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Pesticides offer one of the best means of controlling plant diseases and pests and subsequently improving the yield. They have been used since the 19^th century. Pesticides, undoutly are poisonous and their indiscriminate use and abuse may result in ecological imbalance resulting in pest resurgence, aggravation of minor pest, pesticides resistance, environmental pollution, poising serious health hazards to man and animals. However, if used judiciously, following the guide line of Pesticide Action Network (PAN), such problems are not likely to occur, and instead improve crop yield. It is however unfortunate that many of us really lack the insight in Materia Medica of plant diseases and pests and most of the problems have occurred due to misuse and abuse of pesticides for which man is responsible and not the pesticides.

A pesticide is any material intended to prevent, destroy, repel, or mitigate any pest, which is defined as a living organism that occurs where it is not wanted or that causes damage to crops, humans, or other animals. There are many different types of pesticides, each is meant to be effective against specific pests. The term “-cide” comes from the Latin word “to kill.”

A pesticide may be referred to by several different names, which can cause confusion. The same pesticide may be referred to by a number of different names, or different pesticides may have similar names.

Advantages of Using Pesticides

Pest are an ecological problem and therefore our control strategy must be ecologically sound. Modern agriculture is a combination of both and human intervention is necessary, whether it be pulling out weeds by hand, use of pesticides or genetic engineering. Control methods evolve over time as knowledge and techniques improve. This includes the development of chemical means of control which become very important because of a number of advantages

Pest are an ecological problem and therefore our control strategy must be ecologically sound. Modern agriculture is a combination of both and human intervention is necessary, whether it be pulling out weeds by hand, use of pesticides or genetic engineering. Control methods evolve over time as knowledge and techniques improve. This includes the development of chemical means of control which become very important because of a number of advantages

There are broadly five categories of crop protection products

Insecticides: Insecticides provide protection to the crops from the insects by either killing them or by preventing their attack. They can be further classified based on their mode of action:

The Insecticides Act, 1968 and Insecticides Rules, 1971 regulate the import, registration process, manufacture, sale, transport, distribution and use of pesticides with a view to prevent risk to human beings or animals and for all connected matters, throughout India. However, recently the Union Cabinet gave its approval for the introduction of the Pesticides Management Bill with the aims of improving the quality of pesticides available to Indian farmers and introducing new, safe and efficacious pesticides. This bill will replace the existing Insecticide Act 1968.The pesticides’ regulations in India are governed by two different bodies:

Pesticide Formulation

Pesticide formulation is the process by which the pesticide is put into a form which can be easily produced, stored, transported and applied by practical methods in order to achieve a safe, convenient economic and effective method of pest control.

When a pesticide active ingredient (a.i) is manufactured, it is not in a usable form as it may not mix well with water or may be unstable. Therefore, it is mixed with other compounds to improve its effectiveness, safety, handling and storage. These other compounds can include solvents, mineral clays, stickers, wetting agents, or other adjuvant. The mixture of a.i. and inert (inactive) ingredients is called a pesticide formulation. Some formulations are premixed while others must be mixed before use. A single a.i. is often made into several formulations.

When two or more chemicals can be used in combination or mixed safely, they are said to be compatible. These combinations can be a pesticide mixed with another non-pesticide chemical, or can be two or more pesticides that are combined in the same tank mix. The reasons for combining pesticides are:

1.To control different types of pests with a single application. Often, several types of pests need to be controlled at the same time. It is generally more economical to combine the pesticides needed and make a single application.

2.To provide superior control than that obtained from one pesticide. Applicators at times combine active pesticides to kill a pest that has not been effectively controlled by either chemical alone. Many combinations are quite effective, but in most cases it is not known if the improved control is a result of an additive effect or a synergistic action of the combined chemicals on different segments of the pest population. One should always check the label prior to verify the safety and legality of mixing pesticides.

3.To increase the effectiveness of one of the chemicals. As mentioned above, this is called synergism. The material added to increase the effectiveness of the primary chemical is called a synergist. The synergist may not necessarily be pesticidal by itself, but increases the effectiveness of the pesticide with which it is combined.

Tank mixing two or more pesticides saves time and labor and reduces equipment and application costs. In some cases, however, it can alter the effectiveness of one or more of the products. Two or more pesticides are considered compatible when they can be mixed and applied in combination without adversely affecting the effectiveness or the physical and chemical properties of the mixture, or causing undesirable damage to the application site. When problems develop from mixing two or more products together, the chemicals are considered incompatible.

Incompatibility

Incompatibility is a condition that prevents pesticides from mixing together properly to form a uniform solution or suspension. The formation of flakes, crystals, or oily clumps, or severe separation is unacceptable. Such incompatible mixtures clog application equipment and limit even distribution of the active ingredient in the spray tank. This prevents good pesticide coverage. The cause of incompatibility may be the chemical nature of the materials you are mixing. Impurities in the spray tank or water also may affect compatibility. Even the order in which you mix pesticides in the spray tank is important. Sometimes the types of formulations being mixed influence compatibility. Pesticide formulations of the same type are rarely incompatible with one another because they usually contain many of the same inert ingredients and solvents. Incompatibility can be a matter of timing or placement of the pesticides. Chemical or physical incompatibility may occur between the pesticides.

The label on the pesticide container is the principal source of information about a product. The label has all the fundamental information that is required. If you need information about a pesticide, do not rely on memory as it is very easy to make a mistake. Read the label every time before using a pesticide. The lay-out of the pesticide label varies between countries. However, every label on a pesticide container from a reputable manufacturer or source will have the following information:

Pesticide Resistance

Resistance to pesticides may be defined as ‘a heritable change in the sensitivity of a pest population that is reflected in the repeated failure of a product to achieve the expected level of control when used according to the label recommendation for that pest species.

The pesticides-one amongst the most important inputs in the crop production contributed a lot to minimize the losses to crop yield. In India, on an average, 33 % of crop loss occurs due to pests and disease and runs to an estimated Rs 1.40000 crore. Pesticide is an essential in the farmers struggle to protect their crops. Pesticides consumption in India reported to 288g/ha is very low compared to global average of 900g/ha. Excessive, irrational and indiscriminate use of these pesticides causes many negative consequences, mainly the famous 3 R viz; Resistance, Resurgence and Residue aspects.

At times a pesticide application fails to reduce the levels of a pest. Usually, the farmer blames either the pesticide for this or he thinks that the pests have developed resistance. Though, the usual causes of poor results with an application of a genuine pesticide from a reputable source are:

Pesticide poisoning occurs when a pesticide enters the body and interferes with the vital systems of the body. Symptoms can begin anything from 1/2 hour to 24 hours after exposure. The typical symptoms and signs of pesticide poisoning are:

Pesticides can cause three types of harmful effects – Acute, Delayed and Allergic.

Acute effects: Are those that occur immediately after the exposure, within minutes or hours.

Definition

Adjuvants are chemicals incorporated in a pesticide formulation or added to the tank mix, to increase effectiveness and safety. They generally have no effect on pests in themselves.

There is a common practice of using the terms spurious, counterfeit, misbranded, illegal, sub-standard and others interchangeably and this often creates confusion among scientist, industrialist and extension officer. Spurious and counterfeit pesticides are the two major words used to describe all kind of anomalies in the pesticides. Hence, there is a need to have a clear understanding of these and differences between them.

Environmental protection Agency (EPA)has established category of pesticides called “Reduced Risk” pesticides to encourage the development, registration and use of products which could result in reduced risks to human health and the environment. New Generation pesticides are considered for “Reduced Risk” status if they have at least one or more of the following status: low risk to human health, low toxicity to non target organisms, low potential to contaminate ground water, surface water or other valued environmental resources and have the potential to expand the adoption and effectiveness of IPM.

Strobilurins are a group of chemical compounds used in agriculture as fungicides. They are part of the larger group of QoI inhibitors, which act to inhibit the respiratory chain at the level of Complex III.Some common Strobilurins are azoxystrobin, kresoxim-methyl, picoxystrobin, fluoxastrobin,oryzastrobin, dimoxystrobin, pyraclostrobin and trifloxystrobin. Strobilurins represented a major development in fungus-based fungicides. They were extracted from the fungus Strobilurus tenacellus. They have a suppressive effect on other fungi, reducing competition for nutrients; theyinhibit electron transfer inmitochondria,disrupting energy metabolism and preventing growth of the target fungi. Strobilurins are miracle fungicides ever developed with novel mode of action & mobility that qualifies the Unique New Generation Fungicides controlling Pathogen from diverse class.

Definition

“Biological pesticides”, or “Biopesticides” as the name suggests, are naturally occurring substances that biologically control harmful pests, especially among field crops. These are naturally produced bio chemical materials basically non-toxic to the environment that can be employed in pest control. Biopesticides could mean living organisms (bacteria, virus, and algae), their products (biochemicals produced by them) and also plant byproducts. Biopesticides offer an ecologically effective solution to the harmful effects of synthetic pesticides.

Pesticide Toxicity

Chemical tactics to manage pests can include many types of compounds. Some merely repel or confuse pests. Some interfere with weed photosynthesis, insect molting processes or development in some way. Others, including some botanical and most conventional insecticides are broadly toxic to living systems. The term pesticide literally means “pest killer". Generally speaking, when using pesticides, we are trying to garner the advantages of using pesticides while minimizing the risk to humans and other non-target organisms. Risk to humans of pesticide use is often described as:

Pesticides sustain food production and control disease and pests. They are vital for crop production and instrumental in continuous increase in food production. The consumption of pesticide in India is one of the lowest in the world. India uses a low amount of 0.5 kg/hectare pesticide compared to 7.0 kg/ hectare by USA, 2.5 kg/hectare by Europe, 12 kg/hectare by Japan and 6.6 kg/ hectare by Korea. However, despite the low consumption of pesticides, India has more problem of pesticide residues vis-a-vis other countries and these have entered into food products and underground water because of

Before applying fungicides in field at large areas, it is required to be thoroughly investigated under laboratory conditions for its efficacy on pathogen, subjected. Basic methods of testing these chemicals against subjected pathogen, under laboratory conditions are described here.

1. Poisoned Food Technique

Principle

The principle involved in this technique is to poison the medium with fungicides and then allow a teat fungus to grow on such medium. The test may be conducted both on solid and liquid medium.

1. Bordeaux Mixture

It was invented in the Bordeaux region of France by PM Millardet (1982).

Also called Bordo Mix.

Mixture of Copper sulfate (CuSO₄), Slaked lime and Water.

It is known locally in France as Bouillie Bordelaise.

Antibiotics are substances which are produced by micro-organisms and which act against micro-organisms. It is also defined as secondary metabolites produced by microorganism, which inhibits the growth of another microorganism. Most antibiotics known uptill now are products of actinomycetes and some are from fungi and bacteria. The use of the antibiotics in managing plant diseases, particlulaty the disease caused by bacteria, mycoplasma and ricketsia, is well demonstrated and are thought to be effective means because of their selective action directed towards causal agents not to the infected host. The mode of action of the antibiotics varies depending on site of action which in turn detrmines their specificity towards given target host (Table 12). Some time mixture of antibiotics are in practice in managing the diseases to reduce delay the chances of resistance development against a particular antibiotic by the causal agent. The most useful antibiotic mixture is streptocycline, which contains streptomycin and tetracycline.

The behavior of pesticides is dependent on many factors, so be sure to consider everything from light and temperature to moisture and pH and recognize that all the factors will impact the active ingredient. Here is some information on these topics, and others, which will improve pest management success.

1.Identification: The first step to disease and pest management success is the proper identification of the insect, disease or weed pest. Without identification of the pest, controls may be misused or improperly timed.

2.Time of Application: Time of application of pesticides plays major role in optimizing pesticidal performance. Early morning or late afternoon are the best times to spray. Dust formulations should be apply in early morning hours (6 am).In the case of foliar spray, it should be done in morning hours between 8 am to 11 am. Avoid spraying during the heat of the day.

3.Water Quality and pH: Primary factors important in water quality are pH and alkalinity (bicarbonates). Most of the pesticides show high efficiency in slightly acidic to slightly basic water pH (i.e. 6.5 to 7.5). Many water sources in alkaline pH (<7.0). Alkali pH (7.5>) is always harmful for pesticides. High pH levels are responsible for alkaline hydrolysis, a process that breaks down the active ingredient in many insecticides, fungicides and herbicides.Add a buffer agent to lower spray solution to a pH of 5.5-6.5. This will give better initial knockdown and longer residual action.

The Effectiveness of a Pesticide in Controlling a Disease and Pest Depends on

Using the right pesticide for the target disease & pest.

Applying the pesticide at the right time.

Applying the pesticide in the right amount.

Applying the pesticide to the right place.

Sprayer is an equipment in which the spray fluid is broken up into fine droplets and ejected under pressure. Actually, the function of the sprayer is to provide the spray fluid with some energy so that it can be broken into fine droplets through the nozzle and propelled to the target. The energy can be produced manually or with the help of any other source of power. There are a variety of sprayers.

Type of Sprayers: There are a variety of sprayers.

Pesticide Dusting

The dusting powders are low concentration ready to use type, dry formulations containing 2 to 10% pesticide. The inert material or dry diluents is talc, soapstone, attapulgite, etc. and it is non toxic. The sulphur dust is not diluted with inert material.

Spraying nozzle is a device for emitting spray liquid, breaking it up into small droplets and throwing the droplets away from the nozzle orifice. Different designs of nozzle are used to produce appropriate droplet size spectrum. In order to break the liquid into droplets energy is needed. The spray nozzles therefore are classified as:

Majority of the pesticides are applied as sprays. The liquid formulations of pesticide either diluted or directly are applied in small drops to the crop by different types of sprayers. Generally the wettable powder, EC formulations are diluted suitably with water which is a common carrier of pesticides. However, in few cases oil is used as carrier of pesticides.

Any sprayer nozzle essentially breaks the liquid into small droplets and throws them. All nozzles in the field produce rangesof droplets of different size called spray spectrum. The hydraulic nozzles have wide range of size of droplets whereas the rotary nozzles have narrow range. Adroplet of 400 µm diameter is 1000 times bigger in volume than a droplet of 40 µm. The volume of spherical droplets can be worked out as 4/3 µr3. So if the droplet size of aspraying system could be reduced to half, then there will be 8 fold increases in the number of droplets and the coverage will also increase.

i) Common Maintenance

Clean outer surface with brush or cotton waste by using plenty of water or kerosene oil.

Oil the moving or rubbing surfaces of parts with lubricating oil or grease.

Filter the chemical solution/ fuel oil mixture while pouring into the tanks. Make the caps or lids leak-proof with gaskets.

Flush the equipment with clean water to wash inside parts of containers, tubes and nozzles to be free from chemicals.

The objective of correct pesticide application cannot be achieved without good quality Plant Protection Equipment. A sound designed machine shall be proficient as far as pesticide distribution and delivery to the target in minimum time with least wastages is concerned. Hence, the machines should be tested to ascertain that they are:

Calibration is the process of measuring and adjusting the amount of pesticide your equipment applies or delivers to a specific area. The purpose of calibration is to ensure your equipment is applying the correct amount of material uniformly over a given area.

Equipment is manufactured to be adjustable. Charts or tables may be provided to assist the operator in making adjustments to the settings. These recommended settings, however, are only approximate and may not be appropriate for all situations. Therefore, your equipment must be calibrated periodically. This depends on the type of equipment and the frequency of use. The application rate of the sprayer is affected by travel speed, nozzle size, and sprayer pressure. Equipment is calibrated by making a trial run on some premeasured area and measuring the output. For example, using a hand-held sprayer, spray a premeasured test area with water using the same pressure and techniques (i.e., travel speed and equipment) you would use when applying the pesticide. After spraying the test area, determine how much water was used. This volume can then be used to calculate the amount of water and pesticide needed to cover the intended application area.

The time invested in calibrating your equipment is time well spent. Accurate calibration to determine the application rate under your operating conditions is important for cost, efficiency and safety.

Solid formulations such as dust, wettable powder or granules, the active ingredient is mixed with inert material. The concentration is expressed as:

Active ingredient (%) in the total weight of commercial product.

Effective application of pesticides depends on many factors. One of the more important is to correctly calculate the amount of material needed. Unless you have the correct amount of pesticide in your tank mix, even a correctly calibrated sprayer can apply the wrong rate.

Manufacturers provide application rate instructions on every pesticide label. Due to the variety of ways in which these recommendations are stated (such as lbs. of active ingredient (a.i.) per acre, lbs. of formulation per 100 gal. of spray, or ozs, of a.i. per 1,000 sq. ft.) it is often necessary to adapt the recommendations to different areas and volumes, or even other units. Sometimes the amount of active ingredient must be converted to the amount of actual product. This process can be very confusing.

A. Purchase

a)Do not purchase leaking containers, loose, unsealed or torn bags.

b)Do not purchase pesticides without proper/approved labels.

c)Purchase only just required quantity e.g. 100, 250, 500 or 1000 g/ml for single application in specified area.

Insect Control and Insecticides

Control Tips

Practicing Integrated Pest Management can significantly reduce the amount of insecticides needed to control many insect problems.

Broad-spectrum insecticides are effective against all insects, even the good ones. Other insecticides target certain insects. Using a targeted insecticide minimizes the risk to beneficial or non-target insects.

Some insecticides work immediately to kill insects while others may need some time to take effect.

Using more than one insecticide product in the same location can increase or decrease each one’s effectiveness. It may also result in a greater risk to health and/or the environment.

Insect growth regulators like pyriproxyfen and methoprene do not kill insects; they make it impossible for exposed insects to molt (grow) or lay eggs properly.

Insecticidal baits can be used instead of spraying large areas, especially for social insects like ants. This can decrease the risk of exposure, but remember to place baits where children and pets won’t have access.

Proper selection of a fungicide and its application at the correct dose and the proper time are highly essential for the management of plant diseases. The basic requirement of an application method is that it delivers the fungicide to the site where the active compound will prevent the fungus damaging the plant. The fungicidal application varies according to the nature of the host part diseased and nature of survival and spread of the pathogen. The method which are commonly adopted in the application of the fungicides are discussed.

1.Soil treatment

2.Seed treatment

3.Foliar or vegetative application

Definition

Seed treatment is the process by which seeds are treated with physical, chemical or biological agents to prevent the infection of seedlings and the subsequent development of the crops.

Advantages of Seed Treatments

Increased seed germination.

Ensures uniform seedling emergence.

Protect seeds or seedling from early season diseases and insect pests improving crop emergence and its growth.

Lower seedling mortality.

Improved plant population and thus higher productivity.

Reduces the cost and the potential environmental impact.

Also reduces the probability of chemical residues in harvested grain.

Relatively easy and cheap to apply compared to broadcast sprays.

Gaseous poisons use to kill insects are called as fumigants. Fumigants are pesticides that form poisonous gases when applied. Some active ingredients are liquids when packaged under high pressure but change to gases when they are released. Other active ingredients are volatile liquids when enclosed in an ordinary container and so are not formulated under pressure. Still others are solids that release gases when applied under conditions of high humidity or in the presence of water vapor.

Failure in timely diagnosis of diseases and other pests has often been responsible for devastating losses. Reducing crop losses by keeping pests at bay is crucial to food security. Plant clinic is an innovative paradigm which plays a vital role in assuring food security and ushering prosperity by providing timely diagnosis and rendering necessary advice to the growers, gardeners and other stakeholders for managing pest problem in India. Plant clinics are all about plant health. Though the major role of plant clinic lies in diagnostics and advisory, the activities of plant clinic extend beyond plant clinic, with emphasis on extension, working more closely with farmers and organizations involved in promoting food production. The role of plant clinics beyond diagnostics and advisory. These are:

Introduction

Underutilized fruits provide nutrition and sustenance of life to the native communities and prevent widespread malnutrition, combat micronutrient deficiencies and other dietary deficiencies, as these are rich in vitamins, minerals, protein, carbohydrates and fats. Vitamins like A, E and minerals like calcium, magnesium and iron are abundantly available in these fruits, which help in building resistance against diseases. Many underutilized fruits contain more vitamin C and pro-vitamin A than the widely available commercial species. Consumption of these fruits by the rural people directly from the trees further maximizes vitamin intake.

A healthy diet depends on a diversity of foods rich in vitamins and minerals. Whether wild, semi-domesticated or fully cultivated, the underutilized and neglected species are important for the well being of local communities. These fruit trees provide the essential supplements that ensure a balanced nutritious diet. Diet diversity is an extremely important element of nutritional well-being, in part because more essential nutrients are consumed and also because it improves the taste of staple foods thus encouraging greater consumption. One of the most common causes for dietary deficiencies appears to be the decreasing diversity of traditional diets. Underutilized fruits are common snack foods that provide vitamins, minerals, proteins, etc. and play important role in diets.

Sugars and sweetners: Sugars are present in all the actively metabolising plant cells in the form of glucose and sucrose. The under-exploited fruits that yield sugar are black maple, sugar maple, sugar palm, wild date palm, honey palm or coquito palm (Jubaea chilensis), talipot palm, nipa palm, toddy palm, palmyra palm (Table 1).

Introduction

The hot arid regions are spread over about 31.7 million ha area mainly in the States of Rajasthan, Gujarat, Andhra Pradesh, Punjab and Haryana, which inhabit on an average 61 persons per square km making up a population of nearly 20 million people. The Indian arid zone is characterized by high temperature and low and variable precipitation which limit the scope for high horticultural productivity. However, these conditions greatly favour development of high quality production in number of fruits such as date palm, ber, pomegranate, citrus, aonla, bael, grapes, guava and in vegetables such as cucurbitaceous crops, spices and some medicinal plants. The optimized technologies and inputs could increase the existing low productivity. It is now realized that there is a limited scope for quantum jump in fruit and vegetable production in the traditional production areas. The amelioration of the extreme conditions is also considered vital for life support to the inhabitants of this area. The recent awareness regarding the potential of these ecologically fragile lands for production of quality horticultural produce has not only opened up scope for providing economic sustenance for the people of this region, but also for bringing new areas to increase production through horticulture.

Introduction

While Indian agriculture has evolved to provide food to our ever growing population, nutrition security still remains a distant dream. Fruits an important component of a healthy diet, are rich source of nutraceuticals. Such health components comprising of flavonoides, carotenoides, vitamins, anthocyanins and other polyphenolics provide health benefits of disease prevention through antioxidant activity and reduced disease risks. Of late there has been an explosion of consumer interest in the health enhancing role of physiologically-active specific food components commonly referred to as nutraceuticals and functional foods.

The term ‘nutraceutical’ was first coined by an American doctor Stephen DeFelice in the 1990s. Today, healthcare market is flooded with different new nutraceutical related terminologies like, cosmeceuticals, biopharmaceuticals, herbaceuticals, ayuraceuticals, dermaceuticals, nutri-cosmetics etc. A review of 200 epidemiological studies showed that cancer risk in people consuming diets high in fruits was only one-half that in those consuming few of these foods. Increased acceptance and use of nutraceuticals and functional foods in the western world has resulted in increased export of such commodities from these countries. World-wide market for nutraceuticals and medicinal plant products today has surpassed US $ 15 billion with the top markets being United States (US $ 3 billion), Europe (US$ 2.4 billion), Japan (US$ 2.7 billion) and Asia (US$ 2.7 billion). It is increasing at the rate of 10% per annum. USA holds a significant share (35%) in world nutraceutical market followed by Japan (25%). As per the US estimates, the market for natural food colorants is estimated at US $ 500 million out of which anthocyanin and lutein together account for US $ 200 millions. Other large, emerging international markets in south and southeast Asia and mid-east gulf countries include UAE, Qatar, Oman and Kuwait. At present nutraceuticals and food supplement based functional foods account for trade worth US$ 170 billions and India’s share in this market is less than one per cent.

India is emerging as a major stakeholder in the global horticulture scenario accounting for 10.00 % of the world production of fruits. This has been made possible due to concerted efforts of scientists and progressive farming community. In recent years, there is considerable awareness about the nutritional security and food safety. Underutilized fruit trees not only provide nutrition and income security to the people but can also ameliorate the harsh environment of the semi-arid and arid region. Jamun has been named as diabetes fighter for its hypoglycemic (lowering blood sugar) properties.The minor fruits like bael, karonda, khirni, mahua, tamarind, mulberry, pilu, chironji, phalsa and wood apple have tremendous scope for their proper utilization. These fruits are nutritionally rich in bioactive compounds and some of these are of great medicinal value, processing quality and other uses. They have a growing demand in local as well as export market and for processing besides diversification in agriculture in the wake of global changes in weather conditions.

Introduction

During the last few decades, interest in Ethnobotany has evolved substantially world wide, particularly in India, Africa, Mexico, South America, and South-East Asia. Ethnobiological information on what and how local people make use of plants and animals have been traditionally gathered and passed on from generation to generation. India represents one of the greatest emporia of ethnobotanical wealth. Like other parts of India, in hot arid region also, rural and tribal communities have precious information about utilization of indigenous plants. Besides identification of plants as food, fodder, medicine etc., there also exists similar experience on life support species for exigencies like drought and famines, which is less utilized so far. Several researchers made contribution on etnobotanical aspects of Thar Desert. During 19^th century, King (1869 and 1870) listed wild plants used as food and vegetables during famine by people of Marwar region of Thar Desert. Afterwards, ethnobotanical aspects of edible plants of this region was attempted by several workers

Introduction

Vegetables are essentially important functional foods capable of providing additional physiological benefits such as delaying onset of chronic diseases apart from meeting basic nutritional requirements. Vegetables constitute a significant source of carotenoids, phenolics, vitamin C, flavonoids and glucosinolates which boost the immune mechanism and have medicinal properties. The antioxidants in tomato, onions, carrots, garlic, brussel sprouts, peppers and green leafy vegetables and their potential health benefits are critically discussed.

Oxidative damage to biological molecules like DNA, protein and lipids induced by free radicals is considered to be linked with many degenerative diseases such as cardiovascular, cancer, ocular and neurological such as Alzheimer’s and Parkinson’s. Antioxidants from plant sources preserve an adequate function of immune cells against homeostatic disturbances and act as functional foods. Functional foods are foods which besides fulfilling the basic physiological function, have health promoting effect. There is a considerable epidemiological evidence indicating association between diets rich in vegetables and a decreased risk of cardiovascular disease and certain forms of cancer. Diets rich in fruits and vegetables contain high amounts of antioxidant compounds like vitamin C, vitamin E, carotenoids, flavonoids, tannins and other phenolic constituents which boost the immune mechanism.

Introduction

The semiarid and arid ecosystem is not only neglected in India but also the whole world in respect of socio-economic and scientific development. Middlefon and Thomas, 1997) reported the arid and semi arid covers 47% of land surface of the plant and home town to 1/3 of human population. Conventional plant breeding so far only increased the yield of crops grown under arid tropics at about half the rate achieved for crops grown in temperate regions (Turner, 2004, b). The major crop of other ecosystem are considered as under exploited crop of arid ecosystem. Tomato (Lycopersicon esculentum Mill.), is one such crop, which was domesticated in ancient Peru, has become the most popular and widely consumed vegetable in the world today, for its rich flavor and high nutritional value (Vitamins A and C)