eChapters

Nitrovasodilators are pharmaceutically key signalling molecule in the cardiovascular, immune and central nervous systems, and crucial steps in the regulation of NO bioavailability in health and diseases. These agents are well characterized and responsible for vasodilation by donation of nitric oxide (NO), and are principally employed for the treatment and prevention of angina pectoris, several cardiac diseases and regulation of vascular homeostasis (Carlstrom et al., 2024). NO has also been implicated in the pathology of many inflammatory diseases, including arthritis, myocarditis, colitis, and nephritis and a large number of pathologic conditions such as amyotrophic lateral sclerosis, cancer, diabetes, and neurodegenerative diseases. Several alternative strategies to increase NO signalling in the cardiovascular system have recently emerged, with promising therapeutic potential (Lundberg eta al., 2015). Nitroglycerin is commonly used in the treatment of angina pectoris because of its ability to decrease myocardial oxygen consumption. The use of nitroglycerin in the treatment of angina pectoris began not long after its original synthesis in 1847. Since then, the discovery of nitric oxide as a biological effector and better understanding of its roles in vasodilation, cell permeability, platelet function, inflammation, and other vascular processes have advanced our knowledge of the hemodynamic (mostly mediated through vasodilation of capacitance and conductance arteries) and nonhemodynamic effects of organic nitrate therapy, via both nitric oxide–dependent and –independent mechanisms (Divakaran and Loscalzo, 2017). These encompasses the identification of new pathways for enhancing NO synthase activity; ways to amplify the nitrate–nitrite–NO pathway; novel classes of NO-donating drugs; drugs that limit NO metabolism through effects on reactive oxygen species (Lundberg et al., 2015; Roy et al., 2023). Apart from the organic nitrates, direct activators of soluble guanylate cyclase, L-arginine, phosphodiesterase inhibitors and some other drugs also play critical role in vasoprotection (Gewaltig and Kojda, 2002).

Introduction

The integration of the Internet of Things (IoT) into the fisheries sector repre sents a significant advance toward modernizing an industry critical to global food security and economic stability. This chapter highlights the comprehensive exploration of the role of IoT technology in fisheries, its applications, implications and the challenges faced by fish farmers in adopting it.

Background and Context of IoT in Fisheries Sector

The fisheries industry, with its complex web of marine ecosystems and global supply chains, has long been characterized by fundamental interactions between humans and the environment. As the global population grows and consumer demand for seafood increases, the need for sustainable, efficient and technologically advanced fishing practices is becoming increasingly important (Prapti et al., 2022). This is where IoT introduces an innovative range of devices and solutions to meet the emerging demands of the sector.

Overview of IoT Applications in Fisheries

IoT technology opens up a box of possibilities in the fisheries sector. Real time monitoring of marine conditions, vessel tracking and fleet management, aquaculture optimization, supply chain management and predictive analytics are among the primary applications explored in this chapter. By analyzing these applications, we show how IoT increases the efficiency and sustainability of the fishing industry.

1. The process of directing or conducting the movement of vessel one place to another place is known as navigation.

2. Controlling the ship is known as seamanship.

3. VHF used up to 25 nautical miles.

4. Speed of sound wave 322m/sec.

5. Speed of radio wave 3x10 m/sec.

6. Navigation derived from latin word.

7. Earliest form of navigation is piloting.

8. Dead reckoning is rough method only.

9. Radio navigation also known as electronic piloting.

10. World chart produced by Gerardus Mercator.

Introduction
Antimicrobial resistance (AMR) is increasingly recognised as a “silent pandemic,” threatening global health and development. In 2019 alone, bacterial AMR was directly responsible for 1.27 million deaths and contributed to nearly 5 million more worldwide. Projections warn that by 2050, unchecked AMR could result in 10 million annual deaths and impose a staggering economic burden of USD 100 trillion. A major driver of this crisis is the indiscriminate and often prophylactic use of antibiotics in livestock production systems, which account for a majority of global antimicrobial consumption. The One Health framework—emphasising the interconnectedness of animal, human, and environmental health—offers a strategic pathway for mitigating AMR. It requires dismantling sectoral silos and fostering collaboration among veterinarians, physicians, public health authorities, food safety regulators, and environmental scientists. Against this backdrop, NDDB has positioned itself as a frontrunner in India by embedding One Health principles into large-scale field programmes. Since 2014, NDDB has progressively promoted alternative medicine for bovine mastitis control under its Mastitis Conrol Project (MCP), subsequently expanding in 2017–18 into a broader Disease Control through Alternate Methods (DCAM) project with Ethnoveterinary Medicine (EVM) as the central pillar.
Building Up: From DCAM to DISHA as One Health Strategy
Building on the successes of MCP, DCAM, and BCP, NDDB launched the Dairy Integrated Safety and Health Action (DISHA) project for 2025–2030, DISHA consolidates NDDB’s One Health strategy by combining animal health management, zoonotic disease surveillance, and food safety monitoring. Its objectives include: managing bovine cases with EVM, organising farmer awareness programmes, training veterinarians and health workers, screening cattle as well as their owner for brucellosis, and testing bulk milk samples for aflatoxins and antibiotic residues. Importantly, DISHA also addresses emerging food system contaminants such as microplastics, per- and polyfluoroalkyl substances (PFAs), Bisphenol-A (BPA) and heavy metals, thereby broadening the scope of One Health beyond infectious diseases.

Infra red (IR) spectroscopy is an analytical technique that serves both qualitativeandquantitativedetectionoforganicconstituents.NearInfraRed spectroscopy (NIRS) is actually a regression technique. Its predictions are based on correlations between spectral information (light absorption) and reference data fed to the spectroscopy. The principle of a NIRS machine is that a feedstuff is illuminated with light of a specific and known frequency (or wavelength) in the near infrared region. The chemical bonds in organic molecules absorb or emit infrared light when their vibrational state changes. In the near IR part of the spectrum, large changes in vibrational state are observed (overtones). In the near IR, ‘overtones’ are observed (larger than expected energy transitions that occur when molecules get ‘over excited’) resulting in broad, less well defined peaks.The characteristics of these peaks make quantification difficult as the areas of the peaks are difficult to determine and,typically,indirect (statistical) technique have to be applied to obtain usable data.Water and the C-H bonds absorb strongly in the near IR region,as do the N-H and O-H bonds,but most other have only a weak peak or none at all. The absorption of light by the feedstuff is then measured as thedifferencebetweentheamountoflightemittedbytheNIRSmachineand the amount of light reflected by the sample. Modern equipment typically uses monochromators, specially constructed mirrors that reflect light in a wavelength-dependent manner, thus allowing exposure of the sample to a single wavelength at a time. This allows samples to be scanned over the entire near IR region (they are also referred to as scanning instruments). However, as the monochromator relies on mechanical positioning of the mirror for its wavelength accuracy, the spectra generated are less reproducible from machine to machine.

Samples those are relatively transparent, such as most gases and liquids, can be assayed easily from the light transmitted (transmittance). For opaque solid samples, however, many problems arise. IR light can only travel through a few microns of opaque material. A few microns, however, can be very difficult to work with, especially when the non-homogeneous nature of most agricultural products is considered. Thus, the major challenge in applying IR spectroscopy to solid samples is sample presentation. For this technique, the sample is put into a cup and illuminated with IR light. This light can have three different fates; it can be reflected off the surface of the sample, it can enter the sample where it may be absorbed if it encounters a bond that matches the light’s frequency or, if it does not encounter such a bond, it can bounce back out of the sample. The light bounced back (or reflected) from the sample is captured and its intensity measured.

Abstract

Training is for improvement of a person. Training is no longer optional. In the 21st century, an organization’s capacity to effectively train its people is part of its ability to survive.  And if that capacity isn’t there, or if it is defective, then the organization itself will reveal that flaw in a number of destructive ways, including loss of bottom line profits. Needs identification will help to identify the necessary and relevant issues for proper planning and implementation. Needs identification is the first logical step to determine and justify the requirement for training in the first place. It acts as a prognosis of an organizational ailment. There are various methods and techniques to identify needs which are then categorized into four major categories : democratic, diagnostic, analytic and compliance needs. Since none of the technique is self sufficient in nature it is advisable to have a combination of techniques so as to get the true result i.e. the actual training needs. Need analysis is the next step in the training process to determine training for whom, why and what. The three major components of needs analysis are organizational/strategic analysis, task analysis and person analysis. Organizational analysis involves determining the extent to which training is congruent with the company’s business strategy and resources.

“A Message of Wisdom from Dead to Living”
Postmortem examination is systematic exposure and scientific examination of tissue and organs of an animal carcass or cadaver or dead body to determine the nature, extent and cause of death. It is an important diagnostic procedure which supports the diagnosis of a disease in an animal flock or herd. Several times the clinical diagnosis alone may not be sufficient to determine the process of disease occurrence. In such cases gross and histopathological investigations may give a valuable outlook to understand the mechanism of the disease process.
Role of necropsy examination
1) Critical necropsy examination complements the clinical medicine by providing a sure short supplement to the clinicians and students.
2) Necropsy examination pave a path for rational diagnosis of cause of death.
3) Necropsy examination helps to assess the line of treatment and diagnostic protocols followed during the illness.
4) Systemic necropsy examination helps to understand the pathogenesis of disease condition in a better manner.
5) Necropsy examination of animals died in a particular region helps to prevent the life of several animals in future.
6) Thorough necropsy examination in animals is an important tool to provide an expert advice to issue Insurance Certificate.
7) Post-mortem examination is often helpful to investigate the death of the animals counted under vetro-legal or forensic aspects.

• General Consideration

 • Post-mortem examination of large animals

 • Post-mortem examination of poultry

 • Steps in post-mortem examination

 • Writing of post-mortem report

 • Collection, preservation and dispatch of specimens for laboratory

diagnosis

• General Consideration

• Post-mortem examination of large animals

• Post-mortem examination of poultry

• Steps in post-mortem examination

• Writing of post-mortem report

• Collection, preservation and dispatch of specimens for laboratory diagnosis

General Consideration

Necropsy is examination of animal after death also known as post mortem examination. It helps in diagnosis of diseases and their control. It is said that “Necropsy is a message of wisdom from dead to living”. Necropsy include systemic examination of dead animal, recording of pathological lesions, their interpretation to make diagnosis of disease. Sometimes it is difficult to arrive any conclusion merely based on gross examination of dead animal. Then one should seek the help of laboratory examinations such as Histopathology, Microbiology, Immunology and Toxicology for confirmation.

Necrosis

Local death of tissue /cells in living body is known as necrosis, It is characterized by the followings.

• Pyknosis is condensation of chromatin material, nuclei become dark, reduced in size and deeply stained.

• Karyorrhexis is fragmentation of nucleus.

• Karyolysis is dissolution of nucleus into small fragments, basophilic granules/fragments.

• Chromatolysis is lysis of chromatin material.

• Necrobiosis is physiological cell death after completion of its function e.g. RBC after 140 days.

Necrosis is further classified into coagulative, caseative, liquifactive and fat necrosis which are different from apoptosis (Figs. 5.1 to 5.3).

A nectarine (Prunus persica var. nectarina) is a fuzz less variety of peach. The word nectarine means as sweet as nectar and this is very likely the obvious origin of the name. Though peaches and nectarines are commonly regarded as different fruits with nectarines often erroneously believed to be crossbred between peaches and plums or peach with plum skin. But it is not a cross between a peach and plum. They belong to same species as peaches. The smooth skin of peaches is a minor genetic variation. Fuzziness is a dominant trait of peaches. Occasionally when peach trees are crossed or self pollinated they produce some fruit whose seeds will grow into nectarine trees and others which will be peach trees. Nectarines will some time appear on peach trees, and peaches sometime appear on nectarine trees. It is impossible to tell which seeds from nectarine trees produce nectarine bearing trees, so commercial growers take branches which produce nectarines and graft them on to peach trees. These branches continue to produce nectarine.
 
In appearance, nectarine trees are same as peach trees, and are virtually indistinguishable from one another. Tree size and shape, leaves, and even buds look the same. Nectarines, however, are smaller and smooth skinned (ripe fruits look the same as unripe- the colour does not change significantly,

Introduction

Mangroves are the special group of plants or the ecosystem in a holistic scence on the inter-tidal coastal areas, edges of the islands and major estuarine mouths. The frequently tidal inundated forests on coastal areas, wetlands and the inter-tidal zones of sheltered bays or shore lines, estuarine mouths, sides of the tidal creeks, backwater, lagoons, marshes and mud-flats of the tropical and sub-tropical regions of the Globe are the major mangrove habitats or zones. Mangrove ecosystem form an important ecological asset and economic resources of the coastal marine environment. These mangrove ecosystem is the most productive ecosystem, which can efficiently fertilize the sea and estuarine water and also physically protect the coastal zone, estuarine mouth from frequent natural calamities and vitally serves as the breeding ground, nursery and grazing place of diverse species of fish, shrimps, prawns, crabs and vast group of other marine and off-shore species.

5.1 The Need

In spite of the considerable experience and quite a few facilities available in the country, the growth of application of isotope techniques is not commensurate with India’s size, its climatic and hydrogeological diversity and the sheer range of its water resources problems.

The situation may not be unique to India and other developing countries. Australia also appears to be facing a similar problem. A recent publication [1] says ‘the limited uptake of the method may be due to a number of factors. Until relatively recently, isotope hydrology has remained a largely academic pursuit, or measurements were the domain of national atomic energy agencies. A large fraction of information lies buried in the grey literature or in arcane technical journals. Interaction with local or regional water resources agencies has been the exception rather than the rule’

India has probably a stronger case for a more effective use of isotope techniques. A large portion of groundwater occurs in hard rocks in India. Normal hydrogeological and geophysical methods cannot fully describe such groundwater regimes to effectively plan their exploitation. It is essential to apply tracer hydrology methods, especially isotope geochemical techniques, for a comprehensive understanding of the systems. The examples of Manikaran geothermal springs, seepage studies in Salal tunnel and in some dams, given in the earlier chapters come under this category. Studies on percolation tanks in basaltic terrain and on recharge processes need isotope support.

It will not be long before we would be planning to exploit very deep ground waters (>500 m), both in the hard rock terrains of peninsular India as well as in the Ganga plains to meet our ever growing need for water. We would need good understanding of the recharge processes to these deep ground waters. Isotopes will have a large role in such investigations.

Arid zone hydrology is yet another area where the potential of isotope techniques has been effectively demonstrated for the characterization of the recharge processes, both palaeo and modern, and including the role of ancient rivers.

Introduction

• Thus "genetic enhancement" or "pre-breeding" refers to the transfer or introgression of genes or gene combinations from unadapted sources into breeding materials (FAO, 1996).

• Genetic enhancement plays an important role in utilizing unadapted and unutilized germplasm collections and creating vast genetic variability for development of productive cultivars / hybrids.

• Objective of Genetic Enhancement is broadening the genetic base and increases genetic diversity

• Gene pool – Harlan and de Wet (1971).

• Primary gene pool (GP-1): Members of this gene pool are probably in the same "species" (in conventional biological usage) and can intermate freely.

• Secondary gene pool (GP-2): Members of this pool are probably normally classified as different species than the crop species under consideration (the primary gene pool).

• Tertiary gene pool (GP-3): Members of this gene pool are more distantly related to the members of the primary gene pool. The primary and tertiary gene pools can be intermated, but gene transfer between them is impossible without the use of "rather extreme or radical measures such as embryo rescue (or embryo culture, a form of plant organ culture) induced polyploidy (chromosome doubling) bridging crosses (e.g., with members of the secondary gene pool).

What is that the grower wants to achieve while he nourishes the crop with costly fertilizer inputs? He would like to get maximum output (yield and quality) of the produce; and for the maximization of out-put the fertilizer input should be utilized by the crop to its maximum potential. Thus it is not higher fertilizer dose that decides the highest yield; but the highest efficiency in crop’s use of those fertilizers. The efficiency, yield/unit fertilizer can be enhanced by the following factors;

a) Plant roots absorbing (in-take) total quanta of applied fertilizer and minimizing the loss of applied nutrients by not having spare quantities lying around the soil profile. This is possible only if the quantum of application matches with the quantum of need.

b) Plants utilizing the absorbed nutrients for metabolic activities concurrent to absorption. This is possible only if the fertilizers are applied in times of need of the plants and not before or after. This compels the grower to know the physiological need of the nutrient during each developmental stages; which nutrient required when.

Here the grower must have a powerful tool or method to provide nutrients to the plants strictly following the above two factors. Fertigation offers an opportunity to practice nutrient inputs based on the above two factors: the grower is able to correctly decide the dose, type and time of providing the correct nutrient at precise quantity and at the required stage of plant/ crop development.

Thus the purpose of Agriculture, to maximize yield and quality of crops and minimize the costs of production while maintaining sustainability can be put into practice by fertigation. Two most important prerequisites to achieve all of these are the optimal and balanced supply of water and nutrients. Tuning of plant nutrient supply with the uptake and utilization rates by crops is essentially an art and is made doable by fertigation technology.

. Introduction Millets, once considered as humble and forgotten grains, have made a remarkable comeback owing to their numerous health benefits, sustainability, and resilience in diverse agroclimatic conditions. Millet consumption is gaining momentum globally and thus it becomes imperative to establish clear and comprehensive standards for these grains. The chapter gives an insight into the reasons why millet standards are necessary, the challenges associated with implementing such standards and advocacy for a concerted effort to promote these nutritious grains as staples in our diets.

Technology spurs Agricultural productivity through various scientific methods and innovations which is evidenced by the success of the Green revolution leading to agricultural development.

The Green Revolution arrived in India in 1968 and had a remarkable impact on the world of agriculture by increasing production yield by 2.5 times, amounting to approximately 2 billion tones, which has been noted as the world’s highest growth rate in the agriculture sector. Because of the science and technologies used in the form of

Rejuvenation of fruit trees is visionary approach to save the old senile declining trees for future sustainable quality fruit production through unique integration of invasive exhaustive operations in scientific manner and skilful management. Since unproductive and uneconomic orchards are in abundance, a large-scale uprooting and replacement with new plantations (rehabilitation) will be a long-term and expensive strategy. Therefore, research efforts have been initiated at various pioneer institutes/ SAUs to standardize. The technology for restoring the production potential of existing plantations by a technique called rejuvenation. Rejuvenation of old orchard is very vital under orchard management. Reiterative pruning and canopy re-building of perennial fruit trees is medium- term strategy requiring scientific skill and technique, for bringing back the youthful vigour with enhanced quantum of quality production in sustainable way within a time gap of three years for mango, litchi and cashew (Lal et al., 2000; Kumar, 2008), while two years for guava, aonla and pomegranate (Singh, 2007; Hiwale 2009) without any economic loss to growers. The old fruit orchards need to be rejuvenated since they show decline in yield and quality of produce. These trees/plants need to be rejuvenated which have attained a stage where they are no more profitable from the grower ’s point of view (Singh, 2007; Srivastava, 2007).

Abstract

Water scarcity and soil erosion are the two most severe problems in arid region of Gujarat, particularly in Kachchh district being entirely under hot arid climate. Present study examines need of soil and water conservation measures in Kachchh district utilizing topographical details and 34-year (1980-2013) annual rainfall data for ten rainfall gauging stations. The impact of three factors, i.e. rainfall, topography and drainage pattern, on the water scarcity and soil erosion was studied. The rainfall characteristics in the study area were explored by computing basic statistical properties, plotting rainfall bar charts and drawing box-whisker plots. Furthermore, topographic features are examined by using Google Earth image and available topographical details. Drainage characteristics and pattern are explained and usefulness of farm pond for water conservation is demonstrated.

Background The Gulf of Mannar is one of the world’s richest marine biodiversity areas, as well as the first biosphere reserve in the region. The EEZ (Exclusive Economic Zone) of this region is around 15,000 square kilometres, with commercial fishing taking place in about 5,500 square kilometres (Arnold John M. 2017). Throughout the year, both mechanised trawlers and non-mechanized vessels fish in this area (Arnold John M 2001). Crustaceans are the most key members of the benthic organism strata and have a higher nutritional value for humans, and a large number of tiny species contribute to the complexity and sustainability of tropical ecosystems. (Hendrickx 1995). The Brachyuran crab is one of them, and it dominates many estuary regions where salinity and temperatures can vary substantially on a daily basis. (Ng et al. 2008). There are around seven hundred genera and five thousand to ten thousand species of brachyuran crabs in the globe.

Though the extension education was originated as a “field approach” aimed to enhance the life quality of rural people, it has evolved into a scientific discipline that relies heavily on empirical research to develop and test its “field-oriented” approaches and methods. Since its birth, the extension research has passed through several phases and a range of research paradigms like community mobilisation, farmer participatory approaches, technology assessment and refinement, impact assessment, Information and Communication Technologies (ICTs) aided development, etc.

Negotiation is a communication and problem-solving process built on a broad foundation of skills and knowledge. It is also one of the most popular and effective means of resolving conflicts and misunderstandings. Negotiation is back and forth communication designed to reach agreement while leaving the other side intact and positive.

Basic principle, without which negotiation is impossible

Successful negotiation requires compromise from both sides. Both parties must gain something, and both parties must lose something. You must be prepared to give something up to which you believe you are entitled. You cannot expect to defeat your opponent or “win” a negotiation by either the power of your negotiating skills or the compelling force of your logic. This is not to say that good negotiating ability is irrelevant. In most cases, a range of possible outcomes exists. A skilled negotiator often can achieve a settlement near the top of the range.

6.1 Preparing for Negotiation

Introduction

When people hear the word Negotiation, they picture board meetings, lawsuits and favorable deal-makers sipping tea in a conference room. They are pictured being dressed in their expensive suits and handing dossiers to each other. In reality, we negotiate all the time. If we have to sight a negotiation, all you have to do is lift the window-pane and look out. For instance, have you ever decided where to dine with friends, or decided upon a leave and talked it out with your supervisor, or argued with your senior for a hike? These are all some common examples in our daily routine.

This family of sub-class polypetalae is represented by only single genera and three species. Members are cosmopolitan in distribution, except in very cold regions, and are favorite plants for garden pools. Nelumbo lotus are the ‘sacred lotus’ plants of the family. Indian lotus, found commonly in shallow lakes and pods, is Nelumbo nucifera. Nelumbo, genus of aquatic angiosperms belong to monogeneric family Nelumbonaceae is represented by two elemental species N. nucifera and N. lutea. The 1st fossil record available with Pleistocene epoch of Kashmir.The NBRI, Lucknow acts as a biodiversity conservation centre.
Among the few bulbous ornamentals which survive only in water, one of them is lotus.N.aureavallis, known from Eocene fossils from North Dakota, USA is an extinct species from USA. Nearly all parts are edible. Leaves are used for wrapping around other food before it is cooked. Stalks are sliced & added to salad. Flowers are cultivated for ornamental value, religious offerings, environment beautification, water purification, besides for food, Chinese traditional medicine & yield valuable perfume. Flowers recommended as cardiac tonic and used in curing diseases of liver, skin. Its dried and powdered rhizomes are used to cure piles. Due to its astringent qualities, rhizome is known for its hypoglycemic, anti-pyretic, anti-diarrheal, anti-bacterial and anti-inflammatory activity. It possesses anti-fungal activity against Aspergillus, Trichoderma, and Penicilium. Many traditional ancient medical texts report its use for skin conditions, notably ring worms & leprosy, sexually transmitted diseases such as gonorrhea and syphilis. Milky latex found in stems, leaves and flowers is used to fight bacterial infections. Lotus has been found to have 77% anti-oxidant activity. Swollen rhizome of vegetable lotus is used in culinary preparations. The roasted seeds are used as a substitute to coffee. Seeds are ground to obtain almond-flavoured flour. Seed pods (fresh or dried) are used in dry flower arrangement. Bhasinda is an underground stem i.e. rhizomes are edible as raw or cooked in northern parts of India.

Introduction

Plant Parasitic Nematodes (PPN) belonging to the kingdom Animalia are considered the most serious threat to agriculture and horticulture crops worldwide. The estimated yield loss on average is about 173 billion USD (12.3%), among which developing countries are more prone to nematode infestation (14.46%) than developed countries (8.8%). Nevertheless, these PPN aggravate the loss by forming disease complexes with other soil-borne pathogens (Jones et al., 2013). PPN gain entry onto the host roots through their secretome which secretes various kinds of proteins that are mandatory for the expression of disease symptoms in host plants. These proteins are generally called Nematode-Associated Molecular Patterns (NAMPs). The management of nematodes through synthetic nematicides paves the way for the production of commodities with toxic residues that may have severe ill effects after consumption. However, the use of resistant plants is another strategy to combat major PPN and suppress their population in soil and roots. Recent research progress has revealed the various defence mechanisms exhibited by plants against the invasion of PPN. Here we will discuss in brief about the various mechanisms followed by the host plants to recognise the invading PPNs and the resulting host immune response in response to recognition of various effector proteins of PPN.

Nematoda, a diverse animal phylum that comprises an estimated million species, inhabit very broad ranges of ecological niches throughout earth. These animals, ranging from microscopic to a meter in size, are extremely successful in adapting different environments and have different lifestyles as free-living or parasitic to plants, animals and humans. As a result, nematodes have evolved to communicate with a wide variety of organisms that they live and interact with, including microbes, plants, insects, other animals, and nematodes of the same and different species. These communications play a key role in the mutualism, parasitism, predatory and prey, host and pathogen relationships between nematodes and other organisms and are critical to the ecological fitness of nematodes (Hsueh et al., 2014)

Nematode Control

Plant parasitic nematodes can be controlled by several methods. The nematode control aims to improve growth, quality and yield by keeping the nematode population below the economical threshold level. The control measures to be adopted should be profitable and cost effective. It is essential to calculate the cost benefit ratio before adopting control measures.

The nematode control methods are

1. Regulatory (Legal) control
2. Physical control
3. Cultural control
4. Biological control
5. Chemical control

Plant parasitic nematodes can be controlled by several methods. The nematode control aims to improve growth, quality and yield by keeping the nematode population below the economical threshold level. The control measures to be adopted should be profitable and cost effective. It is essential to calculate the cost benefit ratio before adopting control measures.

Most of the plant parasitic nematodes affect the root portion of plants except Anguina spp., Aphelenchus spp., Aphelenchoides spp., Ditylenchus spp., Bursaphelenchus cocophilus and B. xylophilus. Nematodes suck the sap of the plants with the help of stylet and causes leaf discolouration, stunted growth, reduced leaf size and fruits, lesions on roots, galls, reduced root system and finally wilting.

Most of the plant parasitic nematodes affect the root portion of plants except Anguina spp., Aphelenchus spp., Aphelenchoides spp., Ditylenchus spp., Bursaphelenchus cocophilus and B. xylophilus. Nematodes suck the sap of the plants with the help of stylet and causes leaf discolouration, stunted growth, reduced leaf size and fruits, lesions on roots, galls, reduced root system and finally wilting. Symptoms of nematode diseases can be classified as

Symptoms produced by above ground feeding nematodes
Symptoms produced by below ground feeding nematodes

Future areas of emphasis for research and scholarship in nematode ecology are indicated by pressing agricultural and environmental issues, by new directions in applied nematology, and by current technological advances. Studies in nematode ecology must extend beyond observation, counting, and simple statistical analysis. Experimentation and the testing of hypotheses are needed for understanding the biological mechanisms of ecological systems. Opportunities for fruitful experimentation in nematode ecology are emerging at the ecosystem, community, population, and individual levels. Nematode ecologists will best promote their field of study by closely monitoring and participating in the advances, initiatives, developments, and directions in the larger f ield of ecology. Some major concepts in ecology have been explored including the dynamics of species interaction, the relationship between complexity and stability in ecosystems and the characterization of organisms as “r” or “K” selected (Howard Ferris, 1993). There has been some application of concepts of plant-herbivore coevolution and density-dependent regulation of populations.

In the soil environment plants are constantly exposed to a range of microorganisms which are likely to influence one another, as they occupy the same habitat. Phytonematodes are often considered as pathogens in their own right and are capable of producing a single, recognizable disease. Apart from this, they also get associated with other soil pathogens that result in the complex diseases, which are more devastating and cause huge crop losses. Phytonematodes are major predisposing factors for other potential soil pathogens, which deserve more attention. In the case of soil borne pathogens, further opportunities exist for interactions with other microorganisms occupying the same ecological niche. The significant role of nematodes in the development of diseases caused by soil borne pathogens has been demonstrated in many crops throughout the world. In many cases, such nematode–fungus disease complexes involve root-knot nematodes (Meloidogyne spp.), although several other endoparasitic (Globodera spp., Heterodera spp., Rotylenchulus spp., Pratylenchus \spp.) and ectoparasitic (Xiphinema spp., Longidorus spp.) nematodes have been associated with diseases caused by soil borne fungal pathogens (Back et al., 2002).

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. Some of the vegetables are good sources of carbohydrates (leguminous vegetables, sweet potato, potato, onion, garlic and fenugreek) proteins (peas, beans, leafy vegetables and garlic) vitamin A (carrot, tomato, drumstick, leafy vegetables), Vitamin B (peas, garlic and tomato), vitamin C (green chillies, drumstick leaves, cole crops, leafy vegetables and leaves of radish) and minerals (leafy vegetables, drumstick pods etc.). As per dietician recommendation, our daily requirement is 75-125g of green leafy vegetables, 85g of other vegetables and 85 g of roots and tubers with other food (http://AgriInfo.in).

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.

Plant parasitic nematodes are microscopic, thread like, soil-born organism, found in every conceivable environment. Severity of nematodes as plant pathogen is more a problem in tropical than temperate climate. These organisms are basically root feeders causing injury to the plants, which adversely affect the function of the root to absorb and translocate nutrients and water efficiently. This result into nutrient deficiency like symptoms, and as such nematode problems go unnoticed. Such symptoms are not corrected even after a dose of fertilizers.

Based on feeding habits, they are classified as migratory ectoparasitic, sedentary semi-endoparasitic or endoparasitic nematodes. They feed silently but constantly without killing the host producing debilitating symptoms and in the process reproducing to great numbers at the end of the crop season. Normally, nematodes complete their life cycles in a span of 20-25 days at temperature of 25-30 °C. They have a great egg laying capacity, which varies from 40-1000 eggs.

The most important nematode is root-knot nematode, Meloidogyne sp. distributed worldwide and can infest more than 2000 species of plants. Cereal cyst nematode, Heterodera avenae - an important nematode pest of wheat, barley and oat, citrus nematode, Tylenchulus semipenetrans associated with citrus dieback and slow decline, burrowing nematode, Radopholus similis causing spreading decline in plantation crops, the reniform nematode, Rotylenchulus reniformis in vegetables and cotton and the rice root nematode, Hirschmanniella spp in lowland rice are few other damaging nematodes.

Crossandra

Crossandra (Crossandra undulaefolia) is one of the important commercially grown flower crop in Tamil Nadu. In recent years there is a marked decline in the cultivation of this crop in Madurai, Dindigul, Coimbatore, Salem, Thiruvannamalai and Tiruchirappalli districts. The common problem with the crop is death of plants in patches during the second and third year. This is due to the nematode-fungal complex disease in the crop.

Investigations revealed the association of root-knot nematode, Meloidogyne spp. and the root-lesion nematode, Pratylenchus delattrei with the crop along with fungal patheogen, Fusarium solani.

Root-knot nematode

Both M. incognita and M. javanica are reported to cause damage and yield loss to the crop. The affected plants exhibit stunted growth, yellowing of leaves and also have chlorotic symptoms. The nematode in association with R. solani causes serious damage to the crop. The infested plants show root galls.

Crossandra (Crossandra undulaefolia) is one of the important commercially grown flower crop in Tamil Nadu. In recent years there is a marked decline in the cultivation of this crop in Madurai, Dindigul, Coimbatore, Salem, Thiruvannamalai and Tiruchirappalli districts. The common problem with the crop is death of plants in patches during the second and third year. This is due to the nematode-fungal complex disease in the crop.

Rice

Plant parasitic nematodes cause serious damage to rice crop. Thirty two species belonging to 13 genera were observed in association with the crop. Among them few are considered to be important. They are the rice white - tip nematode (Aphelenchoides besseyi), rice stem nematode (Ditylenchus angustus), rice root nematode (Hirschmanniella oryzae), root-knot nematode (Meloidogyne graminicola) and the cyst nematode (Heterodera oryzicola).

The white-tip nematode (Aphelenchoides besseyi)

The yield loss due to the white-tip nematode is estimated to be as much as 17.4 to 54.1 per cent. The nematode is distributed in India, Bangladesh, Sri Lanka, Japan, Indonesia, Taiwan, Former USSR, Italy, Cuba and Madagascar.

Plant parasitic nematodes cause serious damage to rice crop. Thirty two species belonging to 13 genera were observed in association with the crop. Among them few are considered to be important. They are the rice white - tip nematode (Aphelenchoides besseyi), rice stem nematode (Ditylenchus angustus), rice root nematode (Hirschmanniella oryzae), root-knot nematode
(Meloidogyne graminicola) and the cyst nematode (Heterodera oryzicola).

Introduction

Plant parasitic nematodes occur wherever plants grow. These nematodes are referred to as plant pathogenic when they cause crop losses by direct injury to roots, stems, leaves and seeds. A large number of plant parasitic nematodes have been found associated with fruit crops in all over India but pathogenisity has not been proved for all. Most of commonly occurring nematodes belong to genera Meloidogyne spp., Pratylenchus spp., Rotylenchulus spp., Hoplolaimus spp., Tylenchulus spp., Xiphinema spp., and Radopholus spp. etc. The nematodes damage the crops not only by feeding on plants but also by interacting with various other organisms like fungi, bacteria and viruses etc. Estimated overall average annual yield loss of the world’s major crops due to damage by plant parasitic nematodes was 12.3%. Estimated annual crop losses in India have been accounted to Rs. 242.1 billion. The crop losses due to nematode pests are not only in the form of reduced plant growth and yield but are also in the marketable quality of the produce.

Most of the plant parasitic-nematodes (PPNs)are worm-shaped microscopic animals. They are virtually invisible through naked eyes when present in soil or plant materials. It has been estimated that of the known nematode species, approximately 50% are free-living found in soil and fresh water, 25% are marine (found in sea water), 15% are animal parasites, and 10% are plant-parasites (Walia and Bajaj, 2004; Sasser and Freckman, 1987). Free living nematodes contribute to maintain the soil bio-dynamic system, by influencing microbial colonization of substrates and mineralization of nutrients (Neher, 2001), whereas PPNs feed on plants and reduce crop growth and yield efficiency. Among the PPNs, a few nematode species feed on aerial plant parts (leaves, stems, flowers and seeds), but the majority of feed on underground plant parts (roots, bulbs, and tubers).

Citrus (Citrus spp.)

Citrus is an important fruit crop and ranks third in area which is followed by mango and banana. They are grown in 105,396 hectares in India. Among the oranges, mandarin oranges, limes and sweet oranges are very popular while lemons, grape fruits, pummelos, sour and bitter oranges are of minor importance. The Citrus spp. are grown in larger extent in the states of Maharashtra, Karnataka, Kerala, Tamil Nadu, Andhra Pradesh, Punjab, Haryana, Rajasthan, Assam, Orissa and Bihar.

Nematode menace in citrus gardens are very much realised. In 1912 the citrus nematode, Tylenchulus semipenetrans was reported from California and found to cause ‘slow decline’ disease. More than 30 genera of plant parasitic nematodes are associated with the Citrus spp. Among them, Tylenchulus semipenetrans, Radopholus citrophilus, Meloidogyne spp. Pratylenchus spp. Xiphinema spp. and Hoplolaimus spp. are often associated with the crop.

Citrus is an important fruit crop and ranks third in area which is followed by mango and banana. They are grown in 105,396 hectares in India. Among the oranges, mandarin oranges, limes and sweet oranges are very popular while lemons, grape fruits, pummelos, sour and bitter oranges are of minor importance. The Citrus spp. are grown in larger extent in the states
of Maharashtra, Karnataka, Kerala, Tamil Nadu, Andhra Pradesh, Punjab, Haryana, Rajasthan, Assam, Orissa and Bihar.

Crop productivity is largely affected by the several factors; however, biotic stress factor is one of the major concerns. Horticultural crop productivity is low in India as compared to other countries for many reasons including pest problems. Plant parasitic nematodes is one of the potential threat for cultivation of some important crops- root knot and reniform nematodes in vegetables; burrowing nematodes in banana, spices and plantation crops; citrus nematode in citrus; cyst nematodes in potato, foliar and lesion nematodes in flowers etc.

Black Pepper

Black pepper (Piper nigrum) is indigenous to the tropical forests of Western Ghats of South India. The crop is grown in Kerala, Karnataka, Tamil Nadu, Andra Pradesh and Assam.

The root-knot nematode, Meloidogyne incognita and the burrowing nematode, Radopholus similis are important pests of this crop. The root-knot nematode infested vines show yellowing of lower leaves and the leaves loose natural luster. The yellowing of leaves gradually progresses upwards. The affected vine leaves become flaccid and wither. The infested plant root show root galls of varying sizes.

The burrowing nematode also causes serious damage to the vine. Var der Vecht (1950) first reported slow wilt in this crop due to R.similis infestation in Indonesia. The nematode in association with Fusarium and Rhizoctonia causes serious damage to the crop.

Black pepper (Piper nigrum) is indigenous to the tropical forests of Western Ghats of South India. The crop is grown in Kerala, Karnataka, Tamil Nadu, Andra Pradesh and Assam.

Potato

Potato is one of the most important vegetable crop grown in India. It thrives best in cool climate. Therefore it is a summer crop in the hills and a winter crop in plains.

Twenty seven species of nematodes have been reported on potato among them the cyst nematodes (Globodera rostochiensis and G. pallida) and the root-knot nematodes (Meloidogyne incognita, M. javanica and M. hapla) are important in India.

Cyst nematodes (G.rostochiensis and G. pallida)

In India, the cyst nematode menace on potato was first reported by Dr. Jones during 1961 from Nilgiri Hills.

Geographical distribution

The potato cyst nematode is distributed in Central, South and North America, Europe, Iceland, Western USSR and South Africa.

In India it is distributed in Nilgiri and Kodai Hills and in New Delhi.

Potato is one of the most important vegetable crop grown in India. It thrives best in cool climate. Therefore it is a summer crop in the hills and a winter crop in plains.