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The essential oils of Tagetes filifolia have potential for controlling insects that are biotransmitters of virus in plants. The objective of the present study was to evaluate the composition of the essential oil of 78 accessions of T. filifolia of the south–central region of México, established in Chapingo, México. When the plants presented flowering, the extraction of the essential oils was made by simple distrillation process using 500 g of tissue of the complete plant. The chemical composition of the oil was determined with gas chromatography coupled to masses. The principal components of the oil were 4–alilanisole and trans–anethole (4–propenilanisole), individually or in mixture: 1.3% of the accessions only with anethole, 7.7% of the accessions only with alilanisole and 91% of accessions with mixture. In the accessions with mixture of anethole and alilanisole, the proportion of these chemical compounds was variable.
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... Although Mexico's plant diversity is rich, the biological properties of many plants are still unknown; these could probably have potential to control D. citri (Serrato et al., 2008;Mendoza-García et al., 2015). Some species from the Apiaceae, Asteraceae, Brassicaceae, and Piperaceae families have been identified as promising sources of compounds with pesticide properties (Mafra-Neto et al., 2015). ...
... Oil extracts from Tagetes species contain active ingredients, such as trans-anethole, allylanisole, β-caryophyllene, ocimenone, piperitone, and tagetone, that have toxic, repellent, and/or inhibitive effects on insect reproduction and growth (Xu et al., 2012). Approximately 30 Tagetes species exist in Mexico, which is half of the recorded species in America (Serrato et al., 2008). Despite such diversity, there are few studies on the biological activity of the substances they contain (Serrato et al., 2008;Camarillo et al., 2009;Mendoza-García et al., 2015). ...
... Approximately 30 Tagetes species exist in Mexico, which is half of the recorded species in America (Serrato et al., 2008). Despite such diversity, there are few studies on the biological activity of the substances they contain (Serrato et al., 2008;Camarillo et al., 2009;Mendoza-García et al., 2015). ...
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Diaphorina citri Kuwayama (Hemiptera: Liviidae) is an invasive species in America and is the main vector of the pathogen associated with Huanglongbing, a deadly disease of citrus plants in the world. The management of such a problem includes the intensive use of insecticides to reduce vector populations and risk of pathogen transmission. As an alternative to synthetic insecticides to control D. citri, the present study determined the chemical composition of diverse plant essential oils and assessed the toxicity and repellency of oil extracts against D. citri. Their chemical composition and abundance were determined by gas chromatography coupled to mass spectrometry. Adults and nymphs were exposed to leaf citrus discs treated by spraying or immersion with different oil extract concentrations. Repellency was assessed by exposing adults to treated leaves in experimental arenas and determining the number of insects remaining on the leaf after different time periods compared with the control. The main oil compounds in the tested plants were anethole, verbenone, 4-ethyl-4-methyl-1-hexene, 4-allylanisole, and trans-tagetone. Oils from Rosmarinus officinalis L. and Schinus molle L. caused no repellent or insecticide effects on D. citri. In contrast, oil extracts from the Foeniculum vulgare Mill. and Tagetes species were toxic and/or repellent for both adults and nymphs. There was a positive relationship between toxicity and concentration. Oil extracts from Tagetes lucida, T. coronopifolia, and T. terniflora were repellent (> 92%) at 40 mg mL-1; this was correlated with the concentration and decreased over time. Essential oils extracts from the Tagetes species could represent a potential defense that could be integrated into the management of D. citri.
... Genus Tagetes distributes across the American continent and includes more than 50 species, mainly found in Mexico (Kurpis et al. 2019). Mexican culture employs Tagetes for various purposes: antioxidant, medicine, food pigment, flavouring, perfume, resin, ornamental and insecticide; in agriculture it is used as a nematicide, larvicide, attractant or insect repellent, and as fertilizer (Serrato-Cruz et al. 2008). The most used species of Tagetes in pest control are. ...
... To control nematodes, Tagetes is applied Migunova and Sasanelli (2021) in the form of organic manure to the plants or in the form of aqueous extracts and powders, and it is used in crop rotation. Pyrethrins and thiophenes (such as α-terthienyl) found in marigold roots are responsible for its nematocidal and nematostatic activity (Serrato-Cruz et al. 2008;Hamaguchi et al. 2019). Rattlepod plants (Crotalaria spp.) for their part are not nematode hosts and are used as a preceding crop or cover crop to suppress nematode populations by disrupting their life cycle (especially at the reproductive stage) (Osei et al. 2010). ...
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Root-knot nematodes (RKN) are sedentary parasites of the roots of plants and are considered some of the most damaging pests in agriculture. Since RKN target the root vascular system, they provoke host nutrient deprivation and defective water transport, causing above-ground symptoms of growth stunting, wilting, chlorosis, and reduced crop yields. In Mexico RKN infestations are primarily dealt with by treating with synthetic chemically based nematicides that are preferred by farmers over available bioproducts. However, due to environmental and human health concerns chemical control is increasingly restricted. Biological control of RKNs can help reduce the use of chemical nematicides as it is achieved with antagonistic organisms, mainly bacteria, fungi, other nematodes, or consortia of diverse microorganisms, which control nematodes directly by predation and parasitism at different stages: eggs, juveniles, or adults; or indirectly by the action of toxic diffusible inhibitory metabolites. The need to increase agricultural production and reduce negative environmental impact creates an opportunity for optimizing biological control agents to suppress nematode populations, but this endeavour remains challenging as researchers around the world try to understand diverse control mechanisms, nematode and microbe life cycles, ecology, metabolite production, predatory behaviours, molecular and biochemical interactions, in order to generate attractive products with the approval of local regulatory bodies. Here, we provide a brief review of the biology of the genus Meloidogyne, biological control strategies, and a comparison between chemical and bioproducts in the Mexican market, and guidelines emitted by national agencies to ensure safety and effectiveness of new developments.
... Los aceites esenciales (AE) de plantas presentan actividad antibacteriana, antifúngica, acaricida e insecticida (Cheng et al. 2003), el empleo de aceites esenciales extraídos es una opción importante para controlar y eliminar insectos depredadores de los cultivos y de granos almacenados, causantes de fuertes daños a la agricultura y en el almacenamiento, constituyendo una tecnología limpia dentro del manejo ecológico de plagas (Serrato et al. 2005;Serrato 2008), además son mezclas complejas que se originan del metabolismo secundario de las plantas (Camarillo et al. 2009 (Olmedo et al. 2015). ...
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RESUMENLos aceites esenciales son mezclas volátiles de terpenos obtenidas de plantas, muchos de estos productos poseen propiedad insecticida, siendo una alternativa para la eliminación de insectos depredadores de granos almacenados, constituyendo una tecnología limpia dentro del manejo ecológico de plagas. El deterioro en el almacenamiento de granos como es el maíz produce una gran pérdida y entre las causas están los insectos como el gorgojo Pagiocerus frontalis. El objetivo de la presente investigación fue evaluar la actividad insecticida del aceite esencial de Pampa Anís (Tagetes filifolia Lag.) sobre el gorgojo del maíz (Pagiocerus frontalis). La metodología utilizada en la extracción del aceite esencial (AE), fué por hidrodestilación con trampa de Clevenger; su composición química por cromatografía de gases – espectrometría de masas (CG-EM) y para la determinación del efecto insecticida se halló la concentración letal media CL50 y CL90, aplicándose el método de impregnación de papel, evaluándose las concentraciones de 0,1; 0,5; 1; 2; 3; 4; 5; 6 y 10 % de AE, durante 72 horas de exposición. La CL50 sobre P. frontalis fue 0.61 % (v/v) y la CL90 fue 1,96 % (v/v) (P < 0,05). A partir de los resultados se concluye que el aceite esencial de T. filifolia puede convertirse en una posible alternativa potencial a los insecticidas sintéticos, en el manejo de P. frontalis.Palabras Clave: Aceite esencial, gorgojo del maíz, insecticida natural, Pagiocerus frontalis, pampa anís, Tagetes filifolia.
... etanólico de raíz del anisillo Tagetes filifolia Lag. a 100 ppm en adultos de Bemisia tabaci (Gennadius, 1889) mientras que Serrato et al. (2003) estimaron una Concentración de Repelencia Media (CR 50 ) de 7,18 mg/mL del aceite esencial de la parte aérea de plantas en floración de T. filifolia (Lagasca) para adultos de B. tabaci y Trialeurodes vaporariorum (Westwood, 1856) (Hemiptera: Aleyrodidae). Aunque el aceite de poblaciones de T. filifolia nativas de México contiene alta proporción de anetol, aún no se cuenta con información sobre la relación entre el aceite de diferentes partes de esta planta o la concentración de éste y los efectos biológicos que pueden producirse en T. vaporariorum (Serrato et al. 2008). ...
Article
Con la finalidad de proteger a los cultivos de las plagas sin provocar más daño al ambiente y al humano, se ha generado la búsqueda de nuevos insecticidas y repelentes amigables y efectivos. El objetivo de este trabajo fue comparar la actividad biológica de trans-anetol, de extractos acuosos, aceites y turbios, obtenidos de la destilación por arrastre de vapor, de flores, hojas y planta completa de Tagetes filifolia sobre la mosca blanca Trialeurodes vaporariorum. La repelencia se evaluó al exponer dentro de un olfatómetro adultos del insecto a un disco tratado por 24 h, mientras que la toxicidad a adultos, inhibición de la oviposición y del crecimiento de ninfas, se evaluó mediante el confinamiento de adultos en una jaula entomológica sobre una hoja tratada y mediante el tratamiento de ninfas con el método de aspersión. Los extractos acuosos y turbios de las diferentes estructuras no causaron repelencia, ni efecto insecticida. En cambio, los aceites y el trans-anetol causaron alta mortalidad (69%) y repelencia de adultos (70%), inhibición de la oviposición (90%), interferencia en el crecimiento ninfal (50%) y emergencia de adultos (50%), pero no afectaron la duración del ciclo de T. vaporariorum (21-30 días). El trans-anetol y el aceite floral tuvieron mayor efecto sobre adultos de mosca blanca, a nivel de la Concentración Letal y Concentración de Repelencia. La actividad biológica de los extractos se relacionó positivamente con la concentración. Por tanto, los aceites de T. filifolia evaluados representan una herramienta útil en el manejo integrado de T. vaporariorum.
... Los pigmentos en las flores y los metabolitos secundarios sintetizados en los órganos vegetativos en la mayoría de las especies de Tagetes les han conferido importancia en la industria agrícola, alimenticia, cosmética y medicinal, entre otras. En este sentido las investigaciones sobre Tagetes se han dirigido principalmente a la caracterización de sus compuestos químicos debido a la actividad biológica sobre varios organismos patógenos (Tereschuk et al. 1997, Dharmagadda et al. 2005, Romagnoli et al. 2005, Céspedes et al. 2006, Pérez-Gutiérrez et al. 2006, Serrato-Cruz et al. 2008, Barajas-Pérez et al. 2011. Estudios etnobotánicos corroboran la importancia de al menos el 10 % de las especies de Tagetes en diferentes aspectos tradicionales de la cultura mexicana (García-Sánchez et al. 2012, Serrato-Cruz 2014, Pérez-Ortega et al. 2016. ...
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Antecedentes: Tagetes contiene cerca de 55 especies, su mayor centro de diversificación se encuentra en México con 35. Cerca del 10 % de las especies tienen importancia en el ámbito cultural y económico. A la fecha, se carece de estudios anatómicos en la mayoría de ellas. Pregunta: ¿Existen caracteres anatómicos foliares de valor diagnóstico que permitan discriminar entre las nueve especies de Tagetes estudiadas? Especies de estudio: Tagetes lacera, T. lemmonii, T. linifolia, T. lucida, T. lunulata, T. micrantha, T. parryi, T. stenophylla, T. zypaquirensis. Sitio de estudio y fecha: Áreas de distribución natural en el Altiplano Mexicano, Faja Volcánica Transmexicana y Campo Experimental de Fitotecnia, Universidad Autónoma Chapingo, Texcoco, Estado de México, durante el 2017. Métodos: Se recolectaron ejemplares botánicos. Sus hojas fueron fijadas y sometidas a técnicas convencionales de anatomía vegetal, se diafanizaron e incluyeron en parafina para su observación y análisis. Resultados: Las especies de Tagetes desarrollan hojas enteras y pinnatisectas, el patrón de venación secundaria fue eucamptódromo tornándose reticulódromo distalmente y broquidódromo simple y festoneado. La venación última marginal fue incompleta excepto de T. lunulata. Se observaron abundantes y diversos tricomas, mesofilo dorsiventral e isolateral, haces colaterales con vaina y canales en el mesofilo y en la vena media. Conclusiones: La arquitectura y la anatomía foliar de las especies estudiadas revela caracteres comunes en Asteraceae. Sin embargo, en Tagetes el tipo de tricomas, mesofilo, tamaño de los canales y esclerénquima asociada a los haces vasculares son importantes.
... cavities, ducts, and glandular trichomes) in roots, stems, leaves, phyllaries, and flowers (Van Thiegem 1872, Del Fueyo 1986, Poli et al. 1995, Simon et al. 2002; the essential oils of many Tagetes species have been extensively studied for their medicinal, nutritional, cosmetical, and bioactive properties (e.g. Cestari et al. 2004, Babu & Kaul 2007, Serrato-Cruz et al. 2008, Camarillo de la Rosa et al. 2009, López et al. 2009, Díaz-Cedillo & Serrato-Cruz 2011, Dixit et al. 2013, Cornelius & Wycliffe 2015, Mendoza-García et al. 2015, Singh et al. 2015, Gakuubi et al. 2016). ...
Article
During the revision of the genus Tagetes, we detected the need for typifications and taxonomical rearrangements in North and Central American taxa. We analyzed type and non-type specimens, morphological traits, geographical distributions, protologues, and biographies of authors and collectors. As a result, we designated 12 lectotypes and one epitype for the following plant names: T. clandestina, T. florida, T. lemmonii, T. lucida, T. macroglossa, T. micrantha, T. nelsonii, T. oligocephala, T. schiedeana, T. signata, T. signata var. pumila and T. triradiata. In addition, we placed T. oligocephala in synonymy within T. foetidissima and clarified type localities of T. oligocephala and T. schiedeana.
... A dietary antioxidant is a substance that is part of everyday foods and can prevent the adverse effects of reactive species on the normal physiological functions of humans 16 . The anethole known as alilanisol, has larvicidal, insecticidal and antifungal activity and provides an intense and light smell and flavor to sweet anise 17 . ...
... Las especies de Tagetes de América presentan variabilidad química que no se ha estudiado ampliamente, y en el caso de México, este género se distribuye en los lugares más diversos de la geografía del país, por lo que se estima que ocurre un importante fenómeno de variabilidad en el perfil de aceites esenciales (Serrato, 2014); por ejemplo, en T. minuta se reporta variación en la composición de aceite esencial asociada con la diversidad de hábitats de las muestras (Zygadlo et al., 1990) y se ha confirmado la existencia de quimiotipos (Gil et al., 2000). En T. filifolia de la región centro-sur de México también se ha registrado el mismo fenómeno (Serrato-Cruz et al., 2008). ...
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La enorme riqueza natural de Tagetes lucida Cav. en el Estado de México no ha sido considerada como objeto de estudios fitoquímicos, una información básica para el desarrollo de bioplaguicidas. En este estudio se determinó la composición química del aceite esencial de poblaciones de T. lucida del norte y sur del Estado de México, donde se detectaron seis tipos de suelo y seis condiciones climáticas. El aceite de tallos florales de 14 poblaciones se obtuvo por hidrodestilación y se analizó por cromatografía de gases y espectrometría de masas (CG/EM) y se identificaron 44 compuestos químicos, 32 % de ellos en poblaciones del norte (9 a 13 compuestos) y 68 % en poblaciones del sur (16 a 23 compuestos). Los rendimientos de aceite esencial fueron de 0.005 a 0.02 % (mL 100 g-1 de tejido seco), en poblaciones del norte, y de 0.0001 a 0.0005 % en las del sur. Los compuestos mayoritarios en poblaciones del norte, de clima templado frío, fueron fenilpropenos: anetol, estragol (35 y 46 %, respectivamente en la población Jilotepec) y metil eugenol (56 y 64 % en poblaciones Acambay y Atlacomulco, respectivamente). En poblaciones del sur, de clima cálido, los compuestos mayoritarios fueron monoterpenos: acetato de geranilo (25 a 33 % en Coatepec Harinas; 12 a 27 % en Villa Guerrero; 23 a 40 % en Ixtapan de la Sal; 31 % en Tonatico y 19 % en Pilcaya) y β-ocimeno (14 a 16 % en Coatepec Harinas; 15 a 23 % en Ixtapan de la Sal y Villa Guerrero; 24 % en Tonatico y Pilcaya). Los compuestos β-mirceno, β-ocimeno y linalool fueron comunes en todas las poblaciones y la presencia acetato de geranilo se reporta por vez primera para el género Tagetes.
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Marigolds (Tagetes spp.) are multifunctional flowering plants belonging to the Asteraceae family, well-known and widespread for their ornamental value and many other uses. In this study, morphological differences and genetic relationships among 21 cultivars of three species of marigold (Tagetes patula, T. erecta and T. tenuifolia) were analysed. Results have revealed obvious differences among genotypes, starting from the morphological characteristics of the seeds and their capacity to germinate to adult plant morphological characteristics, both between cultivars and species. The genotypic differences were manifested in considerable variation in the development of phenological stages and the main morphological traits of plants and flowers. PCA and hierarchical clustering analyses of morphological traits revealed a homogeneous grouping of cultivars within each species, except for Orion, belonging to T. patula, which was closer to T. erecta cultivars. A subset of 13 cultivars from the three species was subjected to SSR analysis, revealing considerable genetic diversity and good separation between T. patula on the one side and T. erecta and T. tenuifolia on the other. The observed heterozygosity was much lower than the expected heterozygosity, revealing a high degree of fixation. The results reveal that the three species evaluated have considerable morphological and genetic diversity, which has important implications for assessing genetic diversity, conserving germplasm and selecting parents for new breeding works in marigolds.
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Species of the genus Tagetes (Astereceae) have shown important medicinal and biological properties. Many Tagetes species are native from Mexico, however, there are few studies on their volatiles. The objective of the present study is to characterize the volatiles of Tagetes nelsonni Greenm commonly known as “Chik chawa”, which is a plant used in some regions of Chiapas State, Mexico for medicinal purposes. Our work was focused to extract and to identify the T. nelsonii volatiles using Solid Phase Microextraction (SPME) and Gas Chromatography-Mass Espectrometry (GC-MS) respectively. The compounds biosynthesized by T. nelsonii are a mixture of terpenes. The major volatile components are (E)-β-tagetone (43-9%) and dihydrotagetone (20.7%), followed by trans-β-ocimene, eucaliptol, limonene and β-cubebene. T. nelsonni contains fragant compounds as α and β-pinene, trans-β-ocimene, limonene, linalool, (E) and (Z)-tagetones, dihydrotagetone and cis and trans-tagetenone with potential to be used for cosmetic, pharmaceutical purposes and to help to control insect pest of plant problems.
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The essential oil from the aerial parts of Tagetes filifolia Lag. (Asteraceae) from Cusco Department, Perú, was obtained by hydrodistillation in 0.47% (v/w) yield related to dry weight. By GC–MS analysis 57 compounds, accounting for 99.2% of the oil, were identified. Phenylpropanoids constitute the great majority of the oil, with cis-anethole (68.2%) and estragole (13.7%) as main constituents. © 1998 John Wiley & Sons, Ltd.
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Achillea millefolium L. (yarrow) is a perennial herb, native to Europe and Asia and growing wild at different environmental conditions (altitude, soil). Since ancient ages, yarrow leaves and flowers have been used as medicinals, in cosmetics, and food industries. Plant height, number of inflorescences, fresh biomass and essential oil content, yield and composition of Achillea millefolium L. grown at different altitudes (from 250 m to 1,100 m) were studied. Plant height (from 54 cm to 77 cm) and essential oil content per plant (from 0.16% to 0.22%) were not significantly affected by environment, while the number of inflorescences/plant, fresh biomass herb yield (from 5 Mt/ha to 12 Mt/ha) and essential oil yield (from 1.12 Kg/ha to 2.51 Kg/ha) were significantly influenced by environment.As far as the composition of essential oils is concerned, there was a remarkable change in some monoterpenes and sesquiterpenes: in particular α- and β-thujone were not present in oils from fields at a higher altitude, suggesting that their synthesis depends on both genetic and environmental factors. The concentrations of lavandulyl acetate, chama-zulene, P-caryophyllene, a-humulene and y-curcumene + germacrene D are greatly influenced by environmental growing conditions. From a qualitative point of view, essential oils from different environmental condition have different characteristics.
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The essential oil from aerial parts of Tagetes mandonii Sch. Bip. (Asteraceae) was obtained by hydrodistillation. The oil content was 0.43% (v/w), on a dry weight basis. The oil composition was analysed by GC and GC-MS; 62 of the 71 compounds detected were identified, accounting for 96.8% of the oil, cis-(11.8%) and trans-ocimene (15.2%) were the main components, with appreciable amounts of ocimenones (12.9%), tagetones (12.5%), limonene (7.9%) and, in sesquiterpene fraction, spathulenol(6.9%). cis-Anethole (9.2%) is the main constituent of the phenylpropanoid group (12.7%). Copyright (C) 1999 John Wiley & Sons, Ltd.
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Resumen En dos especies silvestres de Tagetes productoras de aceites esenciales se evaluaron los efectos que produce el deshierbe, la escarda y la separación entre plantas sobre características vegetativas y reproductivas en Chapingo, México, en el periodo junio-noviembre de 2001. En T. Foetidissima , se utilizó deshierbe manual o con escarda (1a ó 2a), la altura de planta (AP) fue 94-99 cm, diámetro de follaje (DF) 122-128 cm, número de capítulos (NC) 530-850 y biomasa por planta (BP) 5.3 g y por metro cuadrado (BMC) 1.3 kg, comparados con el testigo con malezas (AP 75 cm, DF 30 cm, NC 72, BP 3.3 g, BMC 620 g). Con mayor separación entre plantas, AP fue la misma y van aumentando DF, NC, BP y BMC. La mayor producción de BMC de 2.6 kg se obtuvo a 30x30 con dos escardas. En T. filifolia, la mayor producción de biomasa se obtuvo con separación de 20x20 sin roturar el suelo. Palabras Clave : Distanciamiento entre plantas, roturación del suelo, producción de biomasa, recursos genéticos. Abstract The effects of weeding, shallow tilling, and plant spacing on the vegetative and reproductive characteristics of two wild species of Tagetes, producers of essential oils, were evaluated during the period June-November 2001, in Chapingo, Mexico. In the case of T. foetidissima, hand weeding and shallow tilling produced plant heights (PH) of 94-99 cm, foliage diameters (FD) of 122-128 cm, number of capitulae (NC) of 530-850, biomass per plant (BP) of 5.3 g, and biomass per square meter (BSM) of 1.3 kg. In comparison, non-elimination of weeds produced smaller yields: PH 75 cm, FD 30 cm, NC 72, BP 3.3 g, and BSM 620 g. Increasing plant spacing produced increased FD, NC, BP, and BSM, while HP remained the same. The highest BSM (2.6 kg) was produced with plant spacing of 30 cm X 30 cm and two shallow tillings. In the case of T. filifolia, the highest biomass production obtained without shallow tilling was with the plants spaced at 20 cm X 20 cm.
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Essential oils from the inflorescences of Tagetes argentina Cabr., T. terniflora H.B.K., T. laxa Cabr. and T. filifolia Lag. from Argentina were studied by GC/MS. The oils of T. argentina and T. laxa were found to be rich in (E)- and (Z)-tagetenone (
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Tetranychus urticae Koch (Acari: Tetranychidae) and Bemisia tabaci Genn. (Homoptera: Aleyrodidae) are two economically important pests of greenhouse vegetables and ornamentals. The management is commonly done based on repetitive applications of chemicals, resulting in environmental pollution and resistance in pest population.In the present study, essential oil vapours from Micromeria fruticosa L., Nepeta racemosa L. and Origanum vulgare L. (Lamiaceae) were tested for toxicities against the nymphs and/or adults of T. urticae and the adults of B. tabaci. Amounts of the essential oils applied were 2, 4, 6 and 8μl in each of the desiccators with 4 l capacity, corresponding to 0.5, 1, 1.5 and 2μl/l air. The essential oil vapours of all three plant species caused the highest mortality in 2μl/l air doses and at 120h of exposure in both of two pests’ species. In general, higher mortality was observed as the doses of essential oils and exposure period increased. T. urticae was more tolerant than B. tabaci at all doses of essential oils in all times. The data may suggest that essential oils of all three plants have potential to be used for management of T. urticae and B. tabaci pests in greenhouse conditions.
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A field experiment was conducted during 1994–95 at the Research Farm of the Central Institute of Medicinal and Aromatic Plants (CIMAP), Lucknow, India to study the yield potential of Artemisia annua planted at different times on sandy loam soil in a subtropical environment. Results revealed that the crops planted between September to December produced significantly higher herbage yield measured directly, or after drying compared with that of February planted crop. September planted crop yielded the highest amount of artemisinin. Therefore, the plants established during pre-winter (August-September) weather and allowed to grow through the entire winter synthesized and accumulated more artemisinin than plants established during early (October-November) and late (February) winter periods. The crop planted in November (or the beginning of winter) was found to be significantly superior to a crop planted in August, January or February, both in herbage production and oil yield. The September planted crop yielded relatively less oil than the November planted crop but the artemisia ketone content of the oil of the former was better. It is concluded that the artemisinin content is dependent on the weather conditions, and high yields of artemisinin do not necessarily depend on high dry matter production by the crop. Under northern Indian plains conditions, the Artemisia annua crop should be planted in September for getting higher artemisinin yield with superior quality of oil as measured by the artemisia ketone content, and in November for obtaining maximum oil yield.
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Six wild Tagetes minuta accessions were collected from different locations in Argentina and were grown in the same environment to investigate their essential oil yield and composition. Essential oil yield differed among accessions. Essential oil production of Buenos Aires and Mendoza accessions did not change between years, and Mendoza always yielded more than Buenos Aires. There was no correlation between the yield of essential oil and the total aerial biomass. Regardless of the accessions origin, dihydrotagetone, α-phellandrene, limonene, o-cymene, as well as the isomers of β-ocimene, tagetone and tagetenone were the major constituents of the essential oil. Three chemotypes were identified. Chemotypes differed in biomass production and essential oil yield of inflorescences and leaves. Leaves of the Mendoza accession were rich in dihydrotagetone as opposed to those of Buenos Aires, while the inflorescences of Mendoza accession, as well as the inflorescences and leaves of Buenos Aires have similar dihydrotagetone contents.