Tea In India Research Articles

India's Tea Export Potential: Stirring up Global Trade Opportunities

India's tea industry, a significant player in the global market, is poised for growth amidst evolving trade dynamics. This paper explores India's tea export potential by examining production, export trends, and competitiveness on a global scale. In 2022, global tea production reached 6,422 million kilograms, with China and India being the largest producers, while Kenya led in exports. India, the second-largest producer and fourth-largest exporter, shipped tea worth approximately USD 706 million, primarily to the UAE, Iraq, Russia, the USA, and the UK. Methodologically, this study utilizes a gravity model with PPML estimation to analyze India's tea exports to 173 trading partners from 2004 to 2021, addressing zero trade observations. Revealed Comparative Advantage (RCA) and Revealed Symmetric Comparative Advantage (RSCA) indices are employed to assess competitiveness, revealing an upward trend in India's comparative advantage. Transitional probabilities provide insights into shifting trade patterns, indicating significant market instability in countries like Germany and the UK. The analysis also includes estimation results highlighting the impact of GDP, geographical distance, population, and other factors on India's tea exports. Results demonstrate that India has considerable potential to expand tea exports to 118 countries, with high prospects in Uzbekistan, the USA, France, Hong Kong, and Italy. Current export strategies focus on saturated markets, underscoring the need to explore untapped regions to maximize trade opportunities. This study highlights the necessity for India to diversify its export destinations to enhance its global trade footprint and leverage its growing competitiveness in the tea sector.

Evaluating the Potential of Bacillus Isolates for Chlorpyrifos Degradation and Their Role in Tea Growth Promotion and Suppression of Pathogens.

Pesticides employed for controlling domestic and agricultural pests are among the most dangerous environmental contaminants. Nevertheless, negligent usage and a lack of technical expertise have led to the contamination and pollution of various ecological niches. The extensive utilization of the organophosphate chlorpyrifos (CPs) for insect infestation control, coupled with its detrimental effects and persistence in the ecosystem, has led to calls for its removal from contaminated sites. The study is mainly focused on degradation of CPs; using viz. Bacillus wiedmannii A3 and Bacillus cereus P14 isolated from tea rhizosphere soil having pesticide contamination in Sonitpur district, Assam, India. These two bacterial strains were able to degrade CPs in vitro within 3days. Reverse-phase HPLC analysis suggested about 96% reduction of CPs concentration upon bacterial treatment. Again, in case of A3, GC-MS analysis revealed that CPs was modified to 2-hydroxy-3,5,6-trichloropyridine and chlorpyrifos-oxon, thus finally metabolized into non-toxic products. While analyzing P14, silane, dimethyl (2,2,2-trichloroethoxy) propoxy, and 3-aminobenzoic acid, N-trimethylsilyl-, trimethylsilyl ester were identified. These compounds were subsequently transformed into non-toxic products. In addition to this, they demonstrated a significant boost of plant growth-promoting traits in both absence and presence of CPs; also showed growth development in nursery scale condition. Moreover, they functioned as biocontrol agents against Phellinus lamaensis and Colletotrichum gloeosporioides, responsible for brown root rot and anthracnose in North East India tea plantations, respectively. Thus, the pesticide-tolerant Bacilli strains A3 and P14 could be used as bioremediation of contaminated sites and also as biostimulants, and biocontrols in tea crop production.

Assessing tea plantations biophysical and biochemical characteristics in Northeast India using satellite data.

Despite advancements in using multi-temporal satellite data to assess long-term changes in Northeast India's tea plantations, a research gap exists in understanding the intricate interplay between biophysical and biochemical characteristics. Further exploration is crucial for precise, sustainable monitoring and management. In this study, satellite-derived vegetation indices and near-proximal sensor data were deployed to deduce various physico-chemical characteristics and to evaluate the health conditions of tea plantations in northeast India. The districts, such as Sonitpur, Jorhat, Sibsagar, Dibrugarh, and Tinsukia in Assam were selected, which are the major contributors to the tea industry in India. The Sentinel-2A (2022) data was processed in the Google Earth Engine (GEE) cloud platform and utilized for analyzing tea plantations biochemical and biophysical properties. Leaf chlorophyll (Cab) and nitrogen contents are determined using the Normalized Area Over Reflectance Curve (NAOC) index and flavanol contents, respectively. Biophysical and biochemical parameters of the tea assessed during the spring season (March-April) 2022 revealed that tea plantations located in Tinsukia and Dibrugarh were much healthier than the other districts in Assam which are evident from satellite-derived Enhanced Vegetation Index (EVI), Modified Soil Adjusted Vegetation Index (MSAVI), Leaf Area Index (LAI), and Fraction of Absorbed Photosynthetically Active Radiation (fPAR), including the Cab and nitrogen contents. The Cab of healthy tea plants varied from 25 to 35µg/cm2. Pearson correlation among satellite-derived Cab and nitrogen with field measurements showed R2 of 0.61-0.62 (p-value < 0.001). This study offered vital information about land alternations and tea health conditions, which can be crucial for conservation, monitoring, and management practices.

Exploring the booming tea tourist industry and unconventional tourism through the ritual of drinking tea in India

More and more individuals are realizing the need to take time away from their regular lives to recharge their bodies and minds by visiting new places. That's why we reasoned that drinking tea while on holiday would be the most significant element in promoting the growth of the tea tourism sector. We want to bring attention to how, via the medium of tastescape, the ritual of drinking tea may help one better understand the notion of unconventional tourism in India. A tastescape is a combination of physical elements, social norms, and geographical settings. One kind of nature tourism that includes visits to tea plantations is an example of a niche market. Without a question, if you're looking for a place to visit that serves excellent tea, you should make your way to India. If the right marketing campaigns are launched to attract eco-travelers, and if the necessary efforts are made to enhance the quality of the area, the Indian Tea Estates have the potential to become a leading destination for tea tourism. The novelty of this study lies in its exploration of tea tourism prospects in India and the investigation into how the fascination with tea influences the decisions of foreign tourists visiting the country. The research aims to promote travel to India so that more people may learn about and appreciate the tea culture there. Both primary and secondary sources are used in this qualitative study. Features and advertising tactics for luring tourists are described in this research. At this point, we analyze the research data and use it to inform a set of preliminary marketing strategies. The study also found that enhancing a customer's overall impression of a company is one of the most effective ways to encourage repeat business. It is difficult to advance plans to combine the tourism and tea industries due to a lack of personnel and expertise. The difficulty may be overcome if the two parties can work together to mutual benefit. Achieving future achievements will require strengthening the connection between tea and tourism, establishing collaborations, encouraging a higher degree of local engagement, and highlighting local benefits as a way of life.

Econometric Modeling for High Impact Sustainable Organic Tea Production: The Box-Jenkins Approach

India is world’s second leading tea producer, and biggest consumers in the worldwide. The main objective of this investigation is to identify the Box-Jenkins method an Autoregressive integrated moving average (ARIMA) models that can be used to make predictions the production and yield of tea in India. In this study considered the published yearly secondary data of tea production and yield in India period of 1970-71 to 2021-22. In accordance to the Sigma square, RMSE, MAPE, MAE, AIC and SIC the most appropriate models for prediction the tea production, and yield in India are ARIMA models (1, 1, 1) and (0, 1, 1). Acceptability of the selected models has been verified with the Ljung-Box test, ACF, PACF criterion, and white noise followed by residual diagnostics. Comparison between the original data series and the estimated data series in the similar manner indications that the fitted model performs good statistically and is suitable for forecasting 19 year (period of 2022-23 to 2040-41) the tea production and yield in India i.e., the models are good prediction during and beyond the forecasting period; and we have estimated that the annual amount of tea production and yield achieved in the year 2022-23 is 13500.17 lakh tonnes and 2119.73 kg/ha respectively, which will accelerate to reach 16728.34 lakh tonnes and 2444.34 kg/ha in the year 2041-41 respectively.

Assessment and health risk of fluoride from Northeast Indian tea (Camellia sinensis L.): Fixing up the maximum residue level of fluoride in tea

The tea plant is considered a strong fluoride (F-) hyperaccumulator plant. We have proposed the Maximum Residue Limit (MRL) of F- in tea based on 321 tea samples collected from 8 tea-growing regions of Northeast India. Total F- as well as water-soluble F- content was analysed through the ion selective electrode with the recovery percentage of 100–108 to ascertain the risk associated with F- towards human health. It has been observed that total F- contents (mg kg−1) in Cachar, Darjeeling, Dooars, North Bank, South Bank, Terai, Tripura, and Upper Assam ranged from 42.5 to 111.5, 16.0 to 168.0, 48.0 to 291.0, 36.5 to 314.0, 60.0 to 154.0, 26.5 to 233.5, 26 to 118 and 44 to 244, respectively. The F- content in tea infusion varied between 1.08 mg L−1 and 2.43 mg L−1 across all eight regions with a mean of 1.90 mg L−1. The average transfer of F- from made tea (processed young shoot of tea plants comprising a bud and 2 to 3 leaves) to tea infusion was 100.46%. Fluoride content in infusion was decreased with the increment of infusion number but increased gradually with continuous infusion time. The non-carcinogenic health risk was assessed. Calculated Hazard Quotient values were far below 1. The calculated and rounded MRL (300 mg kg−1) was recommended for F- in tea in India.

Non Parametric Trend Analysis of Tea Cultivation in India

With the second-largest producer and the highest consumer in the world, tea is one of the most important beverage crops in India. Considering the importance of tea industry to India’s national economy, a trend analysis of tea cultivation has been done here. Using data on the acreage, production, and productivity of tea in India from 1960 to 2021, and following a non-parametric approach Modified Mann-Kendall test has been used to detect the trend in the data. Addition to this, Sen’s slope estimator and innovative trend analysis have been performed to analyze the magnitude of trend whereas the Pettitt Mann-Whitney test has been used to detect the single change point. The findings of tests revealed that the area, production and productivity of tea in India have significantly increasing trend over the years.

Coffee and Tea Industry in India: Current Trends and Future Prospects

India has acquired an exalted status on the global tea map. The country is the second largest tea producer in the world. Interestingly, india is also the world's largest consumer of black tea with the domestic market consuming 911 million kg of tea during 2013-14.the export earnings from plantation crops like coffee and tea played a significant role in financing indian development. Production of tea reached 1,233.14 million kg in 2017-18 from 878.65 million kg in 2008-09 with a compound growth rate of 2.86 % during 2017-2018. India tea export recorded a compound growth rate of 1.22 % during 2017-2018, where import recorded a compound growth rate of 0.78 % during 2017-2018.

Toxicity analysis and biomarker response of Quinalphos Organophosphate Insecticide (QOI) on eco-friendly exotic Eudrilus eugeniae earthworm

An ever-increasing use of pesticides in agricultural fields has led to a catastrophic decline in crop quality and, ultimately soil fertility. To control various pests, quinalphos is commonly used in India's tea plantations. This study aims to investigate the effects of the Quinalphos organophosphate insecticide on the non-target beneficial organism Eudrilus eugeniae earthworms and the biomarkers that respond to its effects. Earthworm species, especially E. eugeniae, remains as the most trustworthy and well-suited model organism for conducting a wide variety of environmental studies. The median lethal concentration (LC50) was identified as 3.561µgcm-2 (contact filter paper) and 1.054mgkg-2 (artificial soil toxicity). The 5% and 10% of LC50 value 3.561µgcm-2 was exposed to earthworm to analyze the sublethal effects at pre-clitellum, clitellum, and post-clitellum segments. Specific enzymatic activities of neurotransmitter enzyme acetylcholinesterase; antioxidantenzymes such as lipid peroxidase, superoxide dismutase, and catalase; and detoxification enzymes including glutathione S transferase, reduced glutathione, carboxylesterase, and Cytochrome P450 were analyzed. Exposure of E. eugeniae earthworm to subacute exposures of pesticides caused significant alterations in these stress markers in a concentration-dependent manner. Morphological abnormalities like bulginess, coiling, and bleeding were observed after exposure of the insecticide treatments. Histological cellular disintegration, a reduced NRRT time, and an inhibited proteolytic zone were also identified in pesticide-exposed earthworms. Studies demonstrate that the organophosphate insecticide quinalphos causes acute toxicity in E. eugeniae; hence, it is suggested that non-target eco-friendly E. eugeniae earthworms may be at risk if exposed to the excessive concentrations of quinalphos organophosphate insecticide in soil.

THE ROLE OF VISUAL NARRATIVE IN ADVERTISING: DEPICTIONS OF WOMEN IN THE FRAMEWORK OF TEA CULTURE DURING INDIA'S COLONIAL PERIOD

The purpose of the article is to focus on the role of visual narratives in advertising and how women are depicted in the context of the promotion of tea culture during the colonial period of India. India is one of the oldest kingdoms in the world, and India has passed through various ages that brought new innovations, social and economic reforms. Each phase has its own impact on society, as we can see through different forms of art, literature, music, and advertising. India is a massive market for selling products, there are different categories of products available in the market, but some of the brands are centuries old. Advertising plays an important role in the promotion of products. TEA for example: before independence in the promotion of tea culture in India there were different media of advertising; promotional activities and propaganda played an important role, and the changing role of women is represented effectively in tea advertisements. There are various examples that are witness to the significant transformation in the manner where women are portrayed in the promotion of tea culture. India was experiencing the provocative impact of western culture, which reached to new horizons of creativity and aids in the presentation of Indian women in a new framework. My paper through various example focuses on the role of women in the context of promoting tea in India.

Chai as a Colonial Creation: The British Empire’s Cultivation of Tea as a Popular Taste and Habit Among South Asians

For Indians, chai, or spiced black tea, is a sign of hospitality, served within families, workplaces, and at train stations. While most Indians now perceive chai to be an essential and unquestionable part of daily life, this was not the case until the early twentieth century. While today, masala tea (or masala chai) is seen as a traditional South Asian custom, my findings suggest that the habit of drinking tea was actually thrust upon Indians through a colonial apparatus of the British Raj that utilized indentured labor, plantations, and exploitative trade practices. In this research, I deconstruct the misunderstanding that tea is native to India by gathering records of the first tea plantations and advertisements designed to popularize tea in India. I also present evidence of British establishment of tea and sugar plantations, which preceded the mass production and distribution of chai for export and internal use. Lastly, I analyze advertisements that were used in the British campaign to popularize chai in India. The tea trade exemplifies the short and long-term inequalities that resulted from British occupation in South Asia, as it was a key factor in motivating and funding colonial expansion and in solidifying colonial control. Beyond colonizing land and bodies through tea, the British succeeded in colonizing Indians’ aesthetics and taste.

Conceptualizing China's tea history in the 19th century: Incorporation into the capitalist world‐economy

AbstractRecent accounts of China's tea history in the 19th century have been presented without adequate attention to global capitalism's dynamics, despite the fact that researchers have explicitly or implicitly accepted the idea that China experienced a massive and unprecedented change in tea cultivation during this period, prompted by the penetration of capitalist logics. By analysing China's capitalist incorporation process, I show why and how tea‐growing areas in southern China drove an export‐oriented process of tea cultivation, increasing the number of seasonal workers—including Chinese tea growers migrating to British India's tea plantations—and contributing to ecological degradation and economic underdevelopment. In addition, analysis of China's incorporation process helps to investigate the relationship between China's tea industry and its early industrialization. By allowing us to examine China's tea history and the dynamics of the capitalist world‐economy in the long 19th century in tandem, the concept of China's incorporation process elicits macrolevel, global, and historical narratives of the 19th century Chinese tea history.

An Empirical Study on Forecasting Production and Price of Tea in India

Tea is a very indispensable beverage for Indian population as we rank the world’s largest consumer of black tea. Indian tea industry had been facing many downfalls for the past few years in terms of low price, excess supply, losing flavour and all this as a whole had affected the performance of the tea industry in India. With India being the second largest producer of tea globally, the production of tea in India can be subdivided into North India and South India. The current study focuses on the comparative analysis between North India, South India and India in terms of their trends in area, production, yield, export quantity, export price, auction price and auction quantity of tea. Compounded Annual growth rate (CAGR) was the tool used to find the trends of various variables. This study also focuses on the forecasting the production and auction prices of tea in India till 2023using Autoregressive Integrated Moving Average (ARIMA) model. The results of the present study areindicating that all the variables like area, production, yield, export quantity, export price, auction price and auction quantity of tea had shown a positive trend annually, except for that of North India’s export quantity. Production and auction prices were forecasted till 2023 using different ARIMA models amongst which ARIMA (1,1,0) proved to be the best fit model for study period.

Tea War: A History of Capitalism in China and India by Andrew B. Liu (review).

Reviewed by: Tea War: A History of Capitalism in China and India by Andrew B. Liu John B. Lourdusamy (bio) Tea War: A History of Capitalism in China and India By Andrew B. Liu. New Haven: Yale University Press, 2020. Pp. 360. This is an ambitious and fairly successful attempt to use the case of Chinese and Indian tea production and trade to tell yet another, different, story of capitalism. It joins the emerging literature—for instance, Sven Beckert, Empire of Cotton (Penguin Books, 2014); Prasannan Parthasarathi, Why Europe Grew Rich and Asia Did Not (Cambridge University Press, 2011); and Kenneth Pomeranz, The Great Divergence (Princeton University Press, 2000)—that challenges conventional histories of capitalism as the notion of a modernizing West pitted against a static Other steeped in tradition. The book's uniqueness lies in its enunciation of the histories of tea in India and China in a conjoint manner, unlike much scholarship in the field, which focusses not just on one of them but within it, on one geographical area or aspect/issue, such as labor or gender. Also, while being a slice of economic history, the work draws much from the history of economic thought too. From a history of technology point of view, this work rightly challenges the tendency to place disproportionate emphasis on machinery at the expense of other social and economic factors. The central argument is that India and China were not contradistinctive with the Western world vis-à-vis the emergence of capitalism but were instead constitutive of it. This argument as such is not novel, but it is enunciated very effectively using a specific commodity and its changing fate across boundaries with mutual and broader inflections. More important is the point that many of the key ideas of capitalism as embodied in classical political economy—such as production for market, practices of labor that could, in appropriate contexts, be commodified or available for exchange as general and productive labor—were already embedded in Chinese and Indian social economic set ups. The work persuasively elucidates how native intelligentsia in China and India, for all their struggle against imperialism's ills, had internalized the basic premises of classical political economic thought and saw many of their abstracted forms resonating in their own backyard, awaiting practical and full realization. This congruence informs their subsequent embrace of the basic structures of capitalism, except that in India, indigenous capital had to replace alien capital and indentured labor yielded to free labor—at least nominally—thus bringing it closer to the notion of labor as envisaged in classical political economy and as understood by elite nationalists. In the case of China, merchant capital, seen as unproductive capital, was to be replaced by more productive capital. This was because the comprador class was not directly involved in the production process—thus minimizing the possibilities of innovations in the organization of production and in machinery. [End Page 1231] In bringing out the nuances through a well-researched narrative, the work also highlights a set of important ironies. One was how the colonial state selectively interpreted political economy. On the one hand, the colonial commercial enterprises were presented as extensions of the principles of free trade, and of the benefits of modernity, to the wider world. Yet, the theory of value centered on productive and free labor was deemed inapplicable to the non-Western context, which was not yet considered ready for such treatment. The book also captures the irony of how at the heart of such a widespread global capitalist enterprise as the tea trade lay such supposedly pre-modern features like unfree and cruelly exacting forms of labor in the Indian case, and the preponderance of comprador merchant capital in the Chinese case—both of which in fact propelled the tea trade to a great extent. The author's arguments are convincing, and the special merits of telling the story of Chinese and Indian tea together—particularly highlighting the element of competition that dictated particular forms of mobilization and extraction of labor and other resources—are clear. With regard to technology, while the work is right in flagging the need to look beyond innovations in machinery, there seems to be...

Information Visualization Using Clustering and Predictive Model

This paper aims to reveal the impact of rainfall on tea export from India, an issue that remained unexplored in the existing literature. This study explores a new model to predict India's tea export more accurately that would be helpful for Indian tea planters and exporters to plan their production as well as the inventory holding for deriving maximum value from tea export. A two-stage modelling approach has been developed. Firstly, an artificial intelligence-based growing hierarchical self-organising map algorithm is employed on the monthly time series of monthly frequency spreading over April 2005 to December 2013 to segregate India's monthly tea export data series into visual clusters of recognized pattern. Further, a predictive model using support vector machine has been developed and applied to forecast the tea export and then the importance of the predictor variables of the tea export have been identified. Finally, using the appropriate measures of performance a comparative analysis has been performed for each of the model. The newness of the study pertains to the two facts revealed from the study: firstly, India's tea export is embedded of complexity and nonlinearity, which could receive a successful clustering through growing hierarchical self organizing map that would make a deeper analysis easier with a further application of rich statistical techniques. Secondly, the analysis of prediction errors and the relative importance of the predictor variables establish rainfall as one of the most significant variable in predicting India's tea export, insight that has never surfaced in the literature developed thus far.

Technical Efficiency in Small Tea Gardens of Assam

Although Assam has been the leading producer of tea in India, the small tea growers are a new phenomenon in the state. In the last four decades this sector has experienced tremendous growth. Owners of small plots in the hinterland of eastern Assam have taken to small tea cultivation. The sector has a potential to mitigate underdevelopment; but one needs to understand if there is technical inefficiency in its production. This paper affirms the presence of technical inefficiency and investigates its sources. Our research is based on primary data collected across five districts of eastern and central Assam. Stochastic frontier model has been used to ascertain technical inefficiency. Policy implications are spelled out in the end.

Assessment of genetic diversity, population structure, and phylogenetic relationships among the Northeast Indian and South Indian commercially released tea cultivars using TE-AFLP markers

Commercially cultivated tea clones from Northeast and Southern India were analyzed using TE-AFLP markers. Analysis of molecular variance (AMOVA) and structure analysis showed high genetic variance (74%) within five distinct populations. This study also confirmed that Assam and UPASI (Nilgiri) tea clones have originated from two different tea populations introduced from imported China tea seeds by British. We evaluated the genetic variation and population structure in 30 tea clones of Tea Research Association (TRA), Tocklai Experimental station (Tockali ES), Jorhat, from North Eastern India and 30 clones of United Planters Association of South India (UPASI), Valparai, from South-India, released for commercial plantations and four C. japonica accessions (Total 64) used as outliers using Three Endonuclease-AFLP markers. Six primer combinations were selected from the best 10 primer combinations that were used on a set of 24 tea accessions as a standardization procedure. Dendrograms were constructed by using Jaccard’s similarity coefficient and Unweighted Pair Group Method of Arithmetic Averages (UPGMA) clustering method based on high coefficient correlation ratios obtained. High level of genetic diversity and clustering of accessions according to morphological proximity was established with minor aberrations. Analysis of molecular variance (AMOVA) showed highest genetic variance (79%) within five populations whereas the lowest variance (21%) was found among populations. These values change to the highest 87% and the lowest 13% when Camellia japonica accessions were removed from the analysis. Population structure analyses were performed to establish the genetic diversity and exact type each clones vis-a-vis to their molecular and morphological characteristics at present. Attempts were made to find out the population structure of Northeast and Southern India tea germplasm with their relatedness to existing morphological type. These analyses confirmed that all tea clones were genetically diverse and grouped based on their morphological characteristics and geographic regions.

인도 차산업의 형성과 발전 연구

This paper discuss on the forming and development of the Indian tea industry, and the characteristics of the distinctive tea culture of the India. The Indian tea industry was started by the United Kingdom. The main reason to grow tea in their colony India was to prevent the monopoly of Chinese tea. As tea consumption grew steadily, Britain conducted an experimental study on the formation of a tea industry in India.&#x0D; Workers sincere spirit was a major factor in the Indian tea industry.&#x0D; India s tea industry has greatly developed thanks to Britain s national policy.&#x0D; These active policies and the launching of the World Expo have led to success in India s tea industry. Since then, steadily researched the production of high-quality tea by gradually spreading the production area.&#x0D; Indian workers also played a role as producers of tea, as well as consumers, using low-graded teas that could not be commodities. They created new tea called ‘Chai’ that made from Indian spices and milk. and formed Indian tea culture. Now developing Chai Tea bags, which are easily consumed by many tea companies around the world.&#x0D; The massive production of tea in India led to a decline of tea prices and the activation of tea consumption, which contributed to the consumption of cheap tea by consumers. This not only became a real factor in the spread of the Indian tea industry, but also affected exports, which led to the development of Indian tea industry worldwide.

First Report of Nigrospora Leaf Blight on Sugarcane Caused by Nigrospora sphaerica in China

HomePlant DiseaseVol. 102, No. 4First Report of Nigrospora Leaf Blight on Sugarcane Caused by Nigrospora sphaerica in China PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Nigrospora Leaf Blight on Sugarcane Caused by Nigrospora sphaerica in ChinaY. P. Cui, B. Wu, A. T. Peng, Z. L. Li, J. F. Lin, and X. B. SongY. P. CuiSearch for more papers by this author, B. WuSearch for more papers by this author, A. T. Peng†Corresponding author: A. T. Peng; E-mail: E-mail Address: [email protected]Search for more papers by this author, Z. L. LiSearch for more papers by this author, J. F. LinSearch for more papers by this author, and X. B. SongSearch for more papers by this authorAffiliationsAuthors and Affiliations Y. P. Cui , Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou, China B. Wu , Institution of Fruit Tree Research, Guangdong Academy of Agricultural Sciences and Key Laboratory of South Subtropical Fruit Biology and Genetic Resource Utilisation, Ministry of Agriculture, Guangzhou, China A. T. Peng † Z. L. Li J. F. Lin X. B. Song , Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou, China. Published Online:12 Feb 2018https://doi.org/10.1094/PDIS-07-17-1060-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Sugarcane (Saccharum spp.) is an economically important crop contributing about 80% of world sugar production, which has been widely planted in southern China, including Guangxi, Fujian, and Guangdong provinces (Raza et al. 2010). In December 2016, during our survey in the field in Guangzhou (112°57′ to 114°3′ E, 22°26′ to 23°56′ N), Guangdong, yellow and blighted symptomatic leaves were observed on symptomatic sugarcane plants, and the color of the leaf sheaths had turned red while the normal type should be white. In May 2017, this disease was also observed on sugarcane seedlings grown in the field and in the greenhouse, which were derived from seed pieces collected from symptomatic plants in the field, showing that it was a seedborne disease. To identify the etiology of this disease, symptomatic tissues were surface-sterilized using 70% ethanol for 30 s, 0.2% NaClO for 2 to 3 min, then rinsed three times in sterile water, and plated on potato dextrose agar (PDA). The fungal colonies were initially white and later turned grayish-brown with the onset of sporulation. The mycelia were separated, branched, and black to white in color. The conidia were black, single-celled, and spherical (10.2 to 15.8 μm in diameter), borne on a hyaline vesicle at the tip of each conidiophore. Genomic DNA was extracted from the cultured fungal isolate using genome extraction kit (Axygen, U.S.A.), then amplified using fungal conserved primers ITS1 (5′-TCCGTAGGTGAACCTGCGG-3′) and ITS4 (5′-TCCTCCGCTTATTGATATGC-3′) (White et al. 1990), and the amplified segments were sequenced and compared with the GenBank database through a BLAST search. The result showed that our sequence shared 100% nucleotide similarity with that from Nigrospora sphaerica (GenBank accession no. KM893076.1). According to Koch’s postulates, pathogenicity tests were conducted on 4- to 5-leaf sugarcane seedlings through both wound inoculation and non-wound inoculation methods. Plants were cultured in a growth chamber (Keli HPX-280H-A, China) at 28°C with 80% humidity. After 20 days, the leaf sheaths wound inoculated with the putative pathogen turned red, the leaves of the plants turned blighted as those observed in the field, and no symptom was observed on any plant wound- or non-wound inoculated with PDA or any plant non-wound inoculated with the putative pathogen. N. sphaerica was repeatedly isolated from symptomatic seedlings wound-inoculated with the putative pathogen but not from any plant inoculated with PDA or non-wound inoculated plants. Thus, N. sphaerica should be responsible for the Nigrospora blight we observed on the sugarcane plants. N. sphaerica has been reported to cause leaf blight on blueberry in Argentina (Wright et al. 2008), sesame in China (Zhao et al. 2014), and tea in India (Dutta et al. 2015). However, to our knowledge, this is the first report of Nigrospora leaf blight caused by N. sphaerica on sugarcane in China.

Role of host switching in the development of pesticide tolerance in Helopeltis theivora (Hemiptera: Miridae), the major pest of tea in India

SummaryThe polyphagous pest Helopeltis theivora Waterhouse (Heteroptera: Miridae) is one of the major pests of tea [Camellia sinensis, (Theaceae)]. Duranta repens (Verbenaceae), an ornamental plant producing various allelochemicals, is used in many tea estates as hedge plant. This plant was earlier reported to be an alternative host of H. theivora. To gain an insight into the pest and host–plant relationships, the present work reports studies on host-based life-cycle traits, pesticide tolerance status and levels of detoxification enzymes, such as general esterases (GEs), glutathione S-transferases (GSTs) and cytochrome P450 (CYP450). Host switching in the development of pesticide tolerance in H. theivora was evident. While comparing the biology of this pest on the primary host (tea) and the alternative host (D. repens) it was found that total developmental period was higher in the Duranta-reared population, along with significantly higher nymphal mortality and significantly less fecundity. However, there was no significant difference in incubation period, hatchability, sex ratio, pre-oviposition period and adult longevity. Susceptibility of the Duranta-reared population against quinalphos (a commonly used insecticide) was 1.41 times less than the tea-reared H. theivora population. The host-based variation in the relative susceptibility against insecticide was corroborated by differential activity of the three major xenobiotic detoxifying enzymes mentioned above. GE, GST and CYP450 activities were 2.67-fold, 1.43-fold and 1.37-fold higher in the Duranta-reared population than in the tea-reared population, possibly signifying that host switching can play a role in the development of tolerance of H. theivora against insecticides.