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Elephant foot yam, Amorphophallus campanutatus Blume (= Arum campanulatum Roxb.) belongs to the family Araceae. It is also known as elephant yam, Elephant bread, Suran, Sweet yam etc. It is a native to Tropical Asia and is found throughout the plains of the Indian sub-continent and some other parts of South East Asia and Africa growing both wild as well as cultivated.

Protected cultivation practices can be defined as a cropping technique wherein the micro environment surrounding the plant body is controlled partially or fully as
per plant need during their period of growth to maximize the yield and resource saving. Cultivation of vegetables under protective structures such as net houses has become popular in recent years (Kaur et al., 2004; Cheema et al., 2004; Singh et al., 2004).

Endowed with varied agro-climatic situations, topography and soil type, India has been a leading vegetable producing country in the world occupying the second
position in vegetable production after China with an annual production of 87.53 million tonnes from 5.86 million hectares having a share of 14.4 per cent to the world production. With commercial cultivation of as many as 61 annual and 4 perennial vegetables, India is the most diverse vegetable growing country in the world (Prakash et al., 2006).

Vegetables are the largest important constituent of our daily diet as well as high value cash crops for small, marginal and large scale growers. These are rich in proteins, vitamins, minerals and dietary fibre which are essential for our normal body functions, prevention of malnutrition and deficiency diseases. Vegetables also play key role in neutralizing the acids produced during digestion of fatty foods and also provide valuable roughages which help in movement of food in intestine.

Mites are small arthropods belonging to the sub-class Acari (also known as Acarina) and the class Arachnida. The scientific discipline devoted to the study of ticks and mites is called acarology. In soil ecosystems, mites are favored by high organic matter content and by moist conditions, wherein they actively engage in the fragmentation and mixing of organic matter (Nyle and Ray, 2009).

Biological control is a strategy which employs utilization of natural enemies to reduce the damage caused by noxious organisms to tolerable levels (De Bach and Rosen, 1991). This is the most benign method for reducing pest population in vegetable ecosystem. It opens an amicable platform for production of organic vegetables with good export value. Since the late 1950s, much of the insect control in vegetables has been based on the use of synthetic chemical insecticides.

Fresh vegetables are essential part of a healthy diet as it is an important source of vitamins, minerals and fibers. The nutritional content of vegetables varies considerably, though generally they contain little protein, fat and varying proportions of vitamins such as Vitamin A, Vitamin K and Vitamin B6, pro- vitamins, dietary minerals and carbohydrates (Woodruff, 1995; Whitaker, 2001).

To reduce the dependence on hazardous pesticides in modern agriculture, one of the most promising ways is to use insect-resistant cultivars. When available, planting resistant cultivars is one of our most effective, economically viable and environmentally sound tactics. The underlying concept of using host resistance to our advantage comes from the knowledge that most plants and animals are resistant to most potential insect attackers.

The two limbs of Arabian Sea and Bay of Bengal form parts of North Indian Ocean (NIO) on the left and right respectively. Though the Arabian Sea and the Bay of Bengal are located in the same latitudinal belt and receive the same amount of solar radiation, oceanographically these two basins exhibit remarkable differences. The reason for it is Bay of Bengal is shallow and less saline due to heavy river water discharge and Arabian Sea is deep and cold and more saline.

To understand the movement of a ocean particle, We have to consider different forces. The forces that are working are pressure gradient force, coriolis force, acceleration due to gravity and friction. The summation of all these forces is balanced by total force. As we consider unit mass, the force is equal to acceleration. The total equation is called equation of motion.

Inertial motion is typically excited when the surface currents are impulsively excited by wind forcing. If the wind were to remain steady—then the currents would eventually reach equilibrium and the time-dependent term would go to zero. But if the winds blew for a few hours and then turned off then the current would be still in motion for some time even if there would be no forcing due to turning off winds.

It is a non-accelerated frictionless horizontal motion where pressure gradient balances coriolis acceleration as shown in Fig.4.1 in both the hemispheres.

The general distribution of density in the oceans is like a two layer ocean as shown in Fig.5.1 below. A layer of more or less uniform density (nearly vertical) near the surface called as isopycnal layer and a deeper layer of higher density below with sharp increase of density is called as pycnocline.

The following scientists greatly contributed to the wind driven circulation. Out of all Ekman, Sverdrup, Stommel and Munk are most important and ever remembered for their work. So in the following pages discussion is mostly concentrated on these four scientists theories.

Wind stress at the sea surface not only causes horizontal movement of water (Ekman Net transport), but also leads to vertical motion (Ekman Pumping). This horizontal movement of water leads to the occurrence of upwelling and down welling throughout the oceans both at coastal boundaries as well as in the open ocean. As divergence of surface water causes rising, convergence of the surface water causes sinking. This rising and sinking of water are called upwelling and down welling.

Harald Ulrik Sverdrup (1888-1957), a Norwegian who began his career studying meteorology with Vilhelm Bjerknes in Oslo, was appointed director of Scripps Oceanographic Institution in 1936. His 1947 paper “Wind-driven currents in a baroclinic ocean”, which showed the link between meridional currents and the curl of the wind stress, began the modern era of dynamical oceanography and initiated large-scale modeling of ocean circulation.

While circulation is a measure of tendency of fluid rotation, vorticity is the same property of fluid for an infinitely small area.

Sverdrup’s contribution could not take into account of the western boundary and so could not explain about the circulation what happened along the west coast of the ocean. Thus his circulation, as shown in Fig.8.1c in the chapter 8, is incomplete. This problem was solved by an American Oceanographer, Henry Stommel, in 1948.

Munk (1950) built upon Sverdrup’s theory, using both the vertical and lateral eddy viscosity. Munk combined the basic features contributed by Ekman, Sverdrup and Stommel to provide the first comprehensive solution of the wind driven circulation, using the real wind field Munk included the effect of eddy viscosity in both the horizontal and the vertical dimensions (both A_h and A_z).

As water consists of two positively charged hydrogen ions and a single negatively charged oxygen ion, water is arranged as a polar molecule having positive and negative sides. This molecular polarity leads to water’s high dielectric constant (ability to withstand or balance an electric field). Water is able to dissolve many substances because the polar water molecules align to shield each ion, resisting the recombination of the ions.

The wind blows over the water, changing its surface into ripples and then to waves. Thus most of the normal waves are wind-driven. As waves grow in height, the wind pushes them along faster and higher. Sometimes waves can become unexpectedly strong and destructive. As waves enter shallow water, they become taller and slow down, eventually break on the shore.

Small amplitude wave theory was based on the premise that motions are sufficiently small to allow the free surface boundary condition to be linearized. Finite amplitude wave theories or Stokes’ higher order theories are similar as per the concept in which additional higher order terms that were neglected in the Airy’s theory are included. In general, the higher the order of the wave theory, higher will be the limiting wave height for which it would be valid.

In order to understand the generation of tides first we should understand the motions of earth with respect to sun and moon. Tides are affected by the orbit of the moon around the earth and, less so, by the earth around the sun. The orbital motion of earth with respect to sun and the orbital motion of moon with respect to earth are as shown in Fig.15.1.

The word estuary is derived from the latin word ‘aestus’ meaning tide and the adjective ‘aestuarium’ means tidal. This means low ground covered by the sea at high water.

The world population is expected to reach 9 billion by 2050. This population growth of 2 to 3 billion people over the next 30 years, combined with the changing diets, would result in a predicted increase in food demand of around 70% by 2050 (UNDESA 2009).

Insecticides are one of the key control measures to combat the insect pests for sustainable agricultural production in the world. Synthetic insecticides have been only strategy to control the resurgent and resistant insect population in of high value crops not only in India but also in the world. The advent of synthetic insecticides in the mid-20th century made the control of insect and other arthropod pests easy and much more effective, and such chemicals remain essential in modern agriculture despite their environmental issues.

The biocontrol use had almost completely disappeared due to the growth and success of the synthetic pesticide industry in the mid-1940s. The publication of Rachael Carson's 'Silent Spring' (Carson 1962) which condemned the use of agricultural pesticides and emphasized their harmful environmental effects on wildlife. Due to public outrage over this controversial book, there was a need for pesticide alternatives, which presents an opportunity for wider use of biological control (Barratt et al. 2010; Gay 2012).

Three kinds of biocontrol products are being used in India which include 1) Microbial biopesticides, 2) Plant-derived botanical pesticides, and 3) Pheromones or other natural insect growth regulators. Microbial biopesticides consist majorly of fungi, bacteria, viruses or entomopathogenic nematodes as bioactive principles.

Biopesticides are pesticides that are produced naturally by plants, animals, microbes, and other minerals. These represent less of a harm to humans and the environment than chemical insecticides. Nanotechnology is a rapidly developing scientific topic that has numerous uses in numerous industries, including agriculture. The transport of plant hormones, seed germination, water management, transfer of target genes, nano barcoding, nano sensors, and controlled release of agrichemicals are now being investigated as applications for nanotechnology in agriculture (Worrall et al. 2018).

Insecticide based plant protection in India as well as in the world resulted in wide variety of environmental and health issues. Insecticides although gave satisfactory control of target pests initially, have posed serious issues such as resistance, resurgence and residue and also contamination of water bodies, food chain leading serious ill effects in humans, mammals, soil beneficial microbiota etc. After thorough examination of scientific evidences and facts on ill effects of synthetic organic insecticides, much emphasis was given for biological control including parasitoids, predators, entomopathogens, biopesticides, microbial control etc. in order to overcome above ill effects.

A tremendous change in the Indian biopesticide industry and market has reflected on increased global trade in agricultural commodities, a healthy revolution in the consumers and stack-holders with adequate understanding on negative effective of chemical pesticides in plant protection. Currently biopesticides comprise approximately 3-5% of the Indian pesticide market, with at least 15 microbial species and 970 microbial formulations registered through the Central Insecticides Board and Registration Committee (CIBRC).

Worldwide, various biopesticides have been created and are in use, including viruses, microorganisms (bacteria, fungi, etc.), microorganism derived products, animal derived goods (pheromones, hormones, insect-specific toxins, etc.), plant derived products, and genetically modified organisms (Nicholson 2007; Erlandson 2008; Mazhabi et al. 2011; Islam and Omar 2012).

The single piece of legislation under the Indian Government that regulates the import, manufacturing, sale, transportation, distribution, and use of all varieties of insecticides, including biopesticides, is the Insecticide Act (1968). Various parameters like shelf life, cross-contamination, moisture content, and packaging are significant factors that must be addressed before a biopesticide is registered. According to Organization for Economic Co-operation and Development’s (OECD) recommendations, CIB simplified the protocols and listed the infrastructure needs for manufacturing of biopesticides. Information required to generate toxicity calls a strenuous effort.

Pest and pathogen incidence is a natural occurrence that frequently goes unreported. However, they become a concern when their spectra expand and cause significant losses. Chemical pesticides are now commonly used in agricultural techniques to lessen the impact of such severe damages. Without a question, the use of chemical pesticides has put human health, ecological health, and sustainability at danger.

Regulations should make it easier to utilise creative, long-lasting solutions, allowing for the selection of the most environmentally friendly pest management method. This can be accomplished by using expedited registration, priority registration, and a combination of comparative evaluation of pest control techniques and the substitution principle, which allows a natural pest control technique to take the place of a synthetic pesticide.

Accidental sampling: Accidental sampling as quota sampling is based upon the convenience in accessing sampling population. While quota sampling attempts comprise people possessing an obvious/visible characteristic, accidental sampling makes no such effort. Any person that comes across can be contacted for participation in the study. Collecting data are stopped when reaching the required number of respondents decided to have in the sample.

Bar chart: The bar chart or diagram is one of the ways of graphically displaying categorical data. A bar chart is identical to a histogram, except that in a bar chart the rectangles representing the various frequencies are spaced, thus indicating that the data is categorical. The bar diagram is used for variables measured on nominal or ordinal scales.

Canonical analysis: The canonical analysis can be used in the case when both measurable and non-measurable variables for the purpose of simultaneously predicting a set of dependent variables from their joint covariance with a set of independent variables.

Data Analysis: In the process of data analysis, connections or differences supporting or clashing with unique or new hypotheses should be subjected to statistical tests of significance to decide to what validity data can be said to show any conclusions.

Economy consideration: Economy consideration suggests that some tradeoff which is needed between the ideal research project and that which the budget can afford. The length of measuring tool is an important area where economic pressures are quickly felt. Even though more items give superior reliability, but in the interest of limiting the interview or observation time, the research worker is to take only a few items for his study purpose.

Factor analysis: Factor analysis is the most commonly employed multivariate procedure in the research studies when there is a systematic interdependence among a set of observed or manifest variables and the research worker is interested in finding out something more fundamental or latent which creates this commonality.

General article: A general or popular article is like a short review paper based on an area of public interest. The author can incorporate his own idea on the particular topic in this article.

Halo effect: When making an observation, some observers may be influenced to rate an individual on one aspect of the interaction by the way he was rated on another. This is similar to something that can happen in teaching when a teacher’s assessment of the performance of a student in one subject may influence his rating of that student’s performance in another.

Illuminative evaluation: The primary concern of illuminative or holistic evaluation is a description and interpretation rather than measurement and prediction of the totality of a phenomenon. It fits with the social–anthropological paradigm. The aim is to study a programme in all its aspects: how it operates, how it is influenced by various contexts, how it is applied, how those directly involved view its strengths and weaknesses, and what the experiences are of those who are affected by it.

Judgment sampling: Judgment sampling is utilized frequently during qualitative research to develop hypotheses rather than to generalize to larger populations. The research worker’s decision is used for selecting items which are considered as representative of the population in judgment sampling.

Karl Pearson’s coefficient: Karl Pearson’s coefficient of correlation (also simple correlation) is the most widely used methods of measuring the degree of relationship between two variables. This coefficient assumes that there is a linear relationship between the two variables; the two variables are causally related which means that one of the variables is independent and the other one is dependent; and a large number of independent causes are operating in both variables so as to produce a normal distribution.

Latent Structure Analysis: Latent Structure Analysis shares both of the objectives of factor analysis to extract latent factors as well as an express relationship of observed (manifest) variables with the factors as their indicators and to classify a population of respondents into guanine types. This analysis is suitable if the variables involved in the study do not possess dependency relationship and happen to be non-metric.

Matching: The matching is a technique that is used to form two groups of subjects to set up an experiment–control study to test the effectiveness of a treatment. From a pool of subjects, two subjects with identical predetermined attributes, characteristics or conditions are matched and then randomly placed in either the experimental or control group.

Narratives: The narrative technique of gathering information has even less structure than the focus group. Narratives have almost no predetermined contents except that the research worker seeks to hear the personal experience of a person with an incident or happening in his life. Essentially, the person tells his story about an incident or situation and the research worker, listen passively, occasionally encouraging the respondent.

Objective- oriented evaluation: The objective- oriented evaluation is the evaluation when it is designed to ascertain whether or not a programme or a service is achieving its objectives or goals.