‘While there’s tea, there’s hope’ – Arthur Pinero (1853-1924), divulge the significant importance of tea as a beverage to humans in world. It is estimated that one-half of the population in the world consumes tea. In India, tea industry occupies a prime position among the various plantation crops due to its greater economic value, as it alone, offers employment to 20 lakhs people directly and indirectly in the country. The beverage was obtained from the leaves of tea plant, Camellia sinensis O. Kuntze (Family: Theaceae) which was introduced in India by British during 1823. The earlier records fostered the plant as a medicinal plant during the period of Shang dynasty in China and as fanap among the Assam tribes in the regions of Himalayas, during 10th century B.C (Yang et al., 2014; Yao, 1992; Zha, 1992). The novel genetic analysis methods, using chromosome number, hybridization and polyploids, scientists predicts that there is likely a single place of origin for C. sinensis O. Kuntze which includes the northern part of Burma, Yunnan and Sichuan provinces of China exclusively in the area covering high regions of South-west China, Myanmar and Northeast India (Heiss and Heiss, 2007).
Initially, tea has been considered as a drink for Lords, Kings and their descendants (Barua, 1989). Later on due to the advent of European countries and owing to development of trade, tea was taken to various parts of the world and propagated for cultivation (Figure: 1). It laid hope in South Indian planters as an alternate to coffee that held Europeans in thrall over 18th and 19th centuries (Muthiah, 1993). Currently, six types of tea are being consumed in world. Among them, black tea has been consumed traditionally, while others viz., green tea (western countries), white tea, yellow tea, (East Asia, Arabian countries), Oolong-tea (China, Taiwan) and scented tea became relatively widespread recently (Xu and Chen, 2002).
Present scenario states that more than 30 countries including India, from Georgia 430N latitude to Nelson in New Zealand 420 S latitude and from sea level to 2300 m above MSL are cultivating tea, comprising a total area of 2.77 million ha. (Yang et al., 2014).
India stands second in tea cultivating area (21%) next to China (45 %) and ranks 4th place in export. Around 5,66,660 hectares of land is under tea cultivation and their annual production was 1,267 million kg. during the year 2016. South India is the fifth largest tea producing belt which envisages 1,06,8500 ha. of land in humid Western ghats regions of Tamil Nadu (57 %), Kerala (41 %) and Karnataka (2%) (Figure: 2). The annual tea production in South India is around 234 million Kg, with 70% contribution from five regions of Tamil Nadu viz., Anamallais, Nilgiris, Kanyakumari, Madurai and Tirunelveli (Radhakrishnan and Durairaj, 2017).
In South India, tea is being cultivated by adopting two major types of farming systems such as, conventional and organic farming which are defined as,
Conventional farming refers to a method of farming in which the use of Genetically modified crops/organism’s, chemical pesticides, herbicides and chemical fertilisers are allowed (Gomiero, 2011; IFOAM, 2005).
Organic farming is a holistic production management system that avoids use of synthetic fertilizers, pesticides and genetically modified organisms, minimizes pollution of air, soil and water, and optimizes the health and productivity of interdependent communities of plants, animals and people’ (FAO, 2001).
Around 179 countries are producing certified organic products for commercial usage. The global market for organic food worth about 81.6 billion $ in 2015. India ranks 9th in terms of cultivable land under organic certification (118 mill. ha.) and stands first with the most organic producers (FiBl, 2017; Willer and Lernoud, 2017). India is bestowed with a lot of potential resources to produce organic products. In several parts of the country, the inherited tradition of organic farming is an added advantage. This holds promise for the organic producers to tap the market, which is growing steadily in the domestic market relatively to the export market. National Programme for Organic Production (NPOP) is being implemented by the Ministry of Commerce & Industry, Govt. of India for exports under the Foreign Trade Development Regulations (FTDR) Act since October 2001under the Foreign Trade and Development Act. for the improvement of organic production and to encourage the development of organic cultivation and processing (APEDA, 2016).
Around 90% of tea is being cultivated by conventional method only. Organic cultivation of tea was first initiated during 1886 in Sri Lanka. Since then, it has become wide-spread in India, Sri Lanka, China, Japan, Seychelles, Tanzania, Kenya, Malawi and Argentina. Organic farming of tea, works at grass root level preserving the reproductive and regenerative capacity of the soil, good plant nutrition, and sound soil management. It focuses on sustainability, environmental protection and animal welfare by reducing or eliminating chemical inputs such as fertilizers, pesticides and growth promoters and the use of genetically modified organisms (GMO) (Halberg et al., 2006; Yussefi, 2005). They promotes regional approaches, where both production and consumption occur within a logistically limited range.
Globally, organic tea production was 6,000 metric tons in 1999 and increased to 49,192 metric tons in 2012. The annual growth rate lies around 6%. The total production of organic tea made by India is of 0.8% by holding third place after China (1.5%) and Japan (1.8%). Domestic demand in producing countries was minimal because these teas were largely cultivated for export with 75% destined for North America, Japan and Europe. The average declared value of organic black tea from India increased to $7.60 per kilo ($3.46 per pound) in 2014 (Bolton, 2015). Some of the key players in the organic tea market include Tata Tea Limited (Tetley), Alkaloid AD Skopje (Good Nature), Twining and Company Limited, Unilever (Lipton), Organic India, Ceylon Organics Limited, The Stash Tea Company. (Tea Board India, 2016).
In India, the major contributor of organic tea originates from Darjeeling. While in South India 1.9 thousand ha. of land was under organic tea cultivation producing 3.08 million kg. of organic tea annually. Organic tea accounts for 2% of the total exports during 2015-16 (APEDA, 2016). There is an increasing awareness and demand for organic tea in world market, which was emphasized by the working group on ‘Organic Tea’ in their first inter-sessional meeting organized on September, 2012 in Washington DC, USA. Recently, the Tea Board of India had participated in BIOFACH 2017 at Nuremberg, Germany to sustain the visibility and promotion of Indian organic tea in the organic space substantively (Tea Board India, 2016).
A reasonable agriculture would do emulate its nature. In support of it, in Atharavaveda it has been stated as Bhumi Suktam and Vasudhaivakutumbakam – which means ‘the whole earth is one family’ were the most impressive and most eloquent testaments of ecological values which forms the base for modern ecology (Pant, 1996). As a part of it, “Agrobiodiversity ” which forms a fundamental feature of farming system around the world, encompasses many types of biological resources tied to agriculture, including genetic resources, live stock, soil organisms and naturally occurring species. Agro-ecosystem components and methods of farming (polycultural/monocultural, small/large scale, rainfed/irrigated, etc.) are indispensable for nutrient cycling, stability, and productivity (Acs et al., 2007; Bianchi et al., 2013;Van Diepeningen et al., 2006;).
Pests, diseases and weeds are important factors limiting the productivity and quality of tea. More than 1,000 species of insects and mites, 500 species of fungi and 250 plant species have been identified as harmful to tea plant (Chen and Chen, 1989; Pimentel et al., 2000). While, mites, thrips, scale insects, Helopeltis and caterpillars and pathogenic fungi are the most pests of foliage, shot hole borer and termites infest the stem. White grubs, nematodes ad pathogenic fungi attack roots. Weeds are problematic in new clearings, pruned fields and vacant patches of tea fields (Manning, 1948 a; Muraleedharan, 1991; Radhakrishnan and Mohan Kumar, 2014). Pest species saturation was apparently reached in the plantation crops (tea) in the age of about 35 years. (Banerjee, 1981). Organisms in such saturated ecosystems exist in complex interdependent associations such that loss of one keystone species as a result of pesticides (or other causes) can have far reaching and unpredictable effects. The loss of a keystone species results in a range of dramatic cascading effects that alters trophic dynamics, other food-web connections and may cause the extinction of other species in the community (Mills et al., 1993).
Agriculture production is treated like an industrial process in which plants assume the role of miniature factories (Heckman, 2007). Conventional agriculture is built around two basic goals: maximization of production and maximization of profit. Supplying the appropriate inputs thereby maximizing their productive efficiency, by manipulation of genes of the plant and raising various genotypes making the soil simply as a medium in which their roots are anchored (Jackson, 2007). Even though the intensification of agriculture would leave more land for nature (through farmland abandonment), the impact of intensified production on overall biodiversity was generally negative. There is extensive lack on considering ecological dynamics of agroecosystem (Barberi, 2013; Herrick, 2000).
In conventional method of farming, synthetic fertilizers and pesticides are an undeniable part. There are about 275 Pesticides registered under section 9(3) of the Insecticides Act, 1968 for use in the Country under Central Insecticides Board & Registration Committee (CIB) as on October, 2016. The annual average consumption of pesticides in the country is about 54108.2 MT, in which Tamil Nadu alone consumes 2096 MT of pesticides during 2015-16 which is 5% of total consumption of the country (FICCI, 2016). Studies reveals that pesticides applied for pest control, less than 0.1% reaches their target pests which means that more than 99.9% end up in the environment, affecting not only public health and also contaminating our resources. It disturbs the eco-system balance in our farms and as well as the general atmosphere (Kumar et al., 2013). Long-term usage of pesticide eliminates a species essential to the functioning of the entire community, or it may promote the dominance of undesired species or it may simply decrease the number and variety of species present in the community (Regan et al., 2017). This may disrupt the dynamics of the food webs in the community by breaking the existing dietary linkages between species (Jackson et al., 2010). Majority of the reports on negative impacts of pesticides against non-targeted organisms were based on laboratory/greenhouse studies.
Agricultural activities are a continuous interaction between their ecological, economical, political, social and technological dimensions (Bowen and Hall, 1952; Bruinsma, 2003). All these dimensions should be considered in an integrative manner while building future scenarios for agriculture. Environmental and agroecological research is currently focussing on understanding the cause-consequence relationships e.g. specific agricultural practices and land use and the responses at different levels of ecosystems. In addition, modelling approaches and methodologies of experimental ecology are being used in testing the impacts of agriculture on biodiversity and ecosystem. Only a few attempts have been made to build scenarios on how potential changes in agriculture would impact different aspects of the environment (Sala et al., 2000; Verburg et al., 2006).
In order to assess the impact of modern usage of pesticides, assessing the biodiversity is the first foot. Regarding the latter, insect’s form one of the key indexes in agro- ecosystem and play an important role in balance of it (Chand and Singh, 2012). They have been exposed to various environmental conditions since evolution and comprise a major diversified group in the animal kingdom occupying land, air and water. Extensive studies have been carried out in various agriculture crops. But in tea plant, mono-cultivation system is adopted, wherein the insect population has lot of chances in development of resistance and pest resurgence.
However, organic tea farming is one of the most successful agri-environmental scheme which protects the environment, indeed, there is little knowledge on proving the fact, ‘whether organic system increases the ecosystem services like pest control in tea plantations’. Based on the above perspectives the following study has been carried out in the Anamallais, which has a planting history of more than 100 years, with the initiation of tea cultivation by Carver Marsh and C.R.T. Congreve with 50 acres in Paralai. It is the second largest tea growing region in Tamil Nadu with magnificent range of hills with elevation ranges from 900 to 1600 MSL, wedged between Tamil Nadu and Kerala. The climate is of tropical wet (dry, humid), with a annual rainfall ranging from 160-300 cm and temperature rises to a maximum of 270C (May) and drops to a minimum of 50C (December). The habitat type is of Moist evergreen Montane forests (Habitat code: IM0151, as per WWF, 2001) supporting a great diversity of faunal and floral species. The soil belongs to latosols or oxisols group (USDA, 1997), deeply weathered and kaolinite clay predominates. Current scenario states that, the land under tea cultivation in Anamallais is about 12,500 ha of land which comprises 28 estates and exceeds in an annual production of 30 million Kg.
Hitherto, there are no records on the evaluation of insect population dynamics in the organic and conventional tea fields, in this landscape. Long term stable habitats like mono cultivation of tea, generally exhibit an extended species diversity, both in host plants and in phytophagous arthropods. Evaluating such habitats, reflects the area, geographic location, its nature of species richness, age of plants and the community. In recent years, several changes have been taken place in the agronomic practices, thereby contributed to the increase in tea productivity. But these changes have also magnified the pest problems. Based on the above perspectives, it is imperative that attempts are made to generate basic data on the ecology of insect species and utilize the information for resolving suitable strategies for their management in an efficient way.