scholarly journals Comparative efficacy of essential oils of three aromatic plants as alternatives in the control of Phytophthora spp., agent of cocoa tree (Theobroma cacao L.) black pod disease in Côte d'Ivoire

2021 ◽  
Vol 15 (4) ◽  
pp. 1398-1409
Author(s):  
Klotioloma Coulibaly ◽  
F. J.M. Koffi Kassi ◽  
Adama Ouattara ◽  
B. F. Gogbe-Dibi ◽  
P. Walet N’guessan ◽  
...  

This study aimed at comparing the efficacy of essential oils from three aromatic plants species (Cymbopogon citratus, Eucalyptus citriodora and Ocimum gratissimum) in vitro and in vivo against two Phytophthora strains (Phytophthora palmivora and P. megakarya) in a view to developing new biofongicides for the control of cocoa tree black pod disease. Essential oils were applied at four different concentrations (0.5; 1; 3 and 5 mL/L) in vitro and in vivo on leaf discs of three cocoa clones (NA32, PA150 and SCA6) whichsusceptibility is known. As results, all three essential oils significantly (p˂ 0.05) reduced in vitro mycelial growth of both Phytophthora strains and also reduced the leaf susceptibility to these strains. Inhibition rates in vitro of Phytophthora strains mycelial growth ranged from 83.80 to 100% for the essential oils of Cymbopogon citratus and Ocimum gratissimum species and from 17.7 to 100% for which of Eucalyptus citriodora species. In the biotests, the leaf susceptibility index of clone NA32 (susceptible) was reduced from 3.14 to 0.40. This correspond to reduction rates ranged from 64.87 to 86.70% of leaf susceptibility to both Phytophthora strains. Essential oils (HS and HO) from Cymbopogon citratus and Ocimum gratissimum species were most effective than which from Eucalyptus citriodora species. However, all three essential oils revealed antifungal properties. Therefore, they could be recommended as biofungicides for a sustainable control of cocoa tree black pod disease in Côte d'Ivoire.    

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Nathan Habila ◽  
Abel S. Agbaji ◽  
Zakari Ladan ◽  
Isaac A. Bello ◽  
Emmanuel Haruna ◽  
...  

Essential oils (EOs) fromCymbopogon citratus(CC),Eucalyptus citriodora(EC),Eucalyptus camaldulensis(ED), andCitrus sinensis(CS) were obtained by hydrodistillation process. The EOs were evaluated in vitro for activity againstTrypanosoma brucei brucei(Tbb) andTrypanosoma evansi(T. evansi). The EOs were found to possess antitrypanosomal activity in vitro in a dose-dependent pattern in a short period of time. The drop in number of parasite over time was achieved doses of 0.4 g/ml, 0.2 g/mL, and 0.1 g/mL for all the EOs. The concentration of 0.4 g/mL CC was more potent at 3 minutes and 2 minutes for Tbb andT. evansi, respectively. The GC-MS analysis of the EOs revealed presence of Cyclobutane (96.09%) in CS, 6-octenal (77.11%) in EC, Eucalyptol (75%) in ED, and Citral (38.32%) in CC among several other organic compounds. The results are discussed in relation to trypanosome chemotherapy.


2017 ◽  
Vol 9 (3) ◽  
pp. 443 ◽  
Author(s):  
Jean-Fabrice Yala ◽  
Rolande Mabika Mabika ◽  
Brahima Camara ◽  
Seydou Tuo ◽  
Alain Souza ◽  
...  

<p>The purpose of this study was to assess <em>in vitro</em> the activity of four essential oils (<em>Cymbopogon citratus, Eucalyptus citriodora, Lippia multiflora, Melaleuca quinquenervia</em>) and the biobactericide Neco® on Gram-positive bacteria.</p><p><strong>T</strong>he aromatogram and antibiogram were assessed by the agar well diffusion method and the Muller Hinton disk-agar diffusion method, respectively. Also, the minimum inhibitory concentration and the minimum bactericidal concentration were determined by the microdilution method in liquid medium.</p><p>The aromatogram showed that the biobactericide Neco® induced the largest inhibition diameters (34.53 ± 11.82 - 43.92 ± 5.38 mm) of all strains combined, followed by the essential oils of <em>Eucalyptus Citriodora</em> (30.01 ± 3.02 - 41.89 ± 1.77 mm) and <em>Lippia multiflora</em> (20.72 ± 4.72 - 37.61 ± 2.80 mm). However, the essential oils of <em>Melaleuca quinquenervia</em> (19.99 ± 3.93 - 26.20 ± 13.27 mm) and <em>Cymbopogon citratus</em> (13.52 ± 3.59 - 29.08 ± 2.35 mm) had the smallest inhibition diameters. Moreover, the comparison of the activities of the aromatogram and antibiogram revealed generally that activities were higher with essential oils than with antibiotics.</p><p>At the end of this study, the essential oils of <em>Cymbopogon citratus</em>, <em>Eucalyptus citriodora, Lippia multiflora, Melaleuca quinquenervia</em> and the biobactericide Neco® had an antibacterial activity on Gram+ bacteria.</p><p><strong><br /></strong></p>


Author(s):  
Dahou Moutassem ◽  
Yuva Bellik ◽  
Mohamed El Hadi Sannef

This study evaluated the toxicity and repellent activities of essential oils (EOs) against Sitophilus granarius (Linnaeus, 1758), both in vitro and in vivo conditions. The EOs obtained from Thymus pallescens Noë. (Lamiaceae) and Cymbopogon citratus Stapf. (Poaceae) were analyzed by GC-MS, and revealed that carvacrol (56.64%) and geraniol (20.8%) as the respective major components. T. pallescens EO was found to be a more effective toxicant, with LC<sub>50</sub> and LC<sub>90</sub> values of 9.3 and 34.6 µL/mL, respectively, in the contact test vs 8.2 and 25.3 µL/mL in the fumigation test. T. pallescens EO showed also a stronger repellent effect with values ranging from 83.4% to 100%. In the in vivo test, the survival probability decreased from 99.9 to 2.48% among insects exposed to T. pallescens EO. These data demonstrated that EOs could be considered effective alternatives to chemical insecticides, providing pest control for stored products in an ecologically sustainable manner.


2016 ◽  
Vol 2016 ◽  
pp. 1-4 ◽  
Author(s):  
Valéria Maria Lara ◽  
Adriano Bonfim Carregaro ◽  
Deise Flores Santurio ◽  
Mariangela Facco de Sá ◽  
Janio Moraes Santurio ◽  
...  

This study evaluated thein vitroantibacterial activity of essential oils fromLippia graveolens(Mexican oregano),Origanum vulgaris(oregano),Thymus vulgaris(thyme),Rosmarinus officinalis(rosemary),Cymbopogon nardus(citronella),Cymbopogon citratus(lemongrass), andEucalyptus citriodora(eucalyptus) againstEscherichia coli(n=22) strains isolated fromAlouattaspp. feces. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined for each isolate using the broth microdilution technique. Essential oils of Mexican oregano (MIC mean = 1818 μg mL−1; MBC mean = 2618 μg mL−1), thyme (MIC mean = 2618 μg mL−1; MBC mean = 2909 μg mL−1), and oregano (MIC mean = 3418 μg mL−1; MBC mean = 4800 μg mL−1) showed the best antibacterial activity, while essential oils of eucalyptus, rosemary, citronella, and lemongrass displayed no antibacterial activity at concentrations greater than or equal to 6400 μg mL−1. Our results confirm the antimicrobial potential of some essential oils, which deserve further research.


2009 ◽  
Vol 11 (4) ◽  
pp. 399-406 ◽  
Author(s):  
P.R. Carnelossi ◽  
K.R.F. Schwan-Estrada ◽  
M.E.S. Cruz ◽  
A.T. Itako ◽  
R.M. Mesquini

Os subprodutos de plantas medicinais têm sido estudados como uma alternativa para o controle de doenças de plantas visando amenizar e/ou reduzir o uso abusivo de agrotóxicos, principalmente em condições pós-colheita. Assim, este trabalho teve como objetivo avaliar, in vitro e in vivo, o controle de Colletotrichum gloeosporioides, agente causal da antracnose do mamão em pós-colheita, por óleos essenciais (OEs) de Cymbopogon citratus, Eucalyptus citriodora, Mentha arvensis e Artemisia dracunculus. Para inibição do crescimento micelial in vitro, os OEs foram incorporados ao BDA (Batata-dextrose-ágar) tendo-se observado a inibição total ou parcial do crescimento micelial e da esporulação deste fitopatógeno, dependendo do óleo essencial utilizado. No ensaio in vivo utilizaram-se os OEs de C. citratus (1%) e E. citriodora (1%). A inoculação com o fitopatógeno foi concomitante e 24 h após os tratamentos alternativos, que foram: óleos essenciais de C. citratus e de E. citriodora (1%) e biomassa cítrica (150 mL 100 L-1) (Ecolife®). Os parâmetros avaliados foram severidade da doença, redução da massa, diâmetro, comprimento final dos frutos, pH e a concentração de sólidos solúveis totais (ºBrix). Pode-se observar que, no controle da doença, os frutos tratados e imediatamente inoculados com o fitopatógenos apresentaram maior AACPD (Área Abaixo da Curva do Progresso da Doença). Porém, frutos tratados e inoculados 24 h após os tratamentos apresentaram maior controle da doença, confirmando o potencial dos óleos essenciais testados no presente trabalho.


Author(s):  
Yao Kouadio Jacques-Edouard ◽  
Kouamé Konan Didier ◽  
Kouamé Koffi Gaston ◽  
Kassi Koffi Fernand Jean-Martial ◽  
N’guessan Aya Carine ◽  
...  

The sugarcane smut disease caused by Sporisorium scitamineum occurs in all production areas. In order to contribute to the management of this disease, a study was carried out in vitro conditions. The aim of this study was to evaluate the antifungal efficacy and to determine the inhibitory concentration of the essentials oils of Ocimum gratissimum, Zingiber officinale and Cymbopogon citratus upon two strains B and Z of Sporisorium scitamineum. These oils were tested on mycelial growth of colonies, spores’ production and teliospores germination. The results showed a variable fungitoxic effect of the oils according to doses. Mycelial growth and spores production were totally inhibited (100%) from 1000 ppm by all the oils. The 90% inhibitory concentrations (IC90) obtained were 880.37 ppm, 847.83 ppm and 805.75 ppm for Ocimum gratissimum, Zingiber officinale and Cymbopogon citratus, respectively. The germination of teliospores was completely reduced by the three essential oils from 500 ppm upwards. Propiconazole had strong inhibitory effects at 400 ppm with a very low IC50 and the IC90 ranged from 305 ppm to 323.36 ppm. Moreover, at the level of the strains, no difference in resistance was observed These oils could provide a good means of controlling sugarcane smut.


2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 132-132
Author(s):  
Sergio Calsamiglia ◽  
Maria Rodriguez-Prado ◽  
Gonzalo Fernandez-Turren ◽  
Lorena Castillejos

Abstract In the last 20 years there has been extensive in vitro research on the effects of plant extracts and essential oils on rumen microbial fermentation. The main objectives have been to improve energy metabolism through a reduction in methane emissions and an increase in propionate production; and to improve protein metabolism by reducing proteolysis and deamination. While the positive results from in vitro studies has stimulated the release of commercial products based on blends of essential oils, there is limited in vivo evidence on the rumen fermentation and production performance effects. A literature search was conducted to select in vivo studies where information on rumen fermentation and animal performance was reported. For dairy cattle, we identified 37 studies of which 21 were adequate to test production performance. Ten studies reported increases and 3 decreases in milk yield. For beef cattle, we identified 20 studies with rumen fermentation profile and 22 with performance data. Average daily gain improved in 7 and decreased in 1 study. Only 1 out of 16 studies reported an improvement in feed efficiency. Data indicate that out of more than 500 products tested in vitro, only around 20 have been tested in vivo in different mixtures and doses. The use of statistical approaches will allow to describe the conditions, doses and responses in dairy and beef cattle performance. The search for postruminal effects offers another alternative use. Evidence for effects on the intestinal and systemic effects on the immune system and antioxidant status (i.e., capsicum, garlic, eugenol, cinnamaldehyde curcuma, catechins, anethol or pinene), and in the modulation of metabolic regulation (capsicum, cinnamaldehyde, curcuma or garlic) may open the opportunity for future applications. However, stability of the product in the GI tract, description of the mechanisms of action and the impact of these changes on performance needs to be further demonstrated.


2010 ◽  
Vol 36 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Cláudia Regina Dias-Arieira ◽  
Lucas da Rocha Ferreira ◽  
Jailson de Oliveira Arieira ◽  
Edenilson Gonçalves Miguel ◽  
Mateus Augusto Donega ◽  
...  

A flor-preta é uma das doenças mais importantes do morangueiro e a busca por alternativas de controle tem sido uma constante, principalmente em áreas de cultivo orgânico. Assim, objetivou-se avaliar a eficiência, in vitro e in vivo, dos óleos de Eucalyptus citriodora e Azadirachta indica no controle de Colletotrichum acutatum em morangueiro. No experimento in vitro determinou-se a inibição do crescimento micelial quando o fungo foi submetido aos extratos nas concentrações de 0; 0,25; 0,5; 1,0 e 1,5%. No campo, avaliou-se o controle da doença com a aplicação dos óleos nas concentrações de 0, 0,5 e 1,0%, pulverizados em intervalos de 7, 15 e 30 dias, em plantas inoculadas com suspensão de 10(6) conídios/mL. As avaliações foram realizadas semanalmente, observando-se a ocorrência e tamanho de lesões no pedúnculo e nos frutos, abortamento floral, produtividade, e ocorrência natural da doença. In vitro todos os tratamentos apresentaram redução significativa do crescimento micelial do fungo quando comparados ao controle. No campo, apenas o óleo de nim apresentou efeito significativo, reduzindo o abortamento floral e a ocorrência de frutos doentes advindos de flores inoculadas. Porém, maior ocorrência natural de doença foi observada quando a dosagem de 1,0% foi aplicada semanalmente.


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