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It is said that “Success of any production system depends on the kind of seed which are sowing”. It is true for the seedlings also beacause healthy seedlings grown in a well managed nursery will decide the yield and consequently the profit.

Definition of Vegetable Nursery

A vegetable nursery is a place or an establishment for raising or handling of young vegetable seedlings until they are ready for more permanent planting.

Why vegetable nursery is needed

Some vegetable crops require special cares during their early growth period. There are some vegetables with very small sized seeds. Seedlings of many seed propagated vegetable crops like, tomato, brinjal, chillies, sweet pepper, cauliflower, cabbage, knolkhol, broccoli, Brussels sprout, kale, endive, chicory, celery, lettuce, parsley, onion, etc. are first raised in the nursery beds before transplanted in the main field. Many seed propagated vegetable crops viz., okra, peas, beans, radish, carrot, beet, turnip and all the cucurbits (e.g. bitter gourd, bottle gourd, pumpkin, cucumber, watermelon, muskmelon, snake gourd, sponge gourd, ridge gourd, etc.) are conventionally grown through direct seeding in the main field. However, many cucurbits, particularly in the early season are also grown in India using the seedlings raised in polythene packets.

The term ‘Phyto-hormone’ was coined by Thimann in 1948. Phyto-hormones are organic compounds, which are produced naturally in plants, synthesised in one part and usually translocated to the other part where in every small quantity affect the growth and other physiological function of the plants. Auxin was the first hormone to be discovered in plants. At one time, auxin was considered to be the only naturally occurring plant growth hormone however, four other classes of phyto-hormone viz., gibberellins, cytokinin, ethylene and abscisic acid was later discovered. Plant growth regulators include both five specified classes of phyto-hormones (auxin, gibberellins, cytokinin, ethylene and abscisic acid) and other synthetic organic compounds (for example, polyethylene glycol, dinoseb-2-sec butyl 4,6dinitrophenol, proteins and/or amino acids, carboxylic, phenolic acid, humic acids, etc.) having properties of bio-stimulants or bio-inhibitors. Plant growth regulators (PGRs) modify plant physiological processes either by stimulating or inhibiting specific enzymes or enzyme systems to help regulate plant metabolism and thereby enhance yield and product quality. They normally are active at very low concentrations in plants.

Importance of PGRs was first recognized in the 1930s. Since then, wide array of natural and synthetic compounds that alter function, shape and size of crop plants have been discovered. Of the many uses of PGRs, effects on yield are often indirect. A wide range of beneficial effects of PGRs on crop growth and yields are: 1. promotion of germination and/or emergence, 2. stimulation of root growth, 3. promotion, mobilization and translocation of nutrients within plants, 4. modification of flowering, 5. increase in stress tolerance and improvement of water relations in plants, 6. promotion of early maturity, 7. increase in disease resistance, 8. retardation of senescence and 9. improvement of crop yields and/or quality.

Development can be defined as the process and timing of differentiation of the component events causing qualitative changes in form and function of the plant and therefore, manifestation of economic plant parts. Sowing is the beginning of the process, after which plants emerge, grow and develop with or without transplanting and may be harvested in vegetative (e.g., cole, bulb, tuber, root, salad crops) or reproductive phase (solanaceous fruits, peas and beans, cucurbits, okra, etc.). Growth and development of plants is dependent on abiotic (physical) and biotic (biological) factors. Abiotic factors include the physical environmental conditions and biotic factors include animals, insects, and diseases. Each plant has certain environmental requirements. To attain the highest potential yields a crop must be grown in an environment that meets these requirements. A crop can be grown with minimal adjustments if it is well matched with its climate or growing condition. Unfavourable environmental conditions can produce a stress on plants resulting in lower yield. In such cases the environment can be artificially modified, as done in protected structures like poly house, shade net house, etc. to meet the crop requirements.

Different abiotic environmental factors viz., light, temperature, water and soil greatly influence plant growth and geographic distribution. These factors determine the suitability of a crop for a particular location, cropping pattern, management practices, and levels of inputs needed. A crop performs best and is least costly to produce if it is grown under the most favourable environmental conditions. To maximize the production of any crop, it is important to understand how these environmental factors affect plant growth and development.

Classification of Vegetable Crops

Vegetables are defined as herbaceous plant origin product with no calorific value and providing micronutrients, vitamins, antioxidants, fibre and alkaline reaction inside human body. Vegetable crops are not only botanically different but also their cultural and climatic adaptation also shows wide variability. It is, therefore, necessary to classify the vegetable crops for their easy recognition. Vegetable crops can conveniently be classified “Botanically” for the purpose of vegetable breeding and according to “Method of culture” from the point of crop husbandry.

Botanical Classification

Botanical classification involves grouping of plants into kingdom, division, sub-division, phylum, sub-phylum, class, sub-class, order, family, genera, species, sub-species and variety. The broadest group in which vegetables are discussed is family. The genus and species constitute the scientific name. Scientific names are accepted worldwide and there cannot be any confusion as per their nomenclature. All vegetable crops belong to the division Angiospermae. The division Angiospermae has two classes: Monocotyledoneae and Dicotyledoneae.

The crops used for vegetable purpose in the world belong to 1200 species under 78 families and of them, more than 860 species under 59 families belong to dicotyledoneae and about 340 species under 19 families belong to monocotyledoneae. In the tropical and subtropical parts of the world, about 90 species of vegetable crops are cultivated, but hardly 25 of them are commercially important in terms of market demand, development of variety/hybrid and seed production. In the present botanical classification, over 140 different kinds of vegetable crops under 7 monocotyledoneae and 20 dicotyledoneae families have been included.

Food, at the fundamental level, is viewed as a source of nutrition to meet daily requirements at a minimum in order to survive but with an ever greater focus on the desire to thrive. Nutritional security denotes the consumption and physiological use of adequate quantities of safe and nutritious food by every member of the family and encompasses the process of equitable distribution among members of household and communities. This would entail the need to ensure a varied food intake, comprising all the essential macro- and micronutrients (protein, carbohydrates, minerals and vitamins), plant pigments (lycopene, β- carotene, anthocianin, lutein, capsanthin, zeaxanthin, etc.) and other functional phytochemicals (secondary metabolites, like flavonoids, isothiocyanates, glucosinolates, etc.) through a diversified diet. The growing awareness in recent years of the health promoting food has directed increased attention to vegetables as vital components of daily diets.

Main Nutrient Components of Vegetables

Nutrient components of our food can be grouped into five main divisions, namely, (i) Carbohydrate, (ii) Protein, (iii) Fat, (iv) Vitamins and (v) Minerals. Balanced diet is the food containing all these nutrient components in balanced form to run the physiological process in good tune. So, only eating to one’s heart’s content may not be the criterion of a balanced diet. Our dietary constitution which is mostly cereal based is really alarming. Cereals, which supply chiefly carbohydrate, constitute only a part of the diet. Moreover, the present average carbohydrate supply through cereals is also not adequate. Chief deficiencies in our diet are calories, protein, vitamin A and riboflavin. According to the studies of Indian Council of Medical Research, New Delhi and National Institute of Nutrition, Hyderabad, meager intake of vegetables, the low cost protective foods, is largely responsible for malnutrition among the majority of our population. The dieticians advocate intake of 125g leafy vegetables, 75g other vegetables and 100g root and tuber vegetables (total 300g) everyday to make our diet balanced. In households below the poverty line, per capita vegetable consumption is very low, apprehended to be even lower than 40g per day.

Historical Account on Vegetable Cultivation in India

The vegetables have chequered history in India which dates back to prehistoric period before the arrival of Aryans in India (c. 1500-1000 BC). During the pre-historic times before the arrival of Aryans in India, the Proto-Australoids (Nisada) used brinjal, bottle gourd and watermelon as vegetables. Pea existed in India much before the Aryans came to the country and it was already present in Western Asia prior to its cultivation. The pea, most likely the field pea (Pisum sativum subsp. sativum var. arvense L.) was eaten during the Harappan civilization as evidenced from the archaeological excavations of Mohenjo-daro and Harappa (2500-1750 B.C.) in which carbonized pea seeds were discovered. Pea seeds were also found from Neolithic site (last stage of the Stone age) of Chirand in Bihar (situated 10 Km south-east of Chapra), Chacolithic site (period or Copper Age) of Maheshwar Nevdatoli (c. 1200 BC.) in Madhya Pradesh and part of Osmanabad district in Maharashtra. The presence of seeds of melon along with wheat was also recorded from the Harappan excavation. Plant remains of Chenopodium album, Portulaca oleracea and a few species of Solanaceae, Polygonaceae and Labiatae family during Mesolithic times (Middle Stone Age) were found at Mesolithic site of Damdama, Uttar Pradesh (c. 7000-6000 BC). Wood charcoals of plant remains of Lablab purpureus were found from the early phase of Indus-Saraswati (Sarasvati) or Indus Ghaggar-Hakra civilization (c. 3100-2800 BC). Kundru (Coccinia indica), cowpea and field pea were recorded from Hulas in Saharanpur district, Uttar Pradesh, late Indus valley civilization archeological site. Carbonized seeds of hyacinth bean (dolichos bean), peas, Phaseolus, Vigna and melon from Rojdi in Gujarat and Chenopodium and amaranth from Surkotada, Gujarat (c. 2300-1800 BC), both being the archaeological sites belonging to the Indus valley civilization also suggested the existence of vegetables in India in the pre-historic times. Among the vegetables eaten during the pre-historic period, like brinjal, bottle gourd, watermelon, peas and melon as mentioned earlier, only brinjal has its origin in India while the other were brought from other countries much before the arrival of the Aryans. It is difficult to understand how a few important Indian native vegetables, like cucumber, Luffa (smooth and ridge gourd), pointed gourd and Dolichos bean (Lablab purpureus) were not known at that time. Similarly okra which has a secondary centre of origin in India has not been mentioned in any ancient literature. However, Abelmoschus moschatus called “Lata kasturika” in Sanskrit as a source of perfume has been recorded in Carak Samhita. The use of bottle gourd, which is not a native vegetable, is known from pre-historic times. Its dried fruit-shell is used as a hand jug (utensils) by saints and monks and in musical string instruments, like ektara, tamboora, tanpura, sitar and veena. Even mythological paintings have always delineated Naradmuni with tamboora in his hand and the goddess Saraswati with Veena which suggest the antiquity of bottle gourd in India. However, its date of introduction and the place from where it came remain unrecorded. It is also not mentioned in any iconography of the Medieval period (9^th and 10^th Century AD).

Definitions

Selection, integration and implementation of disease control means on predicted economic, ecological, and sociological consequences.

A comprehensive approach to disease control that uses combined means to reduce the status of diseases to tolerable levels while maintaining a quality environment.

The optimization of disease control in an economically and ecologically sound manner, accomplished by the coordinated use of multiple tactics to assure stable crop production and to maintain disease loss below the economic injury level while minimizing risks to man and the environment.

A sustainable approach to manage diseases by combining biological, cultural, physical and chemical tools in a way that minimizes economic, health and environmental risks.

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

Fungicide Formulation

Fungicide formulation is the process by which the fungicide 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 disease control.The mixture of active ingredient and inert (inactive) ingredients is called a fungicide formulation.

Introduction and Concept

The word fungicide has originated from two Latin words: viz. fungus and caedo (to kill). So literally, a fungicide would be any physical or chemical agency which kills a fungus. However, the word is restricted to chemicals. Hence, the word fungicide should mean a chemical capable of killing fungi. However, there are a number of compounds which do not kill the fungus. They simply inhibit growth or spore germination temporarily. If the fungus is freed from such substances, it would revive. Such a chemical is called a fungistat. and the phenomenon as fungistasis. Some other chemicals, like certain phenantherene derivatives and bordeaux mixture may inhibit spore production without affecting vegetative growth. These are called antisporulants. There are other groups of chemicals which exhibit very poor or no antifungal activity in vitro condition but provide protection to the plants either by inhibiting the penetration of host surface by the fungi or by inducing the host defense system. The former type of chemicals are termed as antipenetrants and later as antipathic agents. Even though fungistats, antisporulants, antipenentrants, and antipathic agents do not kill fungi, they are included under the broad term fungicide because by common usage, the word fungicide has been defined as chemical substance which has ability to prevent damage caused by fungi to plants and their products. Fungicide which is effective only if applied prior to fungal infection is called protectants. On the other hand, fungicide which is capable of eradicating a fungus after it has caused infection, and thereby curing the plant, is called therapeutant.

Definition

Those characters that enable a plant to avoid tolerate or recover from attacks of pathogens under conditions that would cause greater injury to other plants of the same species.

Definition

Garret (1970) defined biological control as any condition under which or practice whereby survival or activity of a pathogen is reduced through the agency of any other living organism (except man) with the result that there is a reduction in the incidence of the disease caused by that pathogen.

Baker and Cook (1974) stated that the biological control is the reduction of inoculum density or disease producing activities of a pathogen or parasite in its active or dormant stage, by one or more organisms, accomplished naturally or through manipulation of the environment, host or antagonists, or by mass introduction of one or more antagonists.

Biocontrol can be simply defined as the application of living organism to control diseases.

1. Biosecurity

Biosecurity is strategic and integrated approach encompasses policy frameworks to analyze and manage risks for food safety, animal life and health and plant life and health including environment.

Introduction

Cultural management is defined as manipulation /or adjustment of crop production techniques for management of plant diseases. Cultural practices have been as old as possibly agriculture itself. In early stage of agriculture development, the growers through their experiences and observations had known that repeated cultivation of a particular crop species or variety on a piece of land often resulted in crop sickness. As a matter of fact, in the present day agriculture, cultural practices are being considered as essential backup methods for management of plant diseases. Adequate adjustment in crop production techniques can modify the environment in such a manner that it becomes unfavorable for the pathogen and pathogenesis. Based on this the disease control affected by cultural practices are preventive, these practices aim at reducing the activity and density of inoculum. It offer the opportunity to alter the environment, the condition of the host, behavior of the causal agent to achieve economic management of disease.

Introduction

Cultural management is defined as manipulation /or adjustment of crop production techniques for management of plant diseases. Cultural practices have been as old as possibly agriculture itself. In early stage of agriculture development, the growers through their experiences and observations had known that repeated cultivation of a particular crop species or variety on a piece of land often resulted in crop sickness. As a matter of fact, in the present day agriculture, cultural practices are being considered as essential backup methods for management of plant diseases. Adequate adjustment in crop production techniques can modify the environment in such a manner that it becomes unfavorable for the pathogen and pathogenesis. Based on this the disease control affected by cultural practices are preventive, these practices aim at reducing the activity and density of inoculum. It offer the opportunity to alter the environment, the condition of the host, behavior of the causal agent to achieve economic management of disease.

Defintion

Management of plant diseases using physical means is called physical management.

Also called physical therapy or thermotherapy.

It is mostly curative in nature.

The techniques used in disease management mainly based on two principles: Prevention or prophylaxis and cure. The first principle prevention includes disease management tactics applied before infection i.e., the plant is protected from disease. It includes: avoidance, exclusion, eradication, resistant & protection. Second principle curative action: functions with any measure applied after the plant is infected i.e., the plant is treated for the disease. It includes therapy.

Disease Forecasting

Definition

Forecasting involves all the activities in ascertaining and notifying the grower of community that conditions are sufficiently favourable for certain diseases, that application of control measures will result in economic gain or on the other hand, and just as important that the amount expected is unlikely to be enough to justify the expenditure of time, energy and money for control. The above statement made explicit distinction between positive forecast and negative forecast and both have value for growers as well as society in general.

Positive forecast: Employs need based chemical sprays, provides adequate protection to crop and reduces damage to environment.

Negative forecast: Avoids unnecessary chemical sprays, no risk to the crop health and no disruption of environment.

Epidemiology

Vanderplank has called epidemiology the science of disease in population. Epidemiology puts its emphasis on population phenomena. The important populations are those of the host, on the one hand, and of the pathogen, on the other. But further, epidemiology is concerned with host-pathogen interactions that lead to disease and crop losses. These interactions are often environmentally dependent. So epidemiology deals with effects of the biotic and abiotic environments. Finally , man has had important effects on hosts, pathogens and the environments, effect that today are increasing in magnitude and scale of importance. Epidemiology therefore also deals with the effects of man on disease and sometimes with the effects of plant disease on mankind. All of this can be symbolized by the disease tetrahedron.

Introduction

Resistance to disease in a host plants is a condition in which the plant conquer the pathogen’s attack and thus suffers small or no injury. Resistant hosts prevent or slow the development and reproduction of the majority of pathogen propagules that they come into contact with. Different plants defend themselves in different ways. Each kind of plant, probably, employs different defense mechanism against each of the pathogens that attack it. The defense barriers erected by plants are a co-ordinated system of molecular, cellular and tissue-based responses to pathogen attack.