RESUMO Objetivou-se com este trabalho avaliar o efeito de fosfito de potássio sobre o crescimento e a densidade micelial de Fusarium solani isolado de maracujazeiros. A verificação do efeito de fosfito de potássio sobre F. solani consistiu na diluição de 0, 1, 10, 50, 100, 250, 500, 750 e 1000 ppm do produto em BDA, com posterior avaliação do crescimento e da densidade micelial do fungo. A influência do pH do meio BDA, no crescimento de F. solani, foi testada pela diluição de ácido clorídrico no meio até a obtenção dos valores de pH idênticos àqueles das placas contendo as concentrações de fosfito de potássio. Após dez dias de incubação foi medido o crescimento do fungo. A mensuração da densidade micelial de F. solani foi realizada por meio da leitura de absorbância a 405 nm, de discos contendo micélio do fungo, em leitor de ELISA. O efeito fungicida ou fungistático de fosfito de potássio foi testado repicando-se o F. solani, proveniente das concentrações que o inibiu, para meio BDA puro e observando o seu posterior crescimento ou não. O fosfito de potássio inibiu o crescimento e a densidade micelial de F. solani, significativamente, a partir de 50 ppm. Não houve diferença significativa no crescimento de F. solani dentro da faixa de pH testada. O F. solani cresceu em meio BDA puro, após ser repicado do meio de cultura contendo as concentrações de fosfito de potássio que o inibiu, indicando ser um efeito fungistático do mesmo sobre o fungo.
RESUMOA antracnose, causada pelo fungo Colletotrichum gloeosporioides, é a doença de pós-colheita mais importante da passicultura. Este trabalho avaliou o potencial de Agaricus blazei e Lentinula edodes nas concentrações de 20, 40 e 60% (v/v) e do acibenzolar-S-metil (ASM) a 75 e 150 mg/L, aplicados isoladamente ou de forma combinada, na proteção de frutos de maracujá-azedo contra antracnose. Os frutos foram tratados (imersão, aspersão ou incorporados em cobertura de fécula de mandioca) e após 36h ou 72h, inoculados com o fungo. A avaliação da doença foi feita pela medida da área necrosada nos frutos aos 4, 8 e 12 dias após a inoculação (dai) nos ensaios I e II e aos 3, 6 e 9 dai nos ensaios III, IV e V. Aos quatro dias após a inoculação, o tratamento com A. blazei associado à fécula de mandioca 3% apresentou uma redução significativa da área necrosada comparado ao controle (p = 0,035). O L. edodes e ASM não reduziram a doença em nenhuma das concentrações e/ou épocas de avaliações realizadas. Quando os compostos foram aplicados de forma combinada nos frutos e estes não foram lavados antes da inoculação, houve uma redução significativa da área necrosada aos seis dias após a inoculação (p = 0,03). Entretanto, quando os frutos foram tratados, lavados e inoculados com o fungo não houve redução da doença em nenhuma das épocas avaliadas, mostrando que o modo de ação dos compostos utilizados, possivelmente, ocorre por um efeito protetor/residual atrelado a um efeito inibitório sobre C. gloeosporioides. Palavras-chave: Colletotrichum gloeosporioides, fécula de mandioca, pós-colheita, proteção. ABSTRACT Application of suspensions of Agaricus blazei, Lentinula edodes and acibenzolar-S-methyl for the reduction of anthracnose on passion fruitAnthracnose caused by Colletotrichum gloeosporioides is one of the most important diseases of passion fruit. This study evaluated the potential of Agaricus blazei and Lentinula edodes at concentrations of 20, 40 and 60% (v/v) and acibenzolar-S-methyl (ASM) at 75 and 150 mg/L, applied alone or in combination, for protecting passion fruit against anthracnose. The fruits were treated (immersion, sprayings or in coverage of cassava starch) and after 36h or 72h were inoculated with the fungus. Disease assessment was done by measuring the necrotic area in the fruits at 4, 8 and 12 dai (days after inoculation) in assays I and II and 3, 6 and 9 dai in assays III, IV and V. At three days after inoculation, the treatment with A. blazei associated with cassava starch 3% showed a significant reduction of necrotic area compared to the control (p = 0.035). The L. edodes and ASM treatments did not reduce the disease in any concentration and/or periods of the evaluations. When the compounds were applied in combination and the fruits were not washed before inoculation, there was a significant reduction of necrotic area six days after inoculation (p = 0.03). However, when fruits were treated, washed and inoculated with the fungus there was no reduction of disease in any of the periods evaluated, showing ...
Australian red cedar plants (Toona ciliata var. australis) grown in Piatã, in the region of Chapada Diamantina, Bahia State, Brazil, have been affected by a rot that attacks the plant root collar and roots. The symptoms begin in the plant basal region, causing darkened lesions which will later rot the bark and roots (Fig. 1A). These lesions will evolve to what is called trunk annealing which, in association with the root rot, may cause the plant death. Generalized leaf yellowing can be observed in the canopy, causing the leaves to dry. This disease occurs more frequently in the drier periods of the year and has caused the death of approximately 10 % of the planted area; as a consequence, it might render cedar cultivation unviable in that region.Root samples were collected and microscopic examinations revealed the presence of a whitish fungal mycelium containing conidiophores and long conidia, which were isolated in potato dextrose agar (PDA) culture medium and identified as belonging to the genus Cylindrocladium. To determine the species, small fragments of the PDA medium containing fungal structures were plated onto Petri dishes containing clove leaf-agar medium (CLA) and incubated for fifteen A B C D E
In January 2011, leaves of several daylily (Hemerocallis flava L.) plants in nurseries in Vitória da Conquista, northeastern Brazil, showed typical anthracnose symptoms. Reddish brown lesions with a yellow halo were first observed at the tip leaves. As the disease progressed, the lesions rapidly expanded down the leaves, resulting in severe blight. Small pieces up to 5 mm in diameter were removed from the lesion margins, surface sterilized for 1 min in 1.5% NaOCl, washed twice with sterile distilled water, and plated onto potato dextrose agar (PDA) amended with 0.5 g liter−1 streptomycin sulfate. Macroscopic colony characters and microscopic morphology characteristics of two isolates were developed after growth on PDA for 7 days at 25°C under a 12-h light/dark cycle. Colonies presented effuse mycelium, initially white and becoming pale gray, with numerous black structures like sclerotia, setae, and acervuli absent in culture media. Conidia were hyaline, aseptate, curved or slightly curved, round or somewhat acute apex, base truncate, 13.4 to 22.7 (18.2 ± 2.16) μm length, and 3.2 to 5.8 (4.24 ± 0.62) μm width, length/width ratio 4.37, and were typical of Colletotrichum spp. DNA sequencing of partial sequence of actin (ACT), chitin synthase (CHS-1), and glyceraldehyde-3-phosphate dehydrogenase (GPD) genes and the internal transcribed spacer (ITS1-5.8S-ITS2 rRNA gene cluster) were conducted to accurately identify the species. Sequences of two daylily isolates were highly similar to those of C. spaethianum (Allesch.) Damm, P.F. Cannon & Crous. A phylogenetic analysis using Bayesian inference and including published ACT, CHS-1, GPDH, and ITS data for C. spaethianum and other Colletotrichum species associated with daylily anthracnose (1,3) showed that the isolated fungi belong to the C. spaethianum clade. Sequences of the isolates obtained in this study were deposited in GenBank (ACT Accession Nos. KC598114 and KC598115; CHS-1 Accession Nos. KC598116 and KC598117; GPDH Accession Nos. KC598118 and KC598119; ITS Accession Nos. KC598120 and KC598121). Cultures are deposited in the Culture Collection of Phytopathogenic Fungi of the Universidade Federal Rural de Pernambuco, Recife, Brazil (CMM1224 and CMM1225). Pathogenicity tests were conducted with the two C. spaethianum strains on daylily leaves. Mycelial plugs taken from the margin of actively growing colonies (PDA) of each isolate were applied in shallow wounds near the tip leaves. Four detached leaves were inoculated for each isolate, and PDA discs without fungal growth were used as controls. The leaves were maintained in humid chamber for 2 days at 25°C under a 12-h photoperiod. Anthracnose symptoms that closely resembled those observed in the affected nurseries were developed up to 5 days after inoculation. No symptoms developed on the control plants. C. spaethianum was successfully re-isolated from symptomatic plants to fulfill Koch's postulates. C. spaethianum was described from H. fulva and H. citrina in China, Hosta sielbodiana in Germany, and Lilium sp. in South Korea (3), and from Peucedanum praeruptorum in China (2). To our knowledge, this is the first report of C. spaethianum in Brazil and the first report on H. flava. References: (1) U. Damm et al. Fungal Divers. 39:45, 2009. (2) M. Guo et al. Plant Dis. 97:1380, 2013. (3) Y. Yang et al. Trop. Plant Pathol. 37:165, 2012.
This study aimed to evaluate the inclusion of castor bean meal in the diet for lactating cows on Bracharia brizhanta pasture and its implications for nutritional and productive parameters. Eight crossbred cows were distributed in two 4 x 4 Latin squares, with four (0%; 3.33%; 6.66% and 10%) inclusion levels of castor bean meal in the total diet. The experiment consisted of four experimental periods of 21 days each. The digestibility and dry matter intake were estimated from fecal output, checked with the aid of external (chromium oxide) and internal (iNDF) indicators. Urine and milk were collected to determine the nitrogen balance and microbial protein production. The inclusion of different levels of castor bean meal in the diet for lactating cows did not affect the intake of dry matter and nutrients, and the same lack of effect was found for the digestibility of dry matter and total digestible nutrients, variation in body weight, milk production, chemical composition of milk, microbial production and nitrogen balance. The inclusion of up to 10% castor bean meal in the total diet did not influence productive parameters evaluated, and the use was conditioned to the price of castor bean meal. Key words: Nitrogen balance. Consumption. Milk production. Microbial protein. ResumoObjetivou-se avaliar a inclusão de farelo de mamona na alimentação de vacas lactantes em pastejo de Bracharia brizhanta e suas implicações nos parâmetros nutricionais e produtivos. Foram utilizadas oito vacas mestiças distribuídas em dois quadrados latinos 4 x 4, com quatro níveis de inclusão de farelo de mamona na ração total; 0%; 3,33%; 6,66% e 10%. O experimento foi constituído de quatro períodos experimentais, com duração de 21 dias cada. A digestibilidade e o consumo de matéria seca foram estimados a partir da produção fecal, verificada com o auxílio de indicadores externo (oxido de cromo) e interno (FDNi). Foi feita a coleta de urina e leite para determinação do balanço de nitrogênio
In October 2020, sooty moulds were found covering the leaves of neem trees (Azadirachta indica) in Vitória da Conquista, Bahia, Brazil. Sooty moulds usually grow on honeydew secreted by insects. However, in this observation, insects were not visible on the sooty mould‐infected plants. Rather, the sooty mould grew on the host secretions. Inoculation was performed to confirm the ability of the fungus to grow on host nectaries. Based on the morphological features and phylogenetic analysis, Capnodium alfenasii was identified as the sooty mould agent. To our knowledge, this is the first report on the occurrence of this fungus on neem plants.
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