scholarly journals Extratos vegetais do gênero capsicum com potencial atividade antifúngica contra Rhizoctonia solani e Sclerotium rolfsii

2020 ◽  
Vol 11 (1) ◽  
pp. 89-98
Author(s):  
Aline Souza da Fonseca ◽  
Cléberson De Freitas Fernandes ◽  
José Roberto Vieira Júnior ◽  
Rodrigo Barros Rocha ◽  
Tamiris Chaves Freire ◽  
...  
Keyword(s):  
Rhizoctonia Solani ◽  
Capsicum Annuum ◽  
Sclerotium Rolfsii ◽  
Capsicum Frutescens ◽  
Capsicum Baccatum

O uso excessivo de fungicidas na agricultura tem sido bastante questionado pela sociedade em geral em função destes serem caros, de elevada persistência no solo e de elevado risco à saúde humana e ao meio ambiente. Nesse sentido medidas alternativas de controle tem sido buscadas. O presente estudo teve como objetivo avaliar a eficiência de diferentes extratos de sementes de pimentas do gênero Capsicum sobre o crescimento micelial de Rhizoctonia solani e Sclerotium rolfsii. O delineamento experimental foi o inteiramente casualizado com 25 tratamentos, tendo dois controles (água e fungicida) e quatro repetições para os testes in vitro e seis para in vivo. Os dados foram submetidos à análise de Scott Knott a 5% de probabilidade. Os testes in vitro evidenciaram que todos os extratos se mostraram eficientes na inibição dos patógenos, destacando-se os extratos de Capsicum annuum, os quais obtiveram resultados significativamente superiores ao controle com o fungicida.  Nos ensaios em diluição seriada, observou-se que na concentração de até 1x105 os extratos foram capazes de inibir o patógeno S. rolfsii. No ensaio in vivo em folhas destacadas, 13 extratos apresentaram eficiência no controle da mela, sendo que os extratos obtidos a partir de Capsicum baccatum e Capsicum frutescens apresentaram efeitos de controle semelhantes ao fungicida.  

Effect of the herbicide Pyradur on host cell wall degradation by the sugarbeet pathogens Rhizoctonia solani and Sclerotium rolfsii

1996 ◽  
Vol 74 (9) ◽  
pp. 1407-1415 ◽  
Author(s):  
Mohamed S. El-Abyad ◽  
Amira M. Abu-Taleb ◽  
Tarek Abdel-Mawgood
Keyword(s):  
Cell Wall ◽  
Rhizoctonia Solani ◽  
Sclerotium Rolfsii ◽  
Pectate Lyase ◽  
Inoculum Potential ◽  
Cell Wall Degrading Enzymes ◽  
Degrading Enzymes ◽  
Alkaline Conditions

Pyradur applied to soil at 0.6–2.4 µg∙g−1 active ingredients suppressed infection of three sugarbeet cultivars by Rhizoctonia solani and Sclerotium rolfsii. In the absence of Pyradur, R. solani was more virulent than S. rolfsii against 'Raspoly' and 'TOP', whereas S. rolfsii was more virulent than R. solani against ‘Tribel’. Virulence was directly correlated with the activities of cell wall degrading enzymes produced by mese pathogens in vivo and on cell walls in vitro. Reduced virulence of R. solani and S. rolfsii under Pyradur stress was due to decreased inoculum potential of the two pathogens at the utilized concentrations of herbicide in situ and to reduced production of cell wall degrading enzymes in vitro and in host tissues. In addition, shifts in the pH of cell wall amended media, because of changes in the nature of metabolic products of the pathogens under Pyradur stress, suggest possible repression or stimulation of the activity of the enzymes involved in degradation in vivo, of which cellulase and polygalacturonase are favoured by acid conditions, and galactanase, mannase, and pectate lyase are favoured by alkaline conditions. Keywords: sugarbeet, Rhizoctonia solani, Sclerotium rolfsii, Pyradur, metolachlor, chloridazon, growth activities, pathogenicity, virulence, cell wall enzymes.

scholarly journals Anastomosis grouping of Rhizoctonia solani and binucleate Rhizoctonia spp. isolated from pepper in Erzincan, Turkey

2013 ◽  
Vol 49 (No. 3) ◽  
pp. 127-131 ◽  
Author(s):  
S. Tuncer ◽  
C. Eken
Keyword(s):  
Rhizoctonia Solani ◽  
Capsicum Annuum ◽  
Binucleate Rhizoctonia ◽  
Anastomosis Groups ◽  
Capsicum Annuum L

Ninety eight isolates of Rhizoctonia spp. were obtained from roots of pepper (Capsicum annuum L.) grown in Erzincan, Turkey during the period 2007–2008. The most prevalent multinucleate anastomosis groups (AG) were AG-4 (85.2%), followed by AG-2 type 1 (7.4%), AG-6 (5.0%), and AG-3 (2.5%). The population of binucleate Rhizoctonia spp. comprised AG-A (82.4%), AG-K (11.8%), and AG-G (5.9%). Rhizoctonia solani AG-3 and AG-6, as well as binucleate Rhizoctonia spp. AG-G and AG-K on pepper (C. annuum) were firstly determined in this study. During both in vitro and in vivo pathogenicity experiments differences in virulence level between R. solani and binucleate Rhizoctonia spp. isolates were observed. Isolates of R. solani AG-2 type 1 and AG-4 were the most virulent, binucleate Rhizoctonia spp. isolates of AG-A were less virulent, whereas binucleate Rhizoctonia spp. isolates of AG-G and AG-K were non-pathogenic.  

scholarly journals Potencial de controle de espécies de Piper sobre fungos fitopatogênicos

2019 ◽  
Vol 9 (8) ◽  
pp. 260-272
Author(s):  
Jessica Silva Felix Bastos ◽  
Cléberson De Freitas Fernandes ◽  
José Roberto Vieira Junior ◽  
Aline Souza Fonseca ◽  
Tamiris Chaves Freire ◽  
...  
Keyword(s):  
Phaseolus Vulgaris ◽  
Rhizoctonia Solani ◽  
Sclerotium Rolfsii

A produção de feijoeiro comum (Phaseolus vulgaris) é limitada, dentre outros fatores, pela ocorrência de doenças, destacando-se a mela do feijoeiro e o mofo cinzento, causados pelos fungos Rhizoctonia solani e Sclerotium rolfsii, respectivamente. Extratos vegetais com potencial fungicida se destacam como um método alternativo no controle de fitopatógenos. O objetivo deste trabalho foi avaliar extratos de espécies do gênero Piper no crescimento micelial dos fungos R. solani e S. rolfsii. Foram preparados extratos aquosos e alcoólicos nas proporções de 1:10, 1:100, 1:1000 e 1:10000mg/mL, obtidos a partir de materiais secos e frescos de folhas, talos e inflorescências de P. carniconnectivum, P. hispidum, P. nigrum, P. permucronatum, P. tuberculatum e P. umbellatum, cultivadas em casa de vegetação e campo, totalizando cento e um tratamentos. A atividade antifúngica foi avaliada pelo método de difusão em poços, utilizando meio BDA. Alíquotas de 10µL dos extratos avaliados foram depositadas em cada poço, e um disco de micélio de 0,5cm de diâmetro do patógeno desafiante adicionado no centro da placa. Os halos de inibição formados foram medidos a cada 24h, no sentido longitudinal e transversal. Testes in vivo foram conduzidos em folhas destacadas e em plântulas de feijoeiro. Folhas destacadas de feijoeiro foram acondicionadas em caixas tipo Gerbox, e mudas de feijoeiro mantidas em câmara úmida. Sobre as folhas foram pulverizados os extratos avaliados, e após 24h, uma suspensão de micélio do patógeno R. solani, na concentração de 1x106 fragmentos de micélio.mL-1 também foi pulverizada, avaliando-se a cada 24h a severidade da doença. O delineamento experimental dos testes in vitro e in vivo foi o inteiramente casualizado, com três testemunhas. Dentre os extratos testados in vitro, vinte e seis demonstraram potencial inibitório no controle de R. solani na maior concentração, e doze mantiveram-se eficientes até a concentração 1:100, destacando-se os extratos obtidos das espécies P. permucronatum e P. carniconnectivum. Nos ensaios com o fungo S. rolfsii, dez extratos mostraram eficiência na inibição do patógeno, destacando-se o extrato aquoso de P. tuberculatum na maior concentração. No ensaio in vivo com folhas destacadas dez extratos apresentaram eficiência no controle da mela do feijoeiro, sendo que os extratos obtidos a partir de P. permucronatum, P. carniconnectivum e P. nigrum apresentaram efeitos de controle semelhantes ao controle fungicida, permanecendo extratos de P. permucronatum eficientes em testes in vivo com mudas de feijão em câmara úmida. Os resultados obtidos sugerem que os extratos de espécies do gênero Piper podem vir a ser utilizados futuramente como fonte de novas moléculas bioativas, visando o controle destes patógenos.

Fungicides to control fungal competitors in Chinese straw mushroom

1969 ◽  
Vol 71 (2) ◽  
pp. 165-176
Author(s):  
Lydia I. Rivera-Vargas ◽  
Paul R. Hepperly
Keyword(s):  
Sugarcane Bagasse ◽  
Radial Growth ◽  
Sclerotium Rolfsii ◽  
Growth Reduction ◽  
Coffee Pulp ◽  
Perceived Importance ◽  
Straw Mushroom ◽  
Visible Growth

Laboratory and production bed observations reveal that the major fungal competitors of the Chinese straw mushroom growing on sugarcane bagasse are Sclerotium rolfsii Sacc., Corticium sp., Coprinus sp., Aspergillus flavus Link ex Fries and Chaetomium globosum Kunze ex Steud. Because of their perceived importance, these five fungi were selected for control studies. The selectivity of fungicides for the control of these fungi in Chinese straw mushroom beds was tested in vitro. Benomyl, captan, carboxin, chloroneb, mancozeb and penthachloronitrobenzene (PCNB) were tested in poison agar tests at the rates of 1, 10 and 100 p/m a.i. with Chinese straw mushroom and the selective competitors. Mushroom radial growth was reduced in all treatments of carboxin and at 10 and 100 p/m of chloroneb. Compared to these, PCNB was intermediately toxic. Chinese straw mushroom was tolerant to all concentrations of benomyl, captan and mancozeb. A. flavus radial growth was highly reduced with benomyl and slightly reduced by carboxin, chloroneb and PCNB. S. rolfsii showed growth reduction at 10 and 100 p/m of PCNB, chloroneb and carboxin. Growth of Coprinus sp., Corticium sp., C. globosum and A. flavus was reduced over 90% with treatments of benomyl at 100 p/m. Fungicidal sprays were evaluated in vivo on sugarcane bagasse and coffee pulp beds. Poor pasteurization of the coffee pulp was associated with rampant development of Aspergillus fumigatus Fries. and Mucor sp. Partial superficial control of these fungi was obtained with mancozeb alone (50 to 75% reduction of visible growth). Benomyl alone and in combination with mancozeb gave excellent suppression of fungi on the mushroom beds (90% reduction of visible growth). None of the treatments controlled fungi within the beds.

Biocontrol activity of Azospirillum brasilense Sp245 against Rhizoctonia solani by in vitro/in vivo tests, DGGE analysis

2010 ◽  
Vol 150 ◽  
pp. 503-503 ◽  
Author(s):  
L. Vettori ◽  
C. Felici ◽  
A. Russo ◽  
S. Morini ◽  
S. Cummings ◽  
...  
Keyword(s):  
Rhizoctonia Solani ◽  
Azospirillum Brasilense ◽  
Dgge Analysis ◽  
In Vivo Tests ◽  
Biocontrol Activity

Evaluation of Ammonium Bicarbonate for Control of Soilborne Peanut Pathogens

1990 ◽  
Vol 17 (1) ◽  
pp. 28-31 ◽  
Author(s):  
T. B. Brenneman ◽  
A. S. Csinos ◽  
P. M. Phipps
Keyword(s):  
Rhizoctonia Solani ◽  
Mycelial Growth ◽  
Sclerotium Rolfsii ◽  
Foliar Spray ◽  
Ammonium Bicarbonate ◽  
In Vitro Studies ◽  
Stem Rot ◽  
Pod Yield ◽  
Sclerotinia Blight

Abstract Ammonium bicarbonate was evaluated for efficacy against southern stem rot and Sclerotinia blight of peanut in Georgia and Virginia, respectively. In vitro studies indicated the material provided little inhibition of mycelial growth by Sclerotinia minor and Sclerotium rolfsii, and negligible inhibition of mycelial growth of Rhizoctonia solani AG-4. However, ammonium bicarbonate did effectively inhibit formation of sclerotia by S. rolfsii in vitro. In the field, it was phytotoxic when applied as a granule or as a foliar spray and in general was not effective in controlling disease or increasing pod yield.

scholarly journals In vitro Antifungal Activity of Plant Extracts, Hydrolates and Essential Oils of Some Medicinal Plants and Control of Cucumber Anthracnose

2019 ◽  
pp. 1-9
Author(s):  
Amanda P. Mattos ◽  
Fabricio P. Povh ◽  
Bruna B. Rissato ◽  
Vítor V. Schwan ◽  
Kátia R. F. Schwan-Estrada
Keyword(s):  
Antifungal Activity ◽  
Medicinal Plants ◽  
Curcuma Longa ◽  
Sclerotium Rolfsii ◽  
Phytopathogenic Fungi ◽  
In Vivo Test ◽  
Activity Effect ◽  
In Vitro Antifungal Activity

Aims: This study is aimed to evaluate the in vitro antifungal activity effect of the crude aqueous extract (CAE), hydrolate (HY) and essential oil (EO) of Corymbia citriodora, Cymbopogon citratus, Cymbopogon flexuosus and Curcuma longa against the phytopathogenic fungi Alternaria steviae, Botryosphaeria dothidea, Colletotrichum gloeosporioides and Sclerotium rolfsii, and assess, in situ, the effectiveness of CAE of medicinal plants in reducing the severity of the cucumber anthracnose. Methodology: The EOs and HYs were obtained by hydrodistillation. The CAEs were prepared by the turbolysis method. Mycelial growth of the fungi was measured daily, by the diametrically opposite method. In the in vivo test, the CAEs were sprayed on the cotyledon leaves of healthy cucumber plants with three days after were inoculated with C. lagenarium. The severity of assessment of the disease was based on a scale of notes. Results: The medicinal plants studied showed antifungal activity against all or almost all pathogens. In general, treatment with CAE and HY of C. longa revealed the highest inhibition against the fungi tested. With the exception of the EO of C. longa, the other EOs showed total inhibition against all the fungi and in all the concentrations tested. Compared to control, in in vivo assays CAE of C. citratus presents a potential for control of cucumber anthracnose reducing the severity of the disease. Conclusion: The medicinal plants studied produce compounds associated with antimicrobial activity.

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