eChapters

14.1 Principles of X-ray Diffraction

Any crystalline structure is characterized by a regular and systematic arrangement of atoms (or ions) in a three-dimensional array. Since crystals are composed of regularly spaced atoms or ions, each crystal contains planes of atoms or ions separated by a constant distance which is the characteristic of that crystalline species.

X-rays are essentially electrostatic and electromagnetic fields oscillating in planes perpendicular to each other and to the direction of propagation in periodic cycles. X-rays having wavelengths in the order of 10^-3 to 10¹ nm, are produced within a vacuum x-ray tube by bombardment of a metal anode with high-velocity electrons. High-velocity electrons transfer their energy to the electrons of metal anode causing their elevation to higher energy level (excited state). Excited electrons of metal atom soon come back to the vacant shell and each electron transfer from higher to lower energy state results release of a quantum of energy (x-ray photon) equivalent to the difference in energy between these two levels. The energy and the wavelength of emitted x-ray photons are finite and characteristic of the particular atoms of the metal anode used in x-ray tube. Usually, photons generated due to electron transfer from L-shell to K-shell are used for x-ray diffraction analysis.

Diffraction of x-ray involves scattering of x-rays by planes of atoms of the crystal separated by definite distance and reinforcement of scattered rays in definite direction away from the crystal. Reinforcement of scattered rays is quantitatively related to the distance of atomic planes in a crystal as defined by Bragg’s equation:

15.1 Law of Mass Action

Gulberg and Waage, the two Norwegian chemists in the year 1864 stated the law of mass action in this form: ‘The velocity of any chemical reaction at any instant at a given temperature is proportional to the active mass of each of the reactants at that instant present in the system, the active mass in a homogeneous system is defined as the number of gram molecule of the substance present per unit volume i.e., the molar volume’.

16.1 Balance and Weighing

16.1.1 Principle of Functioning of a Balance

It is one of the important tools used in the laboratory and one should have thorough knowledge aboutitsassembly, use and care,otherwise it may be the initialstep for introducing error in any physical or chemical analysis. Every balancehas its maximum load limit and sensitivity depending upon its construction.

Essentially balance may be regarded as a rigid beam, BC having a central fulcrum, O and two arms of equal length, d₁, d₂ (Fig.16.1). Theboth ends of beam have prism edges upon which the balance pans are suspendedby means of suitable suspension.

17.1 Determination of Soil pH

The soil pH value is the measure of hydrogen or hydroxyl ion activity in the soil solution and it indicates whether the soil is acidic, neutral or alkaline in reaction. The pH is the most important property of soil as it controls the availability of plant nutrients, microbial activity and physical condition of soil. Since crop growth is affected both under very low (strongly acidic) and very high (strongly alkaline) soil pH, reclamation of these soils are necessary. Soil pH in fact indicates the extent of active acidity (activity of hydrogen ion in soil solution) of soil. Depending upon the purpose of measurement and soil condition, soil pH is measured in several soil-water or soil-salt solution ratios. The saturated paste is used for identifying specific soil problems like degree of acidity or alkalinity. For making fertilizer recommendation, 1: 2 soil-water suspension is generally adopted. To mask the variability in salt content of the soil, the pH is measured in soil-CaCl₂ suspension (1:2 soil-0.1 M CaCl₂ solution). The soil pH value is independent of dilution over a wide range of soil-salt solution ratio, thus more reproducible than those obtained with soil-water suspension.

18.1 Determination of Electrical Conductivity of Soil Solution

The conductivity or more precisely the specific conductance of a soil at a given soil-water ratio is the reciprocal of the specific resistance offered by the solution at 25ºC between the electrodes of 1 sq cm cross section kept 1 cm apart. Thus, the electrical conductivity of any solution depends on the amount of soluble salt present in it. Knowledge on the extent of salinity is important for management of saline soil including the choice of the crop suitable for that soil. Soluble salt content in saturation extract is more reliable index of salinity level than in soil: water ratio of 1: 2 or 1: 2.5, because it simulates the extent of salinity experienced by crop in field moisture condition.

Salinity class of soil is based on the electrical conductivity (EC) of saturation extract at 25ºC. However, EC of water extract from 1:2 soil-water suspension can be transformed into the EC of saturation extract following the formula (except for soil containing gypsum).

Carbon may be present in soil in four different forms:

1. Carbonates: Mainly as CaCO₃ and MgCO₃, active CO₃ ^2- and HCO₃ ^- ions and gaseous CO₂.
2. Highly condensed elemental organic form: Charcoal, graphite.
3. Completely decomposed resistant organic residues: Humus.
4. Undecomposed and partially decomposed organic residues.

The latter three fractions constitute the total organic carbon of which last two are chemically active form.

20.1 Exchange Capacity

Soil colloidal particles carry both negative and positive charges on their surface which attract and hold equivalent amount of oppositely charged ions to their surface. The total number of negative charges present on a given mass of soil or capacity of a given mass of soil to exchange cations or total number of cation held by a given mass of soil is termed as cation exchange capacity (CEC). Similarly, the capacity of a soil to retain anions is known as anion exchange capacity (AEC). The ion exchange capacity of a soil depends upon the type and amount of colloidal particle (clay and organic matter) present in the soil. Ion exchange capacity (CEC/AEC) is expressed as milliequivalent ion (cation/ anion, respectively) per 100 g of soil (meq/100g). It is also expressed as centimoles of charge (positive/negative) per kg of soil [cmol (±) / kg]. Meq/ 100g = cmol (±) / kg of soil.

20.1.1 Determination of Cation Exchange Capacity of Soil Principle

Soil is first saturated with normal ammonium acetate (pH 7.0). Excess ammonium (NH₄⁺) ions and displaced cations are then removed by washing with alcohol. The amount of NH₄⁺ ions retained by the soil is measured by steam distillation of NH₄-saturated soil with MgO. During distillation evolved ammonia is absorbed in a boric acid solution as ammonium borate and the amount ammonium borate formed is determined by titration with standard sulphuric acid in presence of mixed indicator.

21.1 Determination of Total Nitrogen in Soil (Modified Kjeldahl Method)

Nitrogen mostly present in soil in organic form. Relatively small amount of nitrogen usually occurs in ammonium and nitrate form, the available form. The Kjeldahl method of total N determination includes both organic and ammonium forms and with modification nitrate form of N can also be included.

Principle

When soil is digested with concentrated sulphuric acid organic nitrogen is converted to ammonium sulphate. To speed up the reaction a digestion mixture composed of sodium (or potassium) sulphate (to raise the boiling point of H₂SO₄) and cupric sulphate (CuSO₄) - selenium powder (catalyst) is used.

Phosphorus is present in soil both in inorganic form and organic form. The inorganic P can be divided into different pools. The major active inorganic forms are: P bound to aluminium (Al-P), iron (Fe-P), calcium (Ca-P) and silicate minerals and relatively less active forms are occluded and reductant soluble forms of P. On the other hand, the principal organic P compounds present in soil are (i) inositol phosphate, (ii)phospholipids, (iii)nucleicacid and other unidentified esters and phosphoproteins.

22.1 Determination of Available Soil P

The availability of soil P to plant varies greatly depending upon the reaction, minerological composition and amount of the soil colloid. Very little P is present in the soil solution except in recently fertilized or sodic soils. The type of phosphate ions present in the soil solution depends on the soil pH. In soils of neutral to slightly alkaline pH, HPO₄^2-ion is the dominant form. In slightly or moderately acidic soils, both HPO^-and HPO^2-ions prevail. At strongly acidic soil HPO 244 24 ion tends to dominate, while above pH 9.0, the PO₄^3-ion becomes more important - than H₂PO₄ .

As the P is drawn from soil solution largely through diffusion by the plant, it is replenished from solid phase pool of available P. P fertilizer is added to recharge this pool.

23.1 Forms of Soil K

Ignoring potassium (K) in soilorganism, total K in soilmaybe classified as (i) water soluble K, (ii) readily exchangeable K (exchangeable K), (iii) slowly exchangeable K (non- exchangeable or fixedK) and (iv) mineral or lattice K. Thedifferentforms are in dynamic equilibrium with one another.

Sulphur (S) occurs in soil in both organic and inorganic forms. Inorganic S fraction may occurs as sulphate (SO₄^2-) and compounds of lower oxidation state such as sulphide (S^2-), polysulphide (S_n^2-), thiosulphate (S₂O₃^2-) and elemental sulphur (S⁰). In well drained soils inorganic S usually present as sulphate. Under anaerobic condition (reduced or waterlogged soil) inorganic S mainly occur as sulphide and under extreme condition as elemental S form. Estimation of S is carried out in two steps:

1. Extraction of different forms of S from soil by suitable extractant.
2. The filtrate is then analysed for S by the turbidimetric method.

The turbidimetric method is the most widely used one because of its simplicity and rapidity.

25.1 Determination of Available Micronutrient cations (Zn, Cu, Fe and Mn) in Soil

The available micronutrient cations (Zn, Cu, Fe and Mn) can be estimated in a single extraction with diethylene triamine pentaacetic acid (DTPA) as proposed by Lindsay and Norvell (1978). DTPA has the excellent property to combine with free metal ions in the solution forming soluble complexes. The stability constants of metal-DTPA complexes make DTPA as a most suitable extractant for simultaneous complex formation with Zn, Cu, Fe and Mn. In calcareous soil DTPAextractant may result overestimation due to excess dissolution of CaCO₃, causingrelease of occluded micronutrient cations which are not plant available. To avoid this excessive dissolution of CaCO₃, DTPA is buffered at pH 7.3 using triethanol amine (TEA). At this pH major part (3/4^th) of TEA is present as HTEA⁺ (protonation) and exchanges for Ca and Mg ion from the soil exchange site. This increases concentration of Ca and Mg in the solution phase and suppresses dissolution of CaCO₃. The DTPA has the capacity to form complex with each of the micronutrient cations 10 times of its atomic weight and it ranges from 550 to 650 ppm depending on the micronutrient cation.

The amount of cation in the extract is determined on an atomic absorption spectrophotometer (AAS). The experimental condition such as shaking time, DTPA concentration, pH and temperature during shaking influence the amount of Zn, Cu, Fe and Mn extracted. Increase in shaking time and temperature markedly influence the extractability of these cations.

26.1 Plant Available Fraction of Nickel, Cadmium, Lead and Chromium

The DTPA method was originally developed to extract Mn, Cu, Fe and Zn from slightly acidic to alkaline soils (Lindsay and Norvell, 1978), but in some cases it can be used for other metals also, such as Nickel (Ni), Cadmium (Cd), Lead (Pb) and Chromium (Cr). Among them Ni is considered as an essential micronutrient. The DTPA is used to extract soil metals by forming chelates with free metals in solution, which lowers their ionic activities so that additional quantities of metal are released from the soil colloids until equilibrium is attained. Triehanolamine (TEA) is used to buffer the extracting solution at pH 7.3 in an attempt to optimize the extraction of various metals. Calcium chloride is included in the extracting solution to minimize dissolution of CaCO₃.

Different diagnostic tools are designed to avert nutrient deficiency or sufficiency and if properly used both loss of yield and quality of crop can be minimized. Among several diagnostic tools, nutrient analysis of standing crop seems to be an efficient method in arriving at the need-based fertilizer scheduling for various crops.

Nutrient uptake by plants indicates the actual accessibility of nutrients in soil to the plants. Also, concentration of certain heavy metals in plant indicates their solubility in soil which leads to poor crop quality.Although, different plant species and even different varieties of same species may differ in their nutrient requirements, the concentration of nutrient element in plant can act as guide to support the soil test result in assessing nutrient supplying capacity of a soil and as a tool for correcting any deficiency if carried out early enough to prevent yield loss. However, analysis of harvested or mature crop is like a post mortem as this information only can help in nutrient management planning in subsequent years.

Like soil testingplant analysis also suffers from some limitations. Amongthem, the most important are the risk of sampling error as well as the chances of incorrect interpretation of test report in recommending fertilizers. Selection of right plant part and right stage of crop growth are very crucial for successful plant analysis.

Environmental stress can disrupt cellular structures and impair key physiological functions. Drought, salinity, and low temperature stress impose an osmotic stress that can lead to turgor loss. Membranes may become disorganized, proteins may undergo loss of activity or be denatured, and often excess levels of reactive oxygen species are produced leading to oxidative damage. As a consequence, inhibition of photosynthesis, metabolic dysfunction, and damage of cellular structures contribute to growth perturbances, reduced fertility, and premature senescence. Responses to environmental stresses occur at all levels of organization. Cellular responses to stress include adjustments of the membrane system, modifications of the cell wall architecture, and changes in cell cycle and cell division. In addition, plants alter metabolism in various ways, including production of compatible solutes that are able to stabilize proteins and cellular structures and/or to maintain cell turgor by osmotic adjustment, and redox metabolism to remove excess levels of ROS and re-establish the cellular redox balance. At the molecular level, gene expression is modified upon stress and epigenetic regulation plays an important role in the regulation of gene expression in response to environmental stress.

Climate change drastically influence water availability, salinity and several adverse soil conditions which will have direct bearing on original yields. Abiotic stress factors influence growth and secondary metabolite production in higher plants. The influences are well marked. In fact, productivities depend on the changed ecosystem also. Secondary metabolites play a major role in the adaptation of plants to the changing environment and in overcoming stress constraints. This flows from the large complexity of chemical types and interactions underlying various functions: structure stabilizing, determined by polymerisation and condensation of phenols and quinones, or by electrostatic interactions of polyamines with negatively charged loci in cell components, photoprotective, related to absorbance of visible light and UV radiation due to the presence of conjugated double bonds, antioxidant and antiradical, governed by the availability of –OH, –NH2, and –SH groupings, as well as aromatic nuclei and unsaturated aliphatic chains, signal transducing. Several plant-abiotic stress stimuli systems evidenced the multiplicity of biochemical mechanisms involved in the protective role of secondary metabolites:

Abiotic Stress in Plants
             
World population is growing at an alarming rate and may reach about 6 billion by the end of the year 2050. Though, the agricultural productivity is also being increased world over, yet it is not keeping pace to meet the demand of food availability. The main reasons for limiting the agricultural productivity are water shortage, depleting soil fertility and mainly various abiotic stresses and climatic change. Minimizing these loses is of primary concern for all nations to cope with the increasing food requirement. The abiotic stress is defined as the negative impact of non living factors on the living organism in a specific environment and abiotic stress is the most harm full factor concerning the growth and productivity of crops worldwide. Researches have shown that abiotic stressors are at their most harm full when they occur together in combination of abiotic stress factors (Mittler, 2006; Bianco and Defez, 2011). Numerous stresses caused by complex environmental conditions i.e. drought, too high and too low temperatures, freezing, salinity, UV light, heavy metals and recently through smog (air pollution) leading to substantial crop losses worldwide (Mahajan and Tuteja, 2005). The abiotic stresses might increase in the near future even because of global climatic change.

Plants that are affected by various abiotic stresses react differently as a result such as the reduction in organ size or a change in the antioxidant enzyme system, and while drought and heat are often studied separately, in nature they often occur together, meaning it is essential to carry out joint studies. Furthermore, and related to the above when we consider high temperature stress, one must always consider the use of water and nutrients by the plant and other physiological functions. The effects of heat stress can also be analyzed by the technique that measures lipid peroxidation in polyunsaturated acids of the plasma membrane. The accumulation of metals in plants, affects the normal processes of plant metabolism. The study shows that there is a relationship between high metal contents in plants and their modified morphology: strong reduction of leaf thickness, modified parenchyma structure, and decreased mitochondria organization were ascertained, although toxic symptoms were apparently absent. Water-deficit stress has a significant effect on plants growth and development, with primary affects on plant structure, leaf morphology and cell ultrastructure. Physiological processes such as stomatal conductance, photosynthesis and respiration are consequently impaired with further implications on the metabolic functions such as carbohydrate and energy production as well as carbohydrate translocation and utilization.

The stresses, drought, salinity, chemicals, cold and hot temperatures, have interconnected effects on plants, resulting in the disruption of protein homeostasis. Maintenance of proteins in their functional native conformations and preventing aggregation of non-native proteins are important for cell survival under stress. The heat shock proteins buffer this environmental variation and are therefore important factors for the maintenance of homeostasis across environmental regimes. Heat shock proteins are known to be expressed in plants experiencing high-temperature stress. Heat shock proteins are important in relation to stress resistance and adaptation to the environment. Their molecular function might be membrane or protein stabilization, but, for now, for most heat shock proteins the molecular function remains to be elucidated. The general observation of the response and induction of heat shock proteins following heat stress suggests that they play a fundamental role in cellular homeostasis. It is possible that heat shock proteins may be involved with the phenomenon of acquired thermotolerance. Heat stress disturbs cellular homeostasis and can lead to severe retardation in growth and development, and even death. Temperature stress can have also a devastating effect on both the plant anabolism and catabolism, initially acting on protein complexes, being the quaternary structure the first folding that is lost during heat stress or heating. Understanding the role of HSPs in relation to stress resistance in a more applied perspective as a potential indicator of stress is important. New technological developments make it possible to investigate the role of genes coding for heat shock proteins in greater detail. A combination of genomics and proteonomics will further elucidate the effects of stress on expression patterns at the DNA, RNA and protein level.

The extreme temperatures those are consequences of present-day global climate changes are considered as major abiotic stresses for crop plants. Different studies clearly show that temperatures exceeding the limits of adaptation substantially influence the metabolism, viability, physiology, and yield of many plants. Plants exposed to extreme temperatures often show a common response in the form of oxidative stress. However, the extent of damage caused by extreme temperatures depends greatly on the duration of the adverse temperature, the genotypes of the exposed plants, and their stage of growth. There is ample need to develop temperature tolerance in crop plants by exploring suitable strategies. Numerous research findings support the notion that induction and regulation of antioxidant defenses are necessary for obtaining substantial tolerance against environmental stress. The development of genetically engineered plants, by the introduction and/or overexpression of selected genes, would to be one feasible strategy. However, plant adaptation to either high temperature or low temperature is a multigenic response which is very complex in nature. Thus the task of identifying the traits those correlate with stress tolerance is incredibly difficult for researchers. Plant response to continuous light depends on plant tolerance and can be modified by alteration in temperature, light intensity, CO2 level, and other environmental factors.

Most food legumes have a long history of domestication almost as long as cereals, and during this time they have been subjected to conscious and unconscious selections for better adaptation to environmental condition as well as better seed yield. In general, crops during their ontogeny faces a number of abiotic stress viz., excessive and/or low soil water stress, soil salinity stress, high as well as low temperature stress. It has been well documented that crop yields would be greater in many cropping regions if more water were available. 
Availability of water for agriculture is being challenged increasingly because of growing demand for water from other sectors such as industry, urban use, and for social and environmental purposes. Water stress may conceivably arise either from an insufficient or from an excessive water activity in the plant’s environment. Many physiological characteristics are correlated with the water potential of mesophyll tissue but the correlations are species specific. There is a general hierarchy of sensitivities among general physiological activities. Most sensitive are cell expansion, cell wall synthesis, protochlorophyll formation, and nitrate reduction. Generally turgor pressure is still accepted as the best indicator of water stress in plants. The specific mechanism by which turgor regulate physiological function probably relate to cell walls and membranes. Cell membrane structure, and spatial arrangement of enzyme, transport channels, cellulose synthesis rosettes, and receptor proteins may be dependent on turgor pressure.

We do not know when intercropping began nor why early civilizations fostered its use. Whether by design or accident, intercroppinq dominated early agriculture and is still practiced in many areas of the world. With the advent of “modern” agriculture, intercropping began disappearing from many areas. This shift was driven primarily by mechanization and specialization. Despite pressures to abandon intercropping, it has survived and flourished Inereasing interest in sustainability and environrnental concerns have drifted attention back to intercropping as a means of better utilization of resources while preserving the environment.
Through intercropping, farmers can achieve the full production of the main crop and also an additional yield (bonus) associated with an increased plant population of the second component. Hence, intercropping can increase incomes obtained by smallholder farmers in areas where labor is not shortage, through reduction of economic risk and market fluctuation resulting from growing a single crop which is more prone to natural hazards and helping the farmers in better utilization of land by having more than one crop produced per unit area. Though all intercrops produced higher productivity, the farmers could better use the appropriate population of component crops in intercropping systems in order to maximize yield of both crops as well as total productivity. It is, therefore, important to support intercropping systems with appropriate agronomic practices such as timely irrigation, pest protection and the likes to sustain the cropping system in the countries where labor is not problem for proper management in general even though sometimes sole cropping may became more productive.

Marginal land areas will need to be used to meet the increasing requirement of future generations, especially in developing countries. These marginal areas commonly impose abiotic stresses on crops due to factors such as salinity, drought, flooding, low nutrients and aluminium or heavy metal toxicity. As a consequence, the growth and yield of crops from such areas is typically low and their quality in also poor. Endogenous plant growth regulators play an important role in regulating plant responses to abiotic stress by sensitizing growth and developmental processes. While the physiological and molecular mechanisms linked to the role of ABA and cytokinins in stress tolerance are well explained, there is growing interest to elucidate the associations of auxins, ethylene, gibberellins, brassinosteroids, and polyamines in stress tolerance mechanism and also on possible cross talk mechanism among different growth regulators during stress tolerance acquisition. Identification and characterization of the gene regulating synthesis of different endogenous growth regulators and recent progresses on hormonal signaling, mutant research, and physiological actions have provided scope for manipulating their biosynthetic pathways for developing transgenic crop plants with enhanced abiotic stress tolerance. Researches have also provided some leads in exploiting the potential of growth regulators in enhancing the resistance to abiotic stresses of crops. Plant growth-regulators (PGRs), are biochemical and chemical compounds stimulates plant growth and productivity when applied, even in small quantities at appropriate plant growth stages. These are being extensively used in agriculture to enhance the productivity in agricultural crops. Their central role in plant growth and development is through nutrient allocation and source-sink transitions while most of the plant bioregulators (PBRs) stimulate redox signaling under abiotic stress conditions.

Plant–water relations concern how plants control the hydration of their cells, including the collection of water from the soil, its transport within the plant and its loss by evaporation from the leaves. Flow of water through plant and soil over macroscopic distances is driven by gradients in hydrostatic pressure. Over microscopic distances it is driven by gradients in water potential. Evaporation of water from leaves is primarily controlled by stomata, and if not made good by the flow of water from soil through the plant to the leaves, results in the plants wilting. Plant water deficit is initiated as the crop demand for water exceeds the supply. The capacity of plants to meet the demand and thus avoid water deficit depends on their “hydraulic machinery.” This machinery involves firstly the reduction of net radiation by canopy albedo, thus reflecting part of the energy load on the plant. Secondly, it determines the ability to transport sufficient amount of water from the soil to the atmosphere via the stomata in order to provide for transpiration, transpirational cooling and carbon assimilation. Water is transported by way the soil-plant-atmosphere continuum and it is largely controlled by the resistances in the continuum as determined by root, stem, leaf, stomata and cuticular hydraulic resistances. The gross effects of deficient and of excessive soil moisture on plant growth are well known, but controversy has existed for many years around the question whether the so-called “‘available moisture” is equally available for plant growth or available only with such increasing difficulty that plant growth functions are retarded before the wilting point is reached. Various measurable aspects of plant growth do not respond in the same manner to increasing moisture stress. Crops will respond to irrigations, although measured soil moisture stress is quite low. Problems of relating plant growth to soil moisture stress conditions varying with both time and soil depth are considered. Soil factors affecting density or depth are reviewed and several ways weather factors influence soil, -moisture-plant-growth relations summarized.

Partitioning of assimilated carbon among sink organs is a critical factor that controls the rate and pattern of plant growth. Environmental stress often restricts resource availability while successful acclimation sets in motion processes that restore the supply. A key mechanism contributing to regulation of carbon partitioning is an expression of genes that control activity of the enzymes which initiate sucrose metabolism at specific sites and stages of ontogeny. Drought stress not only limits the size of the source and sink tissues but the phloem loading, assimilate translocation and dry matter portioning are also impaired. However, the extent of effects varies with the plant species, stage, duration and severity of drought. Crop production faces many challenges, due to changing environmental conditions and evolving needs for new plant-derived materials. 
The extreme temperatures those are consequences of present-day global climate changes are considered as major abiotic stresses for crop plants. Temperatures exceeding the limits of adaptation substantially influence the metabolism, viability, physiology, and yield of many plants. Plants exposed to extreme temperatures often show a common response in the form of oxidative stress. However, the extent of damage caused by extreme temperatures depends greatly on the duration of the adverse temperature, the genotypes of the exposed plants, and their stage of growth. Numerous research findings support the notion that induction and regulation of antioxidant defenses are necessary for obtaining substantial tolerance against environmental stress. Plant adaptation to either high temperature or low temperature is a multigenic response which is very complex in nature. Plant response to continuous light depends on plant tolerance and can be modified by alteration in temperature, light intensity, CO2 level, and other environmental factors.

Though the pesticide application represents viable solution to pest control, however indiscriminate use poses threat to target as well as non-target crops. The side effects of pesticides therefore have to be considered based on their use and on the agricultural system to which particular pesticide is used. Studies should be implied on effects and persistence of pesticides in crops and is consequent effects on soil microbial flora and associated nitrogen metabolism. Safe alternate methods like development of relatively cheaper biopesticide should be encouraged. More efficient methods have to be developed and validated for dissipation of pesticide residues in food grains. Human health and environment has gained great importance in the modern world. The widespread use of insecticides has resulted in problems caused by its interaction with the natural biological systems. Study showed that higher amounts of acetamiprid have some negative effects on corn plant physiology. Thus, the use of pesticide should be controlled following the standards of developed countries to protect health and the environment.

Plants are often exposed to various abiotic and biotic stresses and have developed specific mechanisms to adapt, survive and reproduce under these stresses (Pieterse et al., 2009). Abiotic stresses include drought, water logging, high temperature, cold(low temperature), salinity, chemical pollution (xenobiotics), uv radiation, heavy metal and oxidative and plants are also challenged by biotic stresses through microbial pathogens such as myco-plasma, nematodes, fungi bacteria (Tippmann et al., 2006). The biology of plant cell is more complicated with any foreign stimulus from the environment; multiple pathways of cellular signaling and their interactions are activated. These interactions mainly evolved as mechanism to enable the plant systems to respond to stress with minimum and appropriate physio- biochemical processes. Abiotic and biotic stress induces signals and theses signals are recognized by receptors, followed by generation of secondary messengers e.g. activation of ion channels, production of reactive oxygen species (ROS) Xiong et al., 2002, accumulation of hormones (Bari and Jones, 2009; Peleg and Blumwald, 2011) such as salicylic acid (SA), ethylene (ET), jasmonic acid (JA) and abscisic acid (ABA). Secondary messengers are responsible for modulating intracellular level of calcium, often initiating protein phosphorylation cascade, which may leads to the activation of various proteins directly involved in cellular protection (Tippmann et al., 2006) Fig.1.

Globally, agriculture productivity is challenged by abiotic and biotic stresses, but abiotic stresses in particular (Gong et al., 2013) affect spreading of plant species across different environmental zones (Chaves et al., 2003). The changing climate is expected to worsen abiotic factors globally and adaptation strategies need to be established for target crops to specific environments (Beebe et al., 2011). Connect between different stress factors will likely surge harm to crop yields (Beebe, 2012). Soil salinity is a major environmental constraint to agricultural productivity (Greenway and Munns, 1980; Rhoades and Loveday, 1990). High concentrations of different types of salts, including chlorides, carbonates, and sulfates of magnesium, calcium, potassium, and sodium, characterize different saline soil areas around the world. Moreover, for each type of naturally occurring salinity, constantly changing environmental conditions, such as temperature and precipitation, as well as agricultural practices cause rapid modifications in levels of salinity and salt distribution patterns. Sodium and chloride are the predominant ions in the vast majority of saline areas.

During evolution, various species of plants, known as halophytes, readapted to life in high-salinity environments, but a large majority of plant species grown in non-saline areas are salt-sensitive (referred to as glycophytes). These glycophytic plants, including the majority of crop species, differ greatly in their tolerance to salt stress (Greenway and Munns, 1980; Flowers and Colmer, 2008).

Growth and development of plants are dependent upon the temperature surrounding the plant and each species has a specific temperature range represented by a minimum, maximum, and optimum. These values were summarized by Hatfield et al. (2008, 2011) for a number of different species typical of grain and fruit production. The expected changes in temperature over the next 30 to 50 years are predicted to be in the range of 2 to 3°C Intergovernmental Panel Climate Change (IPCC) (2007). Heat waves or extreme temperature events are projected to become more intense, more frequent, and last longer than what is being currently been observed in recent years (Meehl et al., 2007). Extreme temperature events may have short-term durations of a few days with temperature increases of over 5°C above the normal temperatures. A recent review by Barlow et al. (2015) on the effect of temperature extremes, frost and heat, in wheat (Triticum aestivum L.) revealed that frost caused sterility and abortion of formed grains while excessive heat caused reduction in grain number and reduced duration of the grain- filling period. Analysis by Meehl et al. (2007) revealed that daily minimum temperatures will increase more rapidly than daily maximum temperatures leading to the increase in the daily mean temperatures and a greater likelihood of extreme events and these changes could have detrimental effects on grain yield. If these changes in temperature are expected to occur over the next 30 years then understanding the potential impacts on plant growth and development will help develop adaptation strategies to offset these impacts.

Food productivity is decreasing due to detrimental effects of various biotic and abiotic stresses; therefore minimizing these losses is a major area of concern to ensure food security under changing climate. Environmental abiotic stresses, such as drought, extreme temperature, cold, heavy metals, or high salinity, severely impair plant growth and productivity worldwide. Drought, being the most important environmental stress, severely impairs plant growth and development, limits plant production and the performance of crop plants, more than any other environmental factor (Shao et al., 2009). Plant experiences drought stress either when the water supply to roots becomes difficult or when the transpiration rate becomes very high. Available water resources for successful crop production have been decreasing in recent years. Furthermore, in view of various climatic change models scientists suggested that in many regions of world, crop losses due to increasing water shortage will further aggravate its impacts. Drought impacts include growth, yield, membrane integrity, pigment content, osmotic adjustment water relations, and photosynthetic activity (Praba et al., 2009). Drought stress is affected by climatic, edaphic and agronomic factors. The susceptibility of plants to drought stress varies in dependence of stress degree, different accompanying stress factors, plant species, and their developmental stages. Acclimation of plants to water deficit is the result of different events, which lead to adaptive changes in plant growth and physio-biochemical processes, such as changes in plant structure, growth rate, tissue osmotic potential and antioxidant defenses (Duan et al., 2007 and Shakeel et al., 2011).

Crop yields are affected by a combination of abiotic stresses, biotic stresses, and nutritional factors but abiotic stresses (drought, heat, cold or salinity) are the major factors that prevent crops from realizing their full yield potential (Edmeades, 2009). In traditional approach, breeders grow and cross varieties and then evaluate how the progenies vary in their ability to deal with stresses. The best-adapted plants are then selected for growing in fields exposed to stresses. Biotechnologists have taken advantage of recent advances in biotechnology and functional genomics to genetically engineer crops which can give better yield in adverse conditions than the unmodified ones (Manavalan et al., 2009; Umezawa et al., 2006). Drought, extreme temperatures (high or low), high salinity and cold are the major abiotic stresses that affect plant growth and result in significant yield losses. Although plants have evolved a wide spectrum of programs for adaptation to changing environment, the current understanding of the mechanisms associated with the ability of crops to maintain yield under abiotic stress are poorly understood (Witcombe et al., 2008; Munns et al., 2008; Bartels et al., 2005). New advances in ‘omic’ technologies are providing opportunities for identification of transcriptional, translational and post-translational mechanisms and signaling pathways that regulate the plant response. This chapter describers several examples of how modern crop technologies may be applied to broaden crop tolerance of various abiotic stresses and to increase total biomass.

Environmental constraints that include abiotic stress factors such as salt, drought, cold, extreme temperatures and heavy metalsalready a major limitingfactor for crop productivity and will soon become even more severe due to climate change conditions.Together, these stresses constitute the primary causes of crop losses worldwide, reducing average yields of most major crop plants by more than 50% (Boyer, 1982; Bray et al., 2000; Wang et al., 2003). Current climate change scenarios predict an increase in mean surface temperatures and drought that will drastically affect global agriculture in the near future (Le Treut et al., 2007).
 
Abiotic stresses trigger many biochemical, molecular and physiological changes and responses that influence various cellular and wholeplant processes (Wang et al., 2001, 2003). For example, drought, salinityand low temperature stress lead to reduced availability of water (alsoknown as dehydration/osmotic stress) characterized by a decreasedturgor pressure and water loss (Dhariwal et al., 1998; Boudsocq and Lauriere, 2005). Osmotic stress promotes the synthesis of the phytohormoneabscisic acid (ABA)which then triggers a major change in gene expressionand adaptive physiological responses (Seki et al., 2002; Yamaguchi and Shinozaki, 2006; Shinozaki andYamaguchi-Shinozaki, 2007).

Agricultural research has been primarily focused to assure food self-sufficiency and security, and little concern on nutritional value “nutritional security” or health promoting qualities of food being produced. Food security has three dimensions, namely: (1) endemic hunger caused by poverty-induced under-nutrition and malnutrition; (2) hidden hunger caused by the deficiency of micronutrients like iron, iodine, zinc and vitamin A in the diet; and (3) transient hunger caused by natural calamities or civilian conflicts. Micronutrient malnutrition is recognized as a massive and rapidly growing public health issue especially among poor people living on an unbalanced diet.
 
Although great progress has been made in reducing the prevalence of hunger, over 805 million people are undernourished in 2012-14, still unable to meet their daily calorie needs for living healthy lives. This number has fallen by 100 million over the last decade (Table: 1 & Table: 2; Source: FAO, 2014). Undernourishment refers to food intake that is insufficient to meet dietary energy requirements for an active and healthy life. About one in nine people go to bed daily on an empty stomach. In cases where food is available, often the quality of the food does not meet micronutrient (vitamin and mineral) needs. More than two billion people continue to suffer from nutritional deficiencies such as vitamin A, iron, zinc and iodine. Despite progress, the number is still high, and marked differences across regions persist. 

Soils are the basis of food production. Ninety five percent of our food is directly or indirectly produced on our soil. A healthy soil maintain a diverse community of organisms that helps in controlling pests (insects, weeds, and fungus) but also form beneficial symbiotic association with plant roots, recycle essential plant nutrients and improve soil structure. A healthy soil can also be a strategic ally in mitigating and adapting to climate change, as soil sequesters CO₂ and prevent to escape into the atmosphere. Beside this, it contributes to mitigate climate change by maintaining or increasing its carbon content. This can be said that the proportion of organic carbon is available more in the soil than combining both atmosphere and ground vegetation. Most of the soil organic carbon (SOC) stored in the first metre of the soil in the form of organic matter. However, organic matter degrades due to deforestation; deplete soil biodiversity, loss of nutrients as consumed by crop plants, soil compaction due to excessive use of agricultural machineries, soil erosion, water logging conditions, and urbanization, which release greenhouse gases like CO₂, CH₄, and N₂O into the atmosphere causing global warming and climate change. One third of all CO₂ emissions come from changes in land use (deforestation, shifting cultivation, and intensification of agriculture) whereas two-thirds of CH₄ and majority of N₂O emitted through agricultural practices (Kotschi and Müller-Sämann, 2004).

Pulses belongs to the family Fabaceae (earlier known as leguminosae) comprises more than 600 genera and about 18,000 species of cultivated plants. It is the second largest family after Poaceae (earlier known as Gramineae), in terms of food and vegetable protein source and of fodder. The sub-family Papilionoideae consist of 480 genera and about 12,000 species, of which only a few species are cultivated for human nutrition. Endowed with excellent food and fodder qualities, these crops also restore soil fertility by scavenging atmospheric nitrogen, adding organic matter, enhancing phosphorous availability and improving physical, chemical and biological properties of soil (Graham and Vance, 2003; Dita et al., 2006).

The word ‘pulse’ is derived from latin word ‘puls’ meaning pottage i.e. seeds used to make porridge or thick soup. Pulses or grain legumes in general are indispensible source of supplementary proteins to daily vegetarian diets (Table 1) these are regarded as “poor man’s meat”. Pulse proteins are chiefly globulins and contain low concentrations of sulphur containing amino acids such as methionine and cysteine, but higher concentration of lysine than cereals, pulses provide a perfect mix of essential amino acids with high biological value and also contain higher calcium and iron than cereals.

Stress, is usually defined as an external factor that exerts disadvantageous influence on the plant. In most cases, stress is measured in relation to plant survival, crop yield, growth (biomass accumulation), or the primary assimilation processes (CO2 and mineral uptake), which are related to overall growth. Some environmental factors (such as air temperature) can become stressful in just a few minutes; other may take days to become stressful or even months (some mineral nutrients) to become stressful. Different types of abiotic stresses that affect fruit production are; water stress, heat stress, chilling and freezing stress, salinity stress, flooding stress. Although, it is convenient to examine each of these factors separately, many are interrelated. For example, water deficit is often associated with salinity in the root zone/ or with heat stress in the leaves. Plants often display cross resistance, or resistance to one stress induced by acclimatization to another. This behaviour implies that mechanism of resistance to various stresses share many common features.

Plants encounter adverse environmental stresses during their life cycle, which have negative impacts on growth and greatly affect crop productivity. As perennial crops, fruit trees are exposed to an array of stresses for a long time once they are planted. If the trees are severely injured by environmental stresses, it would be hard for them to recuperate, leading to retarded growth and reduced fruit production. Furthermore, the negative effects of the stresses are not limited to the fruit production in the current year but can also extend to the next year(s). Therefore, it is of critical importance to develop techniques for reducing stress injury and/or improving stress tolerance in fruit trees for sustainable cropping, which can be fulfilled by the cultivation method or genetic engineering (Holmberg and Bulow, 1998). 

India is the second largest producer of vegetables after China with 14 % contribution in total World vegetable production (1160 million tonnes). After the advent of green revolution, more emphasis is laid on the quality of the agricultural product along with the quantity to meet the ever-growing food and nutritional requirements. Both these demands can be met when the environment for the plant growth is suitably controlled. Olericulture a vital component of Indian Horticulture, which includes science and management of vegetables, has made a rapid stride during the last decade, recording appreciable growth in production (162.90 million tonnes against 81.89 million tonnes in 2000-01) and productivity (17.4 t/ha against 12.2 t/ha in 2000-01), availability (210 g/capita/day against recommendations of 300 g/capita/day) and export (36,94,860 tonnes worth Rs. 14,36,487 lakhs.) during 2013-14. Vegetables play a major role in Indian agriculture by providing food, nutritional and economic security and more importantly, producing higher returns per unit area and time (Srivastava et al. 2013). In addition, vegetables have higher productivity, shorter maturity cycle, high value and provide greater income leading to improved livelihoods. The total production of vegetables during 2013-14 was 162.90 million tonnes compared to 21.19 million tonnes in 1960-61, 81.89 million tonnes in 2000-01 and 146.55 million tonnes in 2010-11. Although, olericulture has exhibited leadership role but challenges are much greater. Looking to the requirement, which is estimated to be 225 million tonnes by 2020 and 350 million tonnes by 2030, which has to be produced from declining land and water resources and in the scenario of climate change, the task to meet the needs of growing population would be difficult but not impossible (Singh et al. 2014).

Plants are exposed to a wide range of environmental stresses and have to adapt physiologically to these as the local environment changes. Unfavorable soil properties, fertility imbalances, moisture extremes, temperature extremes, chemical toxicity, physical injuries, and other problems are some of the most discussed examples of abiotic disorders that can hamper plant growth which ultimately lead to death of the plants under extreme conditions. Furthermore, many of these abiotic stresses can predispose plants to diseases caused by infectious microbes. These stresses in plants also lead to a series of physiological, biochemical and molecular changes. Impact of biotic stresses on agricultural plants such as wheat, rice, maize, groundnut and many others have been top listed area of interest for researchers but until now, ornamental plants have not been a major object of such studies even though these plants constitute a major part of horticultural production and play an important role in everyday human life.
 
Ornamental plants are an integral part of the urban public places and private gardens. However, these plants are highly sensitive to abiotic stresses, which are known as the most harmful factor concerning the growth and development of these plants. Plant stress implies some adverse effect on the physiology of a plant induced upon a sudden transition from some optimal environmental condition.

Cereal crops are interchangeably called grain crops. In many publications and correspondence, they are simply called grains or cereals. As of 2012, the top 5 cereals in the world ranked on the basis of production tonnage are rice (paddy), wheat, maize (corn), barley and sorghum. These crops are also among the top 50 agricultural commodities in the world with maize ranking second next to sugarcane. Rice (paddy) ranks third, wheat - 4th, barley - 12^th, and sorghum - 30^th. Another cereal, millet, ranks no. 42 (FAO Stat 2014, updated Aug. 18, 2014). According to Chapman and Carter (1976), “a cereal is generally defined as a grass grown for its small, edible seed.” They also explained that all cereals are angiosperms, monocots, and members of the grass family Gramineae. Similarly, Lantican (2001) defines cereal or grain crops as agronomic crops belonging to the grass family Gramineae or Poaceae which are utilized as staples; the word “cereal” is derived from the most important grain deity, the Roman Goddess Ceres. Among the food grains cereals occupies for most status in human food requirements. Cereals are grown under different agro-climatic (Upland, Low land & Rainfed) conditions and it is most important staple food of about 65% of Indian population. Cereals crop is attacked by a large number of insect pests right from initial to till the harvest of the crops. Brief descriptions of the major crops, major insect pest and appropriate control measures are given below:

India is the largest producer and consumer of pulses in the world, accounting for 33 per cent area and 25 percent production. Pulses are mostly grown under rainfed conditions in marginal to sub-marginal lands. Once a net exporter it is presently one of the largest importer of pulses as our demand outstrips domestic production. While the traditional cropping pattern almost always included a pulse crop either as a mixed crop or in rotation, the commercialization of agriculture has encouraged the practice of sole-cropping. As a result, the annual import has increased from 0.50 million tonnes to 1.80 million tonnes during the last five years and contribution of pulses in the national food basket reduced from 17% to 7%. Pulses are generally grown on marginal and sub-marginal lands under rainfed conditions with low inputs and suffer heavily due to biotic and abiotic stresses, resulting into low productivity. Challenges for pulses in India are decline in area of pulses, low genetic yield potential, low realized yield, instability in production, climate change, biotic and abiotic stresses, poor seed replacement rate, post harvest losses, wide fluctuation in price, no regular MSP/procurement policy, poor availability of critical inputs in productivity zone and poor transfer of technology.

The oilseeds crop occupies an important position in agriculture economy in the world. Indian agriculture has made considerable progress, particularly in respect of food crops such as wheat and rice in irrigated areas; however, performance has not been so good in case of other crops particularly oilseeds, pulses, and coarse cereals. Therefore, after achieving self sufficiency in food grains the government is focusing attention on these agricultural commodities. On the oilseeds map of the world, India occupies a prominent position, both in regard to acreage and production. India is the 4th largest edible oil economy in the world and contributes about 10 percent of the world oilseeds production, 6-7% of the global production of vegetable oil, and nearly 7 percent of protein meal. This sector also has an important place in the Indian agricultural sector covering an area of about 26.5 million hectares, with total production of over 25.3 million tonnes in the triennium ending 2015-16 (GOI, 2016). This constitutes about 14.8 per cent of the gross cropped area in the country. A wide range of oilseed crops is produced in different agro-climatic regions of the country. Insects-pests are one of the limiting factors in the production of oilseed crops. Management of these pest problems by using possible control techniques could increase the quality and quantity of the products. These crops are damaged by a more number of insect pests, of which some are more serious. These pests can be effectively controlled by the integration of different techniques such as use of various safe insecticides/biopesticides, some modification in cultural practices and use of pest tolerant varieties. Integrated pest management approaches will help to increase the production and productivity of oilseed crops by reducing the pest damage without any adverse effect on the agro- system and erosion in the environment. 

Pest wise information of oilseed crop and management of major pests are described below.

Vegetable is an important constituent of Indian diet. India is the second largest producer of vegetables which contributes 16.7% to global vegetable area with a production of 156.33 million tons (15.4%) (Table 1). The level of productivity of vegetable17.4 tons/ha is quite low (Rai et al., 2014). Majority of Indians are vegetarian, with a per capita consumption 135 g per day as against the recommended 300 g per day. It is still very less than recommended diet level. In near future, there is a need of around 5-6 million tons of food to feed our 1.3 billion Indian population expected by the year 2020 (Paroda 1999). The major biotic stress in vegetable production is due to increased insect pest. In many cases, there is 100 per cent yield loss due to viral diseases vectored by insects. Vegetables are more prone to insect pests and diseases mainly due to their tenderness and softness as compared to other crops and virtual absence of resistance characters because of intensive hybrid cultivation. The insect pests inflict crop losses to the tune of 10-30 per cent in vegetable production (Table 2). To overcome these losses farmers used indiscriminate doses of toxic chemical on vegetable. It accounts for 13-14 per cent of total pesticides consumption, as against 2.6 per cent of cropped area (Sardana, 2005). For the benefit of the farmer and other, application of BIPM is must. Bio intensive pest management involves every part of management that keeps pest below economic injury level so that pest does not cause any economic loss to the farmers or growers.

Vegetables constitute a substantial part of human diet supplying vitamins and minerals, in which other food materials are deficient. India has emerged out as the second largest producer of vegetables in the world. More than 25% of fruits and vegetables are damaged by the attack of insect-pests (Pradhan, 1964).Vegetable crop is damaged by both sucking as well as chewing insect-pests. Sucking pests are aphids, whitefly, jassids and bugs attacking in initial stage whereas chewing pests like borers, infesting in flowering and fruiting stage. Sucking pests may transmit the viral diseases which cause severe loss in yield in tomato and okra crops. About 13-14 % of total pesticides used in the country are applied on vegetables. Average pesticide consumption in vegetables in India around 0.678 a.i. kg/ha. Maximum pesticide usage in chilli followed by brinjal, cole crops and okra. Global agro-chemical consumption dominated by fruits and vegetables, accounting 25 % of total pesticide market. Major insect-pests of different vegetable crops and their management are as follows:
 
Cole crops

Cabbage (Brassica oleracea var capitata) and Cauliflower (Brassica olercea var botrytis L) are grown in cold and moist climate. It is rich in minerals namely iron, magnesium, phosphorous and sodium. Cole crops were attacked by number of insect pests and cause heavy economic loss. The major insect pests are described below along with their management:

Okra Abelmoschus esculentus L.

Cotton Jassid Amrasca biguttula Ishida (Hemiptera: Cicadellidae)

Economic importance: Sucking pest cause damage during May to September. Adults are also found on plants such as potato, brinjal, tomato, etc.

Mark of identification and life cycle: Adults are about 3 mm long and greenish yellow during the summer, acquiring a reddish tinge in the winter. The winged adults jump or fly away at the slightest disturbance and are also attracted to light at night. Females lay about 15-38 yellowish eggs on the underside of the leaves, embedding them into the leaf veins. The eggs hatch in 4-5 days. Nymphs are wedge-shaped and are very active and complete five instars with 3-5 days in each instars. Adult live for 11days.

Nature of damage: Damage to the crop is caused by the adults as well as by the nymphs, both of which are very agile and move briskly, forward and sideways. They suck cell-sap from the underside of the leaves and pass through six stages of growth in 7-21 days. They feed constantly on the plant juice. The pest completes seven generations in a year. Damage symptoms: Injury to plants is due to the loss of sap and probably also due to the injection of toxins. The attacked leaves turn pale and then rust-red. With change in appearance, the leaves also turn downwards, dry up and fall to the ground.

Solanaceous Vegetables

Solanaceous vegetables are also infested heavily by several major insect pests.

Brinjal Solanum melongena L.
 
Fruit and shoot borer Leucinodes orbonalis Gunnee (Lepidoptera: Pyraustidae)

Economic importance: Most destructive pest of brinjal, found throughout the country. Besides brinjal, the pest is also known to infest potato, bitter gourd, pea pods, cucurbits and other solanaceous etc. The infestation on brinjal can be as high as 70 per cent. The pest is active throughout the year, except in severe cold weather in North India.
 
Mark of identification and life cycle: Moths wings are white with pinkish or black tings and are ringed with small hair along the apical and anal margins. The fore wings are ornamented with a number of black, pale and light brown spots. Female lays 80-120 creamy white eggs, singly or in batches of 2-4 on the underside of leaves, on green stems, flower buds or the calyces of fruits. Caterpillars are creamy when young, but light pink when full-grown in 9-28 days. Pupate in tough silken cocoons among the fallen leaves with period of 6-17days and adult survive for 2-5days of its life cycle. A single life-cycle takes 22 - 25 days extending up to 74 days during winter and there may be 8 - 12 generations in a year.

A systems approach to pest management based on an understanding of pest ecology is referred to as Biointensive Integrated Pest Management (BIPM). It is more dynamic and ecologically informed as compared to IPM that considers the farm as part of an agro ecosystem. Accurate diagnosis of the pest problem is the first step, which then relies on a range of preventive tactics and biological controls to keep pest populations within acceptable limits. It also considers ecological and economic factors into agricultural system design and decision - making and addresses public concern about environmental quality and food safety. As a last resort, the reduced – risk pesticides are used if other tactics have not been adequately effective.

The earlier concept of IPM has failed because of ease of applicability to easy availability of chemical pesticides. Hence, the present concept of BIPM, with more intensive use of biological and other biorational means has emerged. The flexibility and environmental compatibility of BIPM strategies make it useful in all types of cropping system. BIPM would likely decrease chemical use and costs entailing them. BIPM ultimately provides resistance / immunity to the entire system so that no foreign elements (insect pests or disease causing organisms) survive or gain upper hand. BIPM if followed for years shall enhance the natural control system, thus suppressing pest populations below those causing economic injury.

Fruit Flies and Economic Importance

Fruit flies belong to order Diptera (true flies) with one of the largest, most diversified and fascinating acalypterate family Tephritidae. These are commonly called as fruit flies due to their close association with fruits and vegetables and are also known as peacock flies because of their habit of strutting about and vibrating spotted and striped wings. Of the 4500 known species of fruit flies worldwide, nearly 200 are considered as pests but 70 species are regarded as agriculturally important throughout the world (Clarke et al., 2005, Schutz et al., 2012). David and Ramani (2011) reported 325 species in the Indian subcontinent of which 243 in 79 genera are from India alone. Important fruits flies damaging fruit crops in India include Oriental fruit fly or mango fruit fly, Bactrocera dorsalis (Hendel); peach fruit fly, B. zonata (Saunders); guava fruit fly, 
B. correcta (Bezzi); melon fly, B. cucurbitae (Coquillett) and ber fruit fly, Carpomyia vesuviana Costa, whereas important fruit flies in Punjab include B. dorsalis and B. zonata. Important host plants of B. dorsalis are mango, guava, peach, citrus, pear, ber and loquat but most preferred host of B. dorsalis is guava while that of B. zonata are guava, peach, mango, pear, ber, citrus and loquat but C. vesuviana infests only ber (Mann 1990, Sharma et al., 2005, Singh 2008b, Singh 2012, Singh et al., 2014a,b and Singh et al., 2015). Bactrocera dorsalis is considered to be the most damaging and aggressive fruit flies in the world (Leblance and Putao 2000). They are strong fliers and can fly upto two kilometers in search of food (Butani 1979).

Inorganic pest management systems using external inputs such as chemical fertilizers, pesticides, high yielding varieties have resulted in increased yields in certain areas, but resulted in ecological degradation hence a decrease in productivity. Under organic farming systems, the fundamental components and natural processes of ecosystems, such as soil organism activities, nutrient cycling, and species distribution and competition are used to work directly and indirectly as farm management tools. For example, crops are rotated, planting and harvesting dates are carefully planned, and habitat that supplies resources for beneficial organisms are provided. Soil fertility and crop nutrients are managed through tillage and cultivation practices, crop rotations, cover crops, and supplemented with manure, composts, crop waste material and allowed substances.
 
Bio intensive IPM incorporates ecological and economic factors into agricultural system design and decision making and addresses public concerns about environmental quality and food safety. The benefits of implementing bio intensive IPM can include reduced chemical input costs, reduced on-farm and off-farm environmental impacts, and more effective and sustainable pest management. An ecology-based IPM has the potential of decreasing inputs of fuel, machinery, and synthetic chemicals—all of which are energy intensive and increasingly costly in terms of financial and environmental impact. Such reductions will benefit the grower and society.

Nematodes are the most numerous metazoa on earth. They are either free living or parasites of plants and animals. Although currently only about 4100 species of plant parasitic nematodes have been described (i.e. 15 % of the total number of nematode species known), their impact on humans by inflicting heavy losses in agriculture is substantial. Most of the developing countries including India lie in tropical or sub tropical regions where climate is suitable for activity and multiplication of nematodes almost throughout the year. Sandy and warm soils such as found in India other developing countries in the arid zone are very favorable for nematode infection, especially in irrigated areas which are used for crop production continuously. The percentage of crop losses caused by plant pathogens, insect pests and weeds world wide has been estimated to 42% according for $500 billion worth of damage. The estimated overall annual yield loss of world’s major crops due to damage by plant parasitic nematodes has been reported to the extent of 12.3% (Sasser & Freckman, 1987). Estimated losses due to nematodes attack on different cultivated crops all over the world by FAO are around 400 million dollars. Annual crop losses in India is Rs. 242.1 billion. A large number of plant parasitic nematodes have been found associated with pulse crops in allover India but pathogenicity has not been proved for all. Plant parasitic nematodes are one of the most unwanted organisms in agricultural soils. They parasitize the roots of our carefully nurtured crops, reduce their ability to produce yields, make them weak and perhaps vulnerable to many pests and diseases. They reduce the crop yields that may equal those associated with more severe and easily identifiable plant diseases and we do not even realize their presence. Damage to crops by nematodes often goes unnoticed or attributed to other causes such as lack of fertility, deficient soil moisture. Sandy and warm soils such as found in India other developing countries in the arid zone are very favourable for nematode infection, especially in irrigated areas which are used for crop production continuously (Taylor, 1967).

A large number of insect pests are associated with stored grains which are directly related to geographical and climatic conditions. There are different estimates on post harvest losses in food. During storage both quantitative and qualitative losses occur due to insects, rodents, and microorganisms. Almost all the insect species may destroy 10.0 - 15.0 % of grain and contaminate with undesirable odour. These pests also helps in transportation of fungi. Some insect pests initiate damage at the ripening stage of crops and continue during storage. Major sources of infestations are old gunny bags, storage structure and old containers (Pruthi and Singh, 1950). The spread and distribution of stored product pests are facilitated by movement of grains from one area to another and by flight of insect pests as some of the adult insects are strong fliers. The cracks and crevices are probable sites for cross infestation. Nearly one thousand species of insects have been associated with stored products in different part of the world. Majority of insect pests belong to the orders Coleoptera and Lepidoptera (Khare, 1994).