Wild Marigold Research Articles

Biological Control of Potato Bacterial Wilt (Ralstonia solanacearum) Using Selected Plant Extracts

Abstract The current study evaluated the effect of methanol and water extracts of tobacco (Nicotiana tabacum L.), wild marigold (Tagetes minuta L.), and garlic (Allium sativum L.) at 50 mg·mL−1 applied at different frequencies (weekly, biweekly, and monthly) on the control of potato bacterial wilt under field conditions (two growing seasons in 2021). Weekly and biweekly application of methanol extracts from tobacco and wild marigold showed higher efficacy of biological control of the pathogen (58% and 57%) on aerial parts of potato plants than monthly application (48%). In potato tubers, weekly and biweekly application of methanol extracts caused higher biological control efficacy (75.92% and 67.39%) than monthly application (52.49%). Weekly and biweekly application of methanol extracts of tobacco and wild marigold also reduced postharvest infection and postharvest yield losses caused by potato bacterial wilt during the storage period, among other treatments. These experiments conclude that weekly or biweekly application of methanol extract from tobacco and wild marigold at 50 mg·mL−1 is a practical approach to control potato bacterial wilt in the field and storage.

Comparative study of the effects of different soluble salts on seed germination of wild marigold (Tagetes minuta L.)

Wild marigold (Tagetes minuta L.) is an important aromatic plant species with a high industrial value in its essential oil. It has spread worldwide due to its wide adaptations. However, meager information is available regarding its salt tolerance. Understanding its seed germination behavior is crucial for establishing the plant species in new saline habitats. The present work focuses on the effect of five soluble salts (CaCl2, KCl, MgCl2, Na2SO4 and NaCl) on germination velocity, salinity tolerance index and germination percentage of wild marigold. Five concentrations (0, 50, 100, 150 and 200 mM) of the salts were given in a two-factor factorial, completely randomized design (CRD). The experiment was performed in a programmed culture room at 25 ± 2 ℃ under 16 h of light (PAR: 40 µmol m−2 s−1) and 8 h dark. Findings suggest that seeds of wild marigold exhibit the highest germination percentage (GP) of more than 95% in non-saline (control) conditions. The trend of germination inhibition due to different soluble salts was in the order: Na2SO4 > KCl > NaCl > CaCl2 > MgCl2. There was a significant decrease in germination velocity (0–40.56) and salinity tolerance index (0–96.67) with the elevated levels of salinity (all applied soluble salts). The dose resulting in a 50% decrease in seed germination, i.e., IC50 (inhibition concentration value) of 79.9 mM of solute salts, was obtained for wild marigold. There are strong indications that wild marigold can tolerate moderate salinity levels and can be appraised as a salt-tolerant aromatic crop. The present study's findings will open future horizons of salt tolerance in wild marigold by identifying potential salt tolerant breeding lines.

Understanding the Effect of Different Abiotic Stresses on Wild Marigold (Tagetes minuta L.) and Role of Breeding Strategies for Developing Tolerant Lines.

Wild marigold has a growing demand for its essential oil in the flavor and fragrance industries. It can be grown over a broad range of climates, but the changing climatic conditions lead to abiotic stresses, thus restricting its productivity. Abiotic stresses at elevated levels result in the reduction of germination, growth, and essential oil quality of wild marigold leading to heterogeneous and inferior grades of “Tagetes oil.” Drought, salinity, and heavy metal stress at elevated levels have common effects in terms of ROS formation, which are the major cause of growth deterioration in wild marigold. Temperatures above 35°C inhibit seed germination. Irradiance stress reduces the biomass and essential oil yield. Waterlogging adversely affects the survival of wild marigold in high rainfall regions. The application of plant nutrients (fertilizers) modulates the biomass and essential oil yield. Wild marigold employs multiple tolerance mechanisms to cope up with the adverse effects of abiotic stresses such as the increased activity of antioxidants to maintain cellular redox homeostasis, enhanced lipid peroxidation in the cell membrane to maintain cell wall architecture, production of secondary metabolites, and accumulation of osmolytes. In this review, we tried to understand how abiotic stresses affect wild marigold. Understanding the physiological changes and biochemical characteristics of stress tolerance will contribute to the development of stress-tolerant lines of wild marigold.

气候变化情景下西藏入侵植物印加孔雀草的潜在分布预测

PDF HTML阅读 XML下载 导出引用 引用提醒 气候变化情景下西藏入侵植物印加孔雀草的潜在分布预测 DOI: 10.5846/stxb202102220494 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 农业农村部西藏自治区农业野生植物资源调查收集与监测项目（13200357） Prediction of potential distribution of the invasive plant Tagetes minuta L.(Wild Marigold) in Tibet under climate change Author: Affiliation: Fund Project: 省、部研究计划基金 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:入侵植物通常由于具有较强的适应性而能够快速繁殖扩散，影响本土物种的生长繁殖，进而威胁到当地生态安全、景观格局和农业生产等。西藏生态环境非常脆弱，一旦发生恶性物种大面积入侵，生态后果不堪设想。为了探究入侵植物印加孔雀草(Tagetes minuta L.)对西藏东南生态安全的影响趋势，基于野外实地调查数据，采用最大熵(MaxEnt)模型，应用R语言平台对模型和数据进行优化筛选，探讨影响其地理分布的主要环境因子，并模拟预测了当代及2种气候变化情景(RCP 4.5、RCP 8.5)下，其在西藏的潜在适生区分布情况。结果表明：(1)训练数据集和测试数据集的受试者工作特征曲线下的面积(AUC) 均为0.997，模拟效果较好；底层土壤酸碱度、最暖季降水量、土壤有效含水量、最暖月最高温度为影响印加孔雀草分布的主导环境因子，贡献率总和超过90%。(2)加查县、朗县是印加孔雀草分布密集区域，米林县、林芝市区、察隅县、墨脱县等地为入侵高风险地区。(3)中短期(2050年)内印加孔雀草适生面积增加明显，2070年时面积则会减少；印加孔雀草适生区在藏东南地区进一步向东北区域扩张，分布质心由当前的墨脱县域向波密县域转移。总体而言，印加孔雀草分布受土壤环境、温度和降水影响较大，气候变化将使其向西藏东部、南部扩张。研究结果对于西藏自治区制定植物入侵防控管理办法具有重要参考价值。 Abstract:Invasive plants, which could multiply and spread rapidly due to their strong adaptability, affect the growth and survival of native species, and thus threaten the local ecological security, landscape and agricultural production. Since the ecological environment of Tibet is vulnerable, once the large-scale invasion of malignant species occurs, the consequences of ecological are unimaginable. In order to investigate influence of invasive plant Tagetes minuta L. on the ecological security in southeastern Tibet in this study, the adopted MaxEnt model based on the data of field survey was used to explore the main environmental factors which contributed to its geographic distribution, and simulate the distribution of potentially suitable areas in Tibet under contemporary and two climate change scenarios (RCP 4.5, RCP 8.5) by the R language platform. The results show that:(1) both the area under the receiver operating characteristic curve (AUC) of training and test data set were 0.997, indicating that the simulation effect of the model was good. Acidity of the underlying soil, precipitation in the warmest season, available water storage capacity of the soil and max temperature of the warmest month were the main environmental factors affecting the distribution of Tagetes minuta L., and the total contribution rate was more than 90%. (2) Jiacha County and Lang County are the most densely distributed areas of Tagetes minuta L. based on the field survey. Milin County, Linzhi City, Chayu County and Motuo (Medog) County will be the high-risk areas for Tagetes minuta L. invasion based on field survey and model prediction. (3) The suitable and potential area for growth and clonization of Tagetes minuta L. would increase significantly in the middle and short term (2050s), but will decrease in the 2070s based on the model simulation. The suitable area of Tagetes minuta L. would expand furtherly in the southeast of Tibet and will expand to the northeastern area, and its distribution center would move from the current Motuo County to Bomi County. In general, the distribution of Tagetes minuta L. was greatly affected by soil environment, temperature and precipitation, and climate change would make it expand more wildly to the east and south area of Tibet. The results could help to provide theoretical support for Tibet to formulate prevention and control strategies for invasive species. 参考文献 相似文献 引证文献

Volatile Composition and Biological Activities of Tagetes (Marigold): An Overview

Tagetes commonly known as wild marigold is a plant belonging to family Asteraceae. Tagetes minuta L., commonly known as African marigold, is reputed as a source of ‘Tagetes oil’ of trade that finds an extensive use in food, flavoring, pharmaceutical, perfumery and cosmetic industry. The plant is valued for its essential oil, which is present almost in every part of the plant with little percentage in the stem and roots. The plant is native to South America and has been introduced to many countries since the time of Spanish conquest. Many species of this genus, such as T. minuta, T. erecta, T. patula, and T. tenuifolia, are cultivated as ornamental plants and studied for their medicinal properties based on the basis of their use in folk medicine. Different parts of the Tagetes species are used as remedies to treat various health problems, including dental, stomach, intestinal, emotional, and nervous disorders and muscular pain, across the world. Furthermore, these plants are studied in the field of agriculture for their fungicidal, bactericidal, and insecticidal activities. The plant occurs in temperate forests and mountain regions of the world. Himachal Pradesh, Uttrakhand and Jammu & Kashmir are the main sources of “Tagetes oil” in India where it occurs at an altitude of 1000 to 2500m AMSL. The major constituents (90-95%) of Tagetes minuta essential oil are Z-ß-ocimene, limonene (hydrocarbons) and acyclic unsaturated monoterpenes ketones, dihydrotagetone, tagetones (E, Z) and ocimenones (E, Z). The plant possess pharmacological, phytotoxic effect, antibacterial and antifungal effect, insecticidal properties, nematicidal properties, antiviral and antimicrobial activity and also find use in perfume and flavour industry. Its oil has a great demand, so the species holds a lot of potential for undertaking its large-scale cultivation.

Efficacy of Weed Management Techniques on Weed Control, Biomass Yield, and Soil Herbicide Residue in Transplanted Wild Marigold (Tagetes minuta L.) under High Rainfall Conditions of Western Himalaya

A reduced herbicide rate with hand-weeding (HW) can act as a safer and sustainable approach for weed control. A field study was conducted at CSIR-IHBT, Palampur, India during 2018 and 2019 to analyze the efficacy of herbicides in combination with manual weeding on weed control and the yield of wild marigold (Tagetes minuta L). The experiment was laid with 12 treatments, consisting of two herbicide dosages with prescribed and reduced rates (R) of pendimethalin, imazethapyr, and carfentrazone-ethyl, along with integration of reduced-rate herbicide treatments with HW. The weed population, dry matter, and the crop biomass yield had a significant effect on different weed-control treatments. Imazethapyr (R) with HW recorded a reduced weed number (9.64 m−2) and weed dry matter (13.64 g m−2) and a greater biomass yield (235.03 q ha−1). All the herbicides with integration with HW decreased the weed infestation and enhanced the biomass yield. The weed control efficacy of imazethapyr was higher than pendimethalin and carfentrazone-ethyl. Weed infestation in reduced doses of herbicides with HW was lower than in recommended doses. Herbicide residues in the soil of all herbicides at both the dosages were below the detectable limit (<0.001 μg g−1). Therefore, a reduced dose of imazethapyr integrated with HW can be prescribed to T. minuta growers as a more sustainable approach.

Elucidating the yield and quality response of Tagetes minuta L. intercropped with Zea mays L. under different spacing in the western Himalayas

Intercropping is a sustainable strategy for increasing yield with better land use over time by proper utilization of resources. This work aims to study the effects of Zea mays L. (maize)/Tagetes minuta L. (tagetes/wild marigold) cropping systems with two spacings on yield, essential oil (EO) quality, and land equivalent ratio. A factorial randomized complete block design was used to perform the analysis with five cropping pattern of maize and wild marigold in ratio 100:0, 75:25, 50:50, 25:75, 0:100 and two spacing viz., 60 and 90 cm. The findings showed that the single cropping pattern (14,291 kg ha−1) produced the maximum biomass yield of T. minuta, followed by 25:75 intercropping ratio of maize: tagetes (10,353 kg ha−1). The highest EO yield (37.57 kg ha−1) and equivalent yield (48.83 kg ha−1) of tagetes were obtained in the intercropping ratio of maize and tagetes of 25:75 and 50:50, respectively, with 60 cm spacing.Furthermore, the quality of EO increased dramatically in intercropping treatments, with the highest amounts of (Z)-β-ocimene found in the maize and tagetes ratio of 25:75 (43.66 %). The highest value of the land equivalent ratio (LER) was obtained in maize: tagetes (50:50) intercropping pattern with 90 cm spacing (1.22). According to our findings, intercropping wild marigold with maize will increase the quality of T. minuta EO while retaining tagetes yield with minimal efforts; thus, this approach can be regarded as a long-term sustainable management strategy.

Nitrogen and Sulfur Fertilization Modulates the Yield, Essential Oil and Quality Traits of Wild Marigold (Tagetes minuta L.) in the Western Himalaya.

Fertilization plays an irreplaceable role in raising crop yields; however, there are issues with unnecessary and blind use of chemical fertilizers, which raise the risk of contamination in the atmosphere. It is hypothesized that fertilization of nitrogen (N) and sulfur (S) will together improve the essential oil (EO) yield and composition of Tagetes minuta L. Thus, 2 years field experiment were carried out to evaluate the outcomes of N (0, 60, 90, and 120 kg ha–1) and S levels (0, 20, 40, and 60 kg ha–1) on T. minuta during 2018 and 2019. The growth, biomass, EO content and composition were influenced (P = 0.05) by N and S fertilization. N at 120 kg ha–1 and S at 60 kg ha–1 registered higher biomass (183.89 and 178.90 q ha–1, respectively) and EO yield (102.09 and 88.60 kg ha–1, respectively), than control. Stomatal density reduced significantly with increase of N and S levels, however, density of oil glands substantially increased with S at 40 and 60 kg ha–1. The major component of EO (Z-β-ocimene) significantly increased with 120 kg N ha–1 (42.59%) and 60 kg S ha–1 (42.35%), respectively. Available nutrients in soil and plant tissues substantially increased with N and S fertilization upto 120 and 60 kg ha–1, respectively. The highest nutrient use efficiency traits were recorded at 60 kg N ha–1 and 20 kg S ha–1. It was concluded that 120 kg N ha–1 and 40 kg S ha–1 can be proposed for T. minuta as a result of agronomic responses, which serves as a sustainable means of cropping.

Wild marigold (Tagetes minuta L.) biomass and essential oil composition modulated by weed management techniques

Weed management system plays an important role in reducing the yield losses brought by uncontrolled weeds in the agricultural production system. Moreover, the weed management studies on aromatic crops, particularly Tagetes minuta L. are not well documented. Thus a study was carried out at CSIR-Institute of Himalayan Bioresource Technology Palampur, India, during 2018 and 2019. Nine treatments of herbicides viz., pendimethalin at 1.50 kg a.i./ha (P), imazethapyr at 0.10 kg a.i./ha (I), carfentrazone-ethyl at 0.02 kg a.i./ha (C), P + HW, I + HW, C + HW (integration of all herbicide treatments with hand weeding) and hand weeding alone (HW). Lowest weed density (16.69 and 15.61 m−2), weed biomass (9.10 and 10.09 g m−2) at 75 and 105 days after sowing (DAS), respectively, and the highest total above ground biomass (17925 kg ha-1), essential oil (EO) yield (103.11 kg ha-1) was recorded in imazethapyr + hand weeding (I + HW) amongst all weed control treatments. Herbicide integrated with hand weeding lead to the reduction of the number and dry weight of weeds, with a significant increase in T. minuta total aboveground biomass and EO yield. Essential oil analysis found Z-β-ocimene, dihydrotagetone, tagetone, and ocimenone as the main constituents which were differently influenced by different weed control treatments. Treatment I + HW may therefore be recommended as weed control method for aromatic plant growers, especially in T. minuta production.

Influence of Drying Processing on Essential Oil Yield and Composition of Wild Marigold (Tagetes minuta L.) in the Western Himalayas

The effect of drying processing was investigated in wild marigold (Tagetes minuta L.) in the western Himalayas. Experiment on three drying methods (shade, sun, and oven) and seven post-harvest drying time (0, 12, 24, 36, 48, 60, and 72 h) were studied under a completely randomized design. The essential oil (EO) was obtained by hydrodistillation and was analyzed by GC and GC/MS. The moisture content of tagetes herbage was lower, while essential oil yield (g/kg dry matter) was significantly higher in sun drying for 72 h. The total area percentages of identified compounds of T. minuta essential oil were 90.5 to 94.5 % for drying method and 85.9-96.7 % for drying time. Drying methods and drying time had no significant impact on the number of EO components, as 9 chemical constituents were identified in every drying treatment. The major components were (Z)-ocimene, dihydrotagetone, (E) & (Z)-tagetone, and (E) & (Z)-tagetenone. The EO amount and the area percentage of its two main components (Z)-ocimene and dihydrotagetone were significantly influenced by the different drying methods and time. Higher proportions of (Z)-ocimene and lower proportion of dihydrotagetone in the EO of sun-dried tagetes herbage for 60 h were more pronounced. Further increase in drying time caused a greater loss in the percentage of (Z)-ocimene.

Essential Oil Content and Compositions of Naturalized Tagetes minuta L. (Wild marigold)

Tagetes minuta L. known as Muster John Henry is an annual, fragrant and naturalized plant species in Turkey. The study aimed to determine essential oil content and components of Tagetes minuta L. from the flora of Hatay. Flower and leaf parts were hydro-distilled together in the full flowering period. Essential oils were analyzed by gas chromatography-mass spectrometry. Essential oil content was found at 1.8%. Essential oil compositions that constitute 99.97% of the essential oil were revealed. Main components found as trans-β-ocimene 44.96% and berbenone 22.54%. Tagetes minuta has wide usage in perfume, food and ornamental plant industry. Further studies should perform on the cultivation of the species for national industries.

Floral biology of wild marigold (Tagetes minuta L.) and its relation to essential oil composition

Wild marigold (Tagetes minuta L.) is being commercially cultivated due to high demand of its essential oil in flavor and perfumery industry. Present study investigates pollination behavior, mechanism of pollination and floral developmental of wild marigold in to 11 stages each having distinct characteristic feature as observed by visual and light microscopy. Pollen production starts from stage-2, shape of pollen is spherical tricolpate and size varies from 0.025 - 0.031 mm. However, highest pollen availability and viability is observed at stage-6. Bilobed stigma protrude from the flowers at stage-7 indicating protandry. High bee activity is evident under open field conditions suggesting entomophilous mechanism of pollination. Based on viable seed formation and per cent germination, open field conditions are most suitable for good seed set as these conditions favor cross pollination. Despite poor seed set in self-pollinated condition germination percentage was not affected significantly. Floral biology of wild marigold suggests often cross pollinated breeding behaviour. Gas Chromatography - Mass spectrometry results showed significant variation in essential oil composition at foliage and inflorescence. The (Z)-β-ocimene (52.01 %) content was highest in inflorescence while dihydrotagetone (84.85 %) content was highest in foliage. Knowledge of pollination behavior of wild marigold is critical to decide the breeding strategies required for its improvement.

Evaluation of Some Essential Oils against Pulse Beetle (Callosobruchus chinensis L.) in Pea Seeds

The present investigations on“Evaluation of some essentials oils against pulse beetle (Callosobruchus chinensis L.) in pea seeds” were carried out during 2014-15 in the Department of Seed Science and Technology, College of Horticulture, Dr. Y.S. Parmar University of Horticulture and Forestry, Nauni–solan (H.P). The essentials oils of camphor, wild marigold, cone-bearing sage, eucalypts, lemongrass and sweet flag at 2.5 ml/kg, 1.25 ml/kg, 0.60 ml/kg and 0.30 ml /kg (v/w basis)were evaluated against C. chinensis L. infesting pea seeds. Among the six essentials oils, sweet flag possessed reasonably high and immediate toxicity resulting in 78.33 percent and 96.67 percent (2.5 ml/kg and 1.25 ml/kg doses resulted 100 % mortality) mortality in 1 and 3 days after treatment. After 7 days, cent per cent mortality was observed in seeds coated with sweet flag essential oil followed by eucalypts (85.83%) cone - bearing sage (77.50%), camphor (74.17%), lemongrass (71.66%) and wild marigold (61.67%) in descending order. After 10- days of exposure, eucalypts essential oil also resulted in complete kill even at the lowest dose (0.30ml/kg). On day -15, mortality in control had substantially increased to 67.50 percent. Egg laying was minimum on sweet flag essential oil treated pea seeds (5.25 eggs/5 females) on 7th – day of observations. In untreated pea seeds, increases in egg laying was negligible in 20 – days observations (7th day 94.08- 20th day 101.92). Progeny development from the eggs laid on pea seed treated with sweet flag essentials oil was (1 beetle).

Acylated flavonol glycosides from Tagetes minuta with antibacterial activity

Wild marigold (Tagetes minuta), a flowering plant of the family Asteraceae contains compounds of pharmaceutical and nutritional importance especially essential oils and flavonols. Identification, characterization of flavonols and determination of their antibacterial activity were major objectives of the current study. The isolation and purification of flavonols was accomplished using chromatographic techniques while structural elucidation was completed by LC–MS and NMR spectroscopy. The extracts and purified compounds were tested against various bacterial strains for antibacterial activity. A total of 19 flavonols were isolated from this species. Of these, 17 were of butanol and two of ethyl acetate extracts. Based on the concentration and purity, eight potential flavonols were selected and structurally elucidated. Four flavonols, 6-hydroxyquercetin 7-O-β-(6′′-galloylglucopyranoside; 2), 6-hydroxykaempferol 7-O-β-glucopyranoside (5), 6-hydroxykaempferol 7-O-β-(6′′-galloylglucopyranoside; 7), 6-hydroxyquercetin 7-O-β-(6′′-caffeoylglucopyranoside; 9), were identified for the first time from T. minuta. Butanol and ethyl acetate extracts of flowers and seeds showed significant antibacterial activity against Micrococcus leteus, Staphylococcus aureus, Bacillus subtilis, and Pseudomonas pikettii. Among the isolated flavonols only 1, 2, and 18 were found to possess significant antibacterial activity against M. luteus. The extracts and purified flavonols from T. minuta can be potential candidates for antibacterial drug discovery and support to ethnopharmacological use.

Role of secondary metabolites of wild marigold in suppression of Johnson grass and Sun spurge

ObjectiveTo analyze the wild marigold [(Tagetes minuta L.) (T. minuta)] leaf extract with respect to phytochemicals and allelopathic activity. MethodsThe aqueous extracts of T. minuta leaves at concentrations of 50%, 75% and 100% were prepared. Preliminary phytochemical analysis was carried out and then allelopathic effect of T. minuta on root length, shoot length, germination, fresh and dry weight of Johnson grass and Sun spurge was tested on filter paper and in soil. ResultsQualitative phytochemical analysis showed the presence of alkaloids, tannins, saponins, flavonoides and terpenoids. The higher concentrations proved to be significantly effective in reducing almost all the parameters of Sun spurge and Johnson grass in filter paper bioassay. Supplemented with the soil, all concentrations of leaf extract showed reduction in germination, root and shoot growth, fresh and dry weight of Sun spurge; however, 100% concentration significantly reduced the germination of Johnson grass. ConclusionsThis study suggests that marigold allelochemicals can be used as an integrated weed management for the production of better crop yield.

Irradiance stress and plant spacing effect on growth, biomass and quality of wild marigold (Tagetes minuta L.) – an industrial crop in western Himalaya

A study was carried out over 2 years (2009 and 2010) at the CSIR–Institute of Himalayan Bioresource Technology, Palampur, India, to investigate the effect of irradiance stress and plant spacing on growth, biomass yield, essential oil content and composition in wild marigold (Tagetes minuta L.). Four shade levels (0%, 25%, 50% and 75%) and three plant spacing (45 × 30, 45 × 45 and 60 × 45 cm) were tested as per split plot design. Heavy shading (50% and 75%) strongly reduced the total essential oil content in fresh leaves and flowers. The essential oil content of leaves, flowers and the total oil increased up to the 25% shade level and declined thereafter, with a decrease in irradiance level. Ocimene and dihydrotagetones concentration in leaf oil decreased with decrease in irradiance level; however, tagetone and ocimenone showed the reverse trend. In flower oil, ocimene decreased with an increase in shade levels. Fresh leaf, stem, flower, leaf + flower biomass, and total biomass was significantly higher in the 45 × 30 cm spacing level. Essential oil content in flowers of T. minuta grown in 25% shade at 45 × 45 and 45 × 30 cm spacing recorded significantly higher essential oil content than other treatments.

Tagetes minuta Linnaeus (Asteraceae) as a Potential New Alternative for the Mitigation of Tick Infestation

Ticks are hematophagous parasites of most vertebrate animals and can transmit various pathogens. After mosquitoes, ticks are considered the most prevalent group of ectoparasitic arthropods to transmit pathogens to humans and rank first in the transmission of agents that cause disease in animals. The primary tool used to control these ectoparasites is the use of chemical products; however, resistance to several of these chemical compounds has already been reported in various locations worldwide. Considering this reality, several studies of plant extracts have been developed aiming to identify new compounds that are able to control ticks. In this context, the essential oil of Tagetes minuta may be a promising alternative in the control of some species of ticks. T. minuta is an annual herbaceous plant belonging to the family Asteraceae and is popularly known in Brazil as “cravo-de-defunto” or wild marigold. In this review, we highlight four species of ticks that are considered important for both animal and public health in Brazil. Here, we address the methods of tick control to provide a foundation for new studies and highlight the use of phytotherapeutic T. minuta as a promising alternative in the control of these ectoparasites.

Essential oil variation of Tagetes minuta in South Africa – A chemometric approach

Tagetes minuta L., generally known as wild marigold and locally as “Kakiebos”, has been used traditionally for medicinal purposes in many countries around the world. South Africa is currently the major producer of Tagetes essential oil which is used in perfumery, cosmetics and aromatherapy. The organoleptic and therapeutic properties of an essential oil are dependent upon the chemical profile of the oil. Tagetes essential oil from India, Egypt and the United Kingdom has been reported to be highly variable. In this study, possible chemotypic variation of South African Tagetes oil was explored. Eighty-three individual plants were collected from twenty-one different localities in South Africa. Essential oils were obtained by hydrodistillation using a Clevenger-type apparatus and the oil yield obtained ranged between 0.38 and 1.52%. The essential oils were analysed by gas chromatography coupled to mass spectrometry with flame ionisation detector (GC–MS‒FID) and the major compounds accounting for >85% of the total composition were identified as: (Z)-β-ocimene (27.9–56.0%), (E)-ocimenone (7.4–37.2%), (Z)-tagetone (1.4–24.9%), dihydrotagetone (n.d.−23.4%), (Z)-ocimenone (4.5–13.9%), limonene (n.d.−6.5%) and (E)-tagetone (n.d.−3.2%). Untargeted analysis of GC–MS data using MarkerLynx® and hierarchical clustering analysis (HCA) revealed two major chemotypes. Further analysis of the two chemotypes using orthogonal projections to latent structures-discriminant analysis (OPLS-DA) identified (E)-tagetone, dihydrotagetone and (Z)-tagetone as characteristic marker constituents for chemotype 1, while chemotype 2 was characterised by (Z)-β-ocimene, (E)-ocimenone and (Z)-ocimenone.

Effect of Transplanting Date on Growth, Yield and Oil Quality of Tagetes minuta L. in Mid Hill of North -Western Himalaya

A field investigation was conducted at CSIR- Institute of Himalayan Bioresource Technology (Council of Scientific and Industrial Research), Palampur to study the effect of transplanting date on duration of phenophases, aerial biomass partitioning and essential oil productivity in wild marigold (Tagetes minuta). Tagetes crop was transplanted on six dates commencing from April 12 to June 26, 2008 at fortnightly interval. All the phenophases were hastened when the transplanting was delayed. Plant height, leaf number and branches/ plant were significantly higher in the crop which was transplanted in the month ofApril. Dry matter accumulation in different plant parts of tgetes was significantly higher in April 26 transplanted crop. In accordance with these results, herb yield was significantly higher in the crop which was transplanted on April 26. Delay in transplanting significantly decreased essential oil content. Delay in transplanting also caused variation in composition of the oil in the stem, leaf and flower. Flowers and leaves accumulated maximum essential oil. The proportion of dihydrotagetones (39.1 %) was higher in leaf oil while the presence of cis- ocimene (36.5 %) and ocimenones (41.3 %) in flower oil was recorded.

Modulation of wild marigold (Tagetes minuta L.) phenophases towards the varying temperature regimes – a field study

Field experiments were conducted during 2007 and 2008 at experimental farm of Institute of Himalayan Bioresource Technology, (CSIR) Palampur (HP), India to study the performance of wild marigold (Tagetes minuta) under changing temperature regimes over the crop growth period. The established agroclimatic indices for temperature studied elsewhere in the domain viz., relative temperature disparity (RTD), growing degree days (GDD), heliothermal units (HTU) and photothermal units (PTU) were computed for different varied dates of sowing the crop. Distinct changes in weather parameters concomitant to different sowing time consequently caused significant variation in the performance of the crop. The results indicated that the early sown crop had longest crop span (224 days) than the late sown crop (102 days), from sowing to harvesting. The mean GDD accumulation from sowing to harvest ranged from 1378 to 2518°C days HTU from 6781 to 15706°C days hour and PTU from 17400 to 33052°C days hour. Total biomass, and content and yield of essential oil were correlated with different heat units calculated during the crop growth seasons. All the agroclimatic indices had positive correlations with biomass, oil content and oil yield. Thus, these indices seem to be effective in taking into account and expressing the effect of varying ambient temperature on the duration between the phenological events for comparing the crop response to the ambient temperature between different phenological stages.