In vitro evaluation of the effect of aqueous extracts of Agave sisalana and Cymbopogon citratus on mycelial growth and conidia production of Pyricularia oryzae, causal agent of rice blast

The five different bio-agents viz., Trichoderma viride, T. harzianum, T. virens, Pseudomonas fluorescens and Bacillus subtilis were evaluated against Pyricularia oryzae at four and eight days after incubation through dual culture technique. Among the five different bio-agents, highest per cent inhibition of mycelial growth of fungus was recorded in T. virens i.e. 67 per cent and 70 percent after four and eight days after incubation respectively with mean of 68.5 per cent followed by Trichoderma viride with the inhibition of 61 and 63 per cent respectively with mean of 62 per cent. The Pseudomonas fluorescens did not show any inhibition of mycelial growth of P. oryzae as the pathogen over grew the bio-agents.

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Rice Blast in Puerto Rico

The Journal of Agriculture of the University of Puerto Rico ◽

10.46429/jaupr.v62i3.10367 ◽

1969 ◽

Vol 62 (3) ◽

pp. 290-300

Author(s):

Lii-Jang Liu

Keyword(s):

Puerto Rico ◽

Rice Straw ◽

Rice Blast ◽

Mycelial Growth ◽

Potato Dextrose Agar ◽

Pyricularia Oryzae ◽

In Vitro Tests ◽

Optimum Temperature ◽

Pathogenicity Tests

Rice blast, which had not been observed during the last six decades in Puerto Rico, reappeared recently in Manatí and in the Gurabo Substation, affecting Brazos, a cultivar introduced from Texas. Pathogenicity tests, as well as studies on the conidial morphology, showed that the fungus isolated from typical blast lesions is Pyricularia oryzae Cav. The physiology of the fungus and its sporulation on various media also were studied. The optimum temperature range, both for mycelial growth and for germination of conidia, was found to be between 24 to 28° C. Sporulation occurred satisfactorily on potato-dextrose agar enriched with coconut milk, and on steamed corn and barley, and rice-straw-decoction agars. In vitro tests with fungicides benomyl, pentachloronitrobenzene, mancozeb, chloroneb, and captan indicated that the first two compounds are the most effective in inhibiting mycelial growth of P. oryzae.

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AVALIAÇÃO DO REAL POTENCIAL INIBIDOR DE EXTRATOS ETANÓLICOS DE Ottonia martiana SOBRE Cylindrocladium spathulatum E Botrytis cinerea

FLORESTA ◽

10.5380/rf.v43i2.20199 ◽

2013 ◽

Vol 43 (2) ◽

pp. 225

Author(s):

Miriam Machado Cunico ◽

Celso Garcia Auer ◽

Marlon Wesley Machado Cunico ◽

Obdulio Gomes Miguel ◽

Patricio Peralta Zamora ◽

...

Keyword(s):

Factorial Design ◽

Botrytis Cinerea ◽

Mycelial Growth ◽

Black Spot ◽

Gray Mold ◽

Causal Agent ◽

In Vitro Testing ◽

Ethanolic Extracts ◽

Antifungal Potential

Extratos etanólicos de anestesia, Ottonia martiana Miq., foram reavaliados quanto à inibição do crescimento micelial dos fungos Cylindrocladium spathulatum (pinta-preta da erva-mate) e Botrytis cinerea (mofo-cinzento do eucalipto), por meio do planejamento fatorial. A ocorrência de decomposição de bioativos no processo de autoclavagem também foi investigada, por meio de teste de eficiência de extratos filtrados (filtro Millipore) e esterilizados (autoclave) no controle dos fitopatógenos, nas concentrações de 1, 10, 100 e 1000 ppm. Os extratos etanólicos filtrado e esterilizado inibiram o crescimento micelial dos fungos e foram mais ativos frente a B. cinerea.O extrato filtrado exibiu maior potencial antifúngico que o extrato esterilizado. O processo de esterilização por autoclavagem causou pequena decomposição dos bioativos presentes no extrato de anestesia.Palavras-chave: Anestesia; mofo-cinzento; pinta-preta. Abstract Fungitoxic potential of ethanolic extracts of anestesia in the control of phytopathogenic diseases. The antifungal potential of anestesia, Ottonia martiana Miq. was reassessed by factorial design, in vitro testing of fungal mycelial growth compared to the pathogenic isolates Cylindrocladium spathulatum, causal agent of black spot onyerba mate, and Botrytis cinerea causal agent of gray-mold on eucalypts. Occurrence of decomposition of bioactive of the autoclaving process was investigated using foliar detached test compared to the pathogens (1000 ppm). Ethanolic extracts - EBEtOH (filtered and autoclaved) inhibited the mycelial growth of C. spathulatum and B. cinerea (1000 ppm) and were more pronounced against B. cinerea (43.6 % and 68.9 %). EBEtOH filtered (0.22 µm) presented higher activity than EBEtOH autoclaved (C. spathulatum: 52.8 % and 43.6 %, B. cinerea: 68.9 % and 43.6 %), suggesting little decomposition ofbioactive after autoclaving. EBEtOH filtrate presented potential inhibition of 28 % in eucalypt leaves against B. cinerea. Keywords: Ottonia martiana; black spot; gray-mold.

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Conidia sporulation of Pyricularia oryzae in segments of wheat plants under six different temperatures

Ciência Rural ◽

10.1590/0103-8478cr20190573 ◽

2020 ◽

Vol 50 (4) ◽

Author(s):

Marcos Kovaleski ◽

João Leodato Nunes Maciel ◽

Gustavo Bilibio dos Santos ◽

Alieze Nascimento da Silva ◽

Carolina Cardoso Deuner

Keyword(s):

High Temperature ◽

Petri Dish ◽

Pyricularia Oryzae ◽

Causal Agent ◽

Temperature Conditions ◽

Wheat Blast ◽

Conidia Production ◽

Different Temperatures

ABSTRACT: Wheat blast is known for developing itself more intensely under relatively high temperature conditions but many aspects related to its epidemiology remain unknown. The objective of this research was to evaluate the sporulative capacity of Pyricularia oryzae Triticum (Pot), the causal agent of wheat blast, in tissues of wheat plants under different temperatures degrees. Wheat plants of the cultivar Anahuac 75, susceptible to blast, were inoculated in the stage of flowering with conidial suspensions (105 conidia/mL) of the Pot isolates Py 12.1.209 and Py 12.1.132. Seven days after the inoculation, plants were cut in the following segments: leaves, stems and rachis (with blast severity ranging from 40 to 60%). Groups of each one of the three plant segments with the lesions were disposed in Petri-dish moist chambers, that were submitted to six different temperature treatments (18, 21, 24, 27, 30 and 33 °C). The most appropriate model that related the conidia production with temperature was identified in the evaluations conducted with stems. The established equations allowed identifying that the highest production of conidia of Pot occurs between 24 and 27 °C.

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Identification of the Causal Agent of Leaf Spot of Betelnut and in vitro Evaluation of Fungicides and Plant Extracts Against it

Pakistan Journal of Biological Sciences ◽

10.3923/pjbs.2004.1758.1761 ◽

2004 ◽

Vol 7 (10) ◽

pp. 1758-1761 ◽

Cited By ~ 2

Author(s):

M.R. Islam . ◽

M.K. Hossain . ◽

M.H. Bahar . ◽

M.R. Ali .

Keyword(s):

Plant Extracts ◽

Leaf Spot ◽

Causal Agent ◽

In Vitro Evaluation

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Acid Rain Increases Impact of Rice Blast on Crop Health via Inhibition of Resistance Enzymes

Plants ◽

10.3390/plants9070881 ◽

2020 ◽

Vol 9 (7) ◽

pp. 881

Author(s):

Hong-Ru Li ◽

Hui-Min Xiang ◽

Jia-Wen Zhong ◽

Xiao-Qiao Ren ◽

Hui Wei ◽

...

Keyword(s):

Acid Rain ◽

Rice Blast ◽

Crop Yields ◽

Pyricularia Oryzae ◽

Plant Pathogen Interaction ◽

Rice Leaves ◽

Decreasing Ph ◽

Crop Health ◽

Cultivation Experiment

Worldwide, rice blast (Pyricularia oryzae) causes more rice crop loss than other diseases. Acid rain has reduced crop yields globally for nearly a century. However, the effects of acid rain on rice-Pyricularia oryzae systems are still far from fully understood. In this study, we conducted a lab cultivation experiment of P. oryzae under a series of acidity conditions as well as a glasshouse cultivation experiment of rice that was inoculated with P. oryzae either before (P. + SAR) or after (SAR + P.) simulated acid rain (SAR) at pH 5.0, 4.0, 3.0 and 2.0. Our results showed that the growth and pathogenicity of P. oryzae was significantly inhibited with decreasing pH treatments in vitro culture. The SAR + P. treatment with a pH of 4.0 was associated with the highest inhibition of P. oryzae expansion. However, regardless of the inoculation time, higher-acidity rain treatments showed a decreased inhibition of P. oryzae via disease-resistance related enzymes and metabolites in rice leaves, thus increasing disease index. The combined effects of high acidity and fungal inoculation were more serious than that of either alone. This study provides novel insights into the effects of acid rain on the plant–pathogen interaction and may also serve as a guide for evaluating disease control and crop health in the context of acid rain.

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