scholarly journals Eficiência de diferentes moléculas na redução dos sintomas da queima das bainhas em arroz e no crescimento de Rhizoctonia solani in vitro

Revista CERES ◽  
2013 ◽  
Vol 60 (2) ◽  
pp. 221-225 ◽  
Author(s):  
Daniel Augusto Schurt ◽  
Fabrício Ávila Rodrigues ◽  
Naiara Fernandes Abreu Souza ◽  
Ricardo Dutra Reis
Keyword(s):  

Este estudo verificou a eficiência da aplicação de diferentes moléculas em reduzir o comprimento relativo da lesão (CRL) da queima das bainhas em arroz. Plantas dos cultivares BR-Irga 409 e Labelle foram cultivadas em solução nutritiva e inoculadas com Rhizoctonia solani, no estádio de máximo perfilhamento. Às 24 horas antes da inoculação, as bainhas das plantas foram pulverizadas com soluções de silicato de potássio (SP), silicato de potássio + fósforo (SP+F), Acibenzolar-S-Metil (ASM), fungicida Carbendazim, quitosana desacetilada (QD), etileno (ET) e fosfito de potássio (FP). Plantas cujas bainhas foram pulverizadas com água destilada serviram como testemunhas. O efeito das moléculas contidas nesses produtos no crescimento micelial de R. solani foi testado in vitro. Para BR-Irga 409, o CRL foi menor com a aplicação do FP, em relação aos demais tratamentos, exceto o Carbendazim. A aplicação do Carbendazim reduziu em 86,1% o CRL, em relação à testemunha. O CRL foi significativamente menor no cultivar BR-Irga 409 do que no 'Labelle', com aplicação do FP. O crescimento micelial de R. solani foi reduzido apenas pelo FP e Carbendazim, em comparação com os demais tratamentos. Não houve diferença significativa entre os tratamentos testemunha, SP e SP+F para a concentração de Si nas bainhas das plantas dos dois cultivares.

1997 ◽  
Vol 46 (5) ◽  
pp. 659-669 ◽  
Author(s):  
J. KEIJER ◽  
M. G. KORSMAN ◽  
A. M. DULLEMANS ◽  
P. M. HOUTERMAN ◽  
J. DE BREE ◽  
...  

Plant Disease ◽  
2016 ◽  
Vol 100 (12) ◽  
pp. 2427-2433 ◽  
Author(s):  
Sahar Arabiat ◽  
Mohamed F. R. Khan

Rhizoctonia damping-off and crown and root rot caused by Rhizoctonia solani are major diseases of sugar beet (Beta vulgaris L.) worldwide, and growers in the United States rely on fungicides for disease management. Sensitivity of R. solani to fungicides was evaluated in vitro using a mycelial radial growth assay and by evaluating disease severity on R. solani AG 2-2 inoculated plants treated with fungicides in the greenhouse. The mean concentration that caused 50% mycelial growth inhibition (EC50) values for baseline isolates (collected before the fungicides were registered for sugar beet) were 49.7, 97.1, 0.3, 0.2, and 0.9 μg ml−1 and for nonbaseline isolates (collected after registration and use of fungicides) were 296.1, 341.7, 0.9, 0.2, and 0.6 μg ml−1 for azoxystrobin, trifloxystrobin, pyraclostrobin, penthiopyrad, and prothioconazole, respectively. The mean EC50 values of azoxystrobin, trifloxystrobin, and pyraclostrobin significantly increased in the nonbaseline isolates compared with baseline isolates, with a resistant factor of 6.0, 3.5, and 3.0, respectively. Frequency of isolates with EC50 values >10 μg ml−1 for azoxystrobin and trifloxystrobin increased from 25% in baseline isolates to 80% in nonbaseline isolates. Although sensitivity of nonbaseline isolates of R. solani to quinone outside inhibitors decreased, these fungicides at labeled rates were still effective at controlling the pathogen under greenhouse conditions.


2020 ◽  
Author(s):  
Irish Mae Bauzon-Cantila ◽  
Jaime C. Silvestre ◽  
Raquel B. Evangelista ◽  
Edralyn Catubay

ABSTRACTRhizoctonia solani Kuhn, the causal pathogen of sheath blight is second most damaging fungal disease in rice. While using chemical fungicides present high detriment to environment, the study investigate the efficacy of treatments composing five biofungicides in three different rates along with a biological agent, chemical check and untreated against the pathogen in in vitro level. In vitro efficacy showed that Melaleuca alternifolia + terpenes at 3.00 ml/L of H20 (T6), Aloe vera powder (Manopol) + Melaleuca oil at 3.00 ml/L of H20 (T15) and at 2.00 ml/L of H20 (T14) and Melaleuca alternifolia + terpenes at 2.00 ml/L of H20 (T5) as very effective (0-10 mm diameter zone of growth) treatments comparable to the chemical check (T17). Therefore, attaining high yield rice while having low risk to environment can always be done.


2020 ◽  
Vol 16 (1) ◽  
pp. 44
Author(s):  
Hanisa Desy Ariani ◽  
Noor Aidawati ◽  
Dewi Arika Adriani

One of the causes of the declining productivity of rice is sheath blight disease caused by the mold Rhizoctonia solani Kuhn. Control of sheath blight disease that is often done by the farmers is by using chemical pesticides (fungicides), which caused environmental problems. One way to reduce the use of pesticides is to biological control by using antagonist bacteria. This study aimed at in vitro test of rhizobacteria in preventing the development of sheath blight disease in rice plants. This research was conducted in the Phytopathology laboratory of Plant Protection Department of Faculty Agriculture, University of Lambung Mangkurat Banjarbaru from March to May 2018. The experiment used a randomized block design with three groups consisting of eight types of rhizobacteria isolates: (r1) Pseudomonas aeruginosa (Barito Kuala), (r2) Bacillus megaterium (Hulu Sungai Tengah), (r3) Azotobacter sp. (Barito Kuala), (r4) Pseudomonas sp. (Hulu Sungai Selatan), (r5) Flavobacterium sp. (Tanah Laut), (r6) Bacillus bodius (Barito Kuala), (r7) Pseudomonas aeruginosa (Hulu Sungai Selatan), (r8) Necercia sp. (Tanah Laut). The results showed that all rhizobacteria have the ability to inhibit the development of R. solani with different percentages of inhibitions. Pseudomonas aeruginosa (Barito Kuala) was the most effective rhizobacteria in inhibiting the development of R. solani.


2010 ◽  
Vol 50 (1) ◽  
pp. 93-97 ◽  
Author(s):  

Effect of Fungal Metabolites and Amendments on Mycelial Growth ofRhizoctonia SolaniA shift towards organic farming suggests amalgamation of organic resources against soil borne plant pathogens. The influence of metabolites of most ubiquitousAspergillusspp., organic amendment extracts and their combined effect withTrichoderma virenswere evaluatedin vitroagainstRhizoctonia solani.The minimum (36.1 mm) growth was attained byR. solaniin co-culture withA. niger.The maximum (42.3 mm) inhibition of mycelial growth of the test organism was observed with culture filtrate ofA. ochraceousfollowed byA. niger, A. fumigatus, A. flavusandA. terreus.Among organic amendment extractants, castor cake exhibited an additive effect on the growth ofT. virens, however, the maximum (41.8 mm) suppressive effect onR. solaniwas observed with vermicompost. With the advance in time, the effect of organic amendment extracts increased markedly. Inhibition potential of culture filtrate mixturte ofA. niger+T. virensandA. ochraceous+T. virensagainstR. solaniwas significantly higher in comparison to the other combinations.


2017 ◽  
Vol 6 (9) ◽  
pp. 1676 ◽  
Author(s):  
Ramaraju Cherkupally ◽  
Srinivasa Reddy Kota ◽  
Hindumathi Amballa ◽  
Bhumi Narasimha Reddy

The antifungal activity of aqueous extracts of nine plants viz, Azadirachta indica, Parthenium hysterophorus, Momordica charantia, Allium sativum, Eucalyptus globules, Calotropis procera, Aloe vera, Beta vulgaris and Datura stramonium were assessed in vitro against Fusarium oxysporum f. sp. melongenae, Rhizoctonia solani and Macrophomina phaseolina, the soil borne phytopathogens. The assessment of fungitoxic effect was carried out by using three different concentrations i.e., 5, 10 and 20% against the test fungi, in terms of percentage of mycelial growth inhibition. The extract of A. sativum completely inhibited the mycelial growth of M. phaseolina at all the concentrations. The extracts of D. stramonium and E. globulus inhibited the mycelial growth of R. solani of 72%, and 70.7% respectively at 20% concentration, that of A. sativum, E. globulus and D. stramonium exhibited inhibition percentage of 63.3%, 61.8% and 61.1% respectively at 20% concentration on Fusarium oxysporum f. sp. melongenae. The application of plant extracts for disease management could be less expensive, easily available, non-polluting and eco-friendly.


2021 ◽  
Author(s):  
Suman Sangwan ◽  
Rajvir Singh ◽  
SUSHEEL GULATI ◽  
Suprita Rana

Abstract A green efficient and facile synthesis of pyrazoles is reported via condensation reaction between substituted aldehydes (1a-1i), malononitrile (2) and 2,4-dinitrophenyl hydrazine (3) in presence of acylated Guar-gum as biocatalyst under solvent-free conditions. The progress of reaction was checked by thin layer chromatography and melting points reported are uncorrected. All synthesized compounds (4a-4i) were characterized by using 1HNMR and FTIR spectral techniques and evaluated for in vitro herbicidal activity against Raphanus sativus L. (Radish seeds). All compounds (4a-4i) were also evaluated for their antifungal activity against Rhizoctonia solani and Aspergillus niger by poisoned food techniques method. Antioxidant activity of synthesized compound was also determined. From activity results, it was found that compound 4f was most active against both Raphanus sativus L. (root) and Raphanus sativus L. (shoot) respectively. Compounds 4e and 4h were found most active against Rhizoctonia solani and Aspergillus niger fungus respectively at highest concentration. Compound 4e has shown maximum percentage DPPH free radical scavenging activity 1.e. 61.47% at 100 µg/mL concentration. Less reaction time, excellent yield of products, mild reaction conditions and simple work-up are some merits of present methodology.


2015 ◽  
Vol 17 (1) ◽  
pp. 143-149 ◽  
Author(s):  
SS GUIMARÃES ◽  
SM MAZARO ◽  
ÁR FREDDO ◽  
A WAGNER JÚNIOR

Foram desenvolvidos dois experimentos com objetivo de avaliar o potencial de preparados de cavalinha (Equisetum sp.) na síntese de metabólitos de defesa em cotilédones de soja (Glycinemax L.) e o efeito sobre o crescimento de Rhizoctonia solani, in vitro. O delineamento experimental utilizado para os experimentos foi inteiramente casualizado em esquema fatorial 3x5 (formas de extração x concentrações), com quatro repetições. As formas de extração foram extrato alcoólico, infusão e maceração, nas concentrações de zero; 1; 10, 20 e 40%. No primeiro experimento foi avaliada a indução de compostos de defesa vegetal em cotilédones de soja em resposta aos derivados a base de cavalinha, sendo quantificada a atividade da enzima fenilalanina amônia-liase (FAL), via espectofotometria, a fitoalexina gliceolina, e o teor de fenóis totais. No segundo experimento, in vitro, a unidade experimental foi uma placa de Petri, sendo os preparados de cavalinha incorporados ao meio BDA (Batata-dextrose e Agar) e avaliado o crescimento micelial de R. Solani. Os preparados de extrato alcoólico, infusão e maceração de cavalinha apresentaram capacidade de indução das fitoalexinas gliceolinas em cotilédones de soja, bem como, ativaram o metabolismo de compostos fenólicos. Entre os preparados, o extrato alcoólico e a maceração, se sobressaem sobre a infusão. Os preparados de extrato alcoólico, infusão e maceração de cavalinha em todas as suas concentrações inibem o crescimento do fungo R. solani, in vitro.


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