellaea), como agente etiológico de mancha foliar de Paspalum atratum no Brasil Anjos, José R. N.(Empresa Brasileira de Pesquisa Agropecuária Centro de Pesquisa Agropecuária dos Cerrados); Charchar, Maria J. A.(Empresa Brasileira de Pesquisa Agropecuária Centro de Pesquisa Agropecuária dos Cerrados); Anjos, Sérgio S. N.(Universidade de Brasília Faculdade de Ciências da Saúde, Ciências Farmacêuticas) ...
Fitopatologia brasileira,
02/2005, Volume:
30, Issue:
1
Journal Article
Open access
Phoma sp. (sect. Peyronellaea) foi consistentemente isolado de plantas de Paspalum atratum cv. Pojuca (capim Pojuca) com sintomas de manchas foliares em uma população no Distrito Federal, em 2002. Os ...conídios mostraram-se hialinos, predominantemente elípticos, unicelulares, gutulados, medindo entre 2,50-5,25 mim de largura e 10,25-17,25 mim de comprimento. Os picnídios mostraram-se escuros, medindo entre 100-310 mim de diâmetro, com pescoço curto, na maioria são globosos e solitários. Clamidósporos multicelulares, freqüentemente semelhantes a conídios de Alternaria foram observados nas colônias. Testes de patogenicidade em casa de vegetação e o ubsequente reisolamento do fungo confirmaram a hipótese de que Phoma sp. é o agente etiológico das manchas foliares de capim Pojuca. Os primeiros sintomas apareceram em todas as plântulas inoculadas, quatro a cinco dias após a inoculação. Sete outras espécies de gramíneas foram suscetíveis ao fungo. A ocorrência de manchas foliares de capim Pojuca causadas por Phoma sp. é relatada pela primeira vez no Brasil.
The fungus Phoma sp. (sect. Peyronellaea) was consistently isolated from infected Paspalum atratum cv. Pojuca (Pojuca grass) plants with leaf spot symptoms in the Federal District, Brazil, in 2002. Conidia were hyaline, usually ellyptical, unicellular, gutullate, 2,50-5,25 x 10,25-17,25 mum. Pycnidia were mostly solitary, 100-310 mum diameter, globose, usually with a short neck. Multicellular chlamidospores often resembling conidia of Alternaria were present in the colonies. Pathogenicity tests under greenhouse conditions and subsequent reisolations of Phoma sp. from artificially inoculated Pojuca seedlings confirmed the hypothesis that this fungus was the causal agent of the disease. Symptoms of leaf spot appeared four to five days after inoculation in 100% of the inoculated Pojuca grass plants. All seven species of grasses evaluated were susceptible to this fungus. The occurrence of leaf spots of Pojuca grass caused by Phoma sp. is reported for the first time in Brazil.
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