eChapters

Shelf life for Pseudomonas fluorescens (TNAU Pf-1)

Aim: To find out the shelf life of P. fluorescens (TNAU Pf-1) using different carrier materials

Product: The talc based P. fluorescens (TNAU Pf-1) product is used for the study on shelf life.

Selective medium (King’B medium) for Pseudomonads

Crops are grown with the primary aim of maximizing the profit for the cultivators. To achieve this goal, high yielding cultivars and suitable agricultural practices are selected. But due consideration is not given for the levels of susceptibility of the cultivars and some of the agricultural practices may enhance the chances of disease incidence and consequent losses. Hence, it becomes obligatory to determine the effects of crop cultivar and agricultural practices on the extent of disease incidence and to assess losses caused by microbial pathogens in different crops in an agroecosystem. Crop losses reflect the effects of various factors such as use of disease resistant cultivars, application of chemicals, biocontrol agents and preventive measures to reduce inoculum levels, introduction of new diseases and restriction of disease spread. Assessment of crop losses is essential to choose the most effective short- and long-term strategies of disease management. Disease assessment enables the plant pathologists is to gather quantitative information for evaluating disease management strategies, for undertaking surveys of losses and breeding for disease-resistant cultivars.

Abstract

Information and Communication Technology (ICT) played and continue to play pivotal role in better decision making of farmers for plant health management under the climate change scenario. For judicious plant health management by farmers through the use of ICT tools (viz. interactive Kiosk, Mobile Apps, Whatsapp, Webportal), information need and information access network to be assessed. Based on farmers’ information need and network, information delivery tree should be designed in ICT tools. Under this backdrop this research work was carried out among the farmers of Bhagalpur district of Bihar. The sample size was 120. From the study it was noted that the major information needs of the farmers were seed availability, crop disease management, insect pest management, weed management and weather information and pesticide application. Farmers were enthusiastic to improve their knowledge on insect pests and disease identification and management. Specifically, farmers need information on insect pest management of wheat (aphid), maize (stem borer), vegetables (fruit borer), pulses (pod borer) and oilseeds (aphid) and also disease management of wheat (leaf blight and spot blotch disease), maize (Turcicum leaf blight), vegetables (wilt and leaf spot) and pulses (wilt disease). Farmers decision making was positively and significantly correlated with crop disease management(0.196*),insect pest management of crop(0.208*) and weed management(0.239**). Through the Path Analysis it was noted that farmers decision making on disease management was mediated by the variables - Bihar Agricultural University-Kisan Diary, Mobile Apps(Bihar Krishi Apps) and Kisan Salahkar. So, it can be concluded that these much needed information should be provided to the farmers though different ICT tools and extension personnel should be trained to operate these ICT tools for accelerated use of ICT tools by the farmers.

Introduction

According to an estimate by World Health Organization (WHO), about one million cases of pesticides poisoning and 20, 000 deaths occur every year due to pesticide residues in food chain including cereals, pulses, vegetables, fruits, oils, milk and milk products (including mother’s milk), fishes, poultry, meat and water. At global level, chemical pesticide worth US$ 30 billion is being used annually for the management of diseases and insect pests. In spite of this, epidemics of diseases, infestations of insect pests and colonization by weeds results in significant losses in agriculture production worldwide. As a result of crop improvement programs to incorporate resistance to pests, devastations epidemics and infestations are rare. Nevertheless, pests continue to exert a heavy toll in terms of yield losses. The last global estimate of yield losses due to pests, made crops like rice, wheat, maize, cotton, soybean, barley and coffee were equivalent to approximately US $ 250 billion annually during the period the period 1989-1990 (Table 1). Since these eight crops occupy only half of the global cropped area, yield losses due to all pests on all crops would be much high. The estimates indicate that 42 per cent of the total global attainable production of the eight major crops is lost due to pests, of which 16, 13 and 13 per cent losses are due to insects, diseases and weeds, respectively. Post harvest losses are estimated to cause an additional 10 per cent loss. Developing countries incur higher losses than industrial countries. (Table 2).

It is interesting to note that only 25 of about 1200 species of birds found in India have been reported to inflict damage to crops, vegetables and fruits. The exact ecological causes for population increase of individual species have yet to be studied. It would appear that, in general, the granivorous birds became abundant with the increase in area under grain crops and the subsequent storage of grain in godowns and bulk storage. The details of important bird pests are given below:

Bacteria

Definition

Bacteria belong to prokaryota which encompasses organisms with a primitive type of nucleus lacking a clearly defined membrane. The bacteria are smaller than fungi and measure about 0.5 to 1.0 x 2.0 to 5.0µ.

Introduction
Bacteria are single-celled prokaryotic organisms that can be both beneficial and harmful to plants. While many bacteria play essential roles in soil health and plant nutrition, certain pathogenic bacteria can cause severe diseases, leading to significant agricultural losses. Understanding the characteristics, life cycles, and management strategies for bacterial plant pathogens is crucial for effective disease control.
Characteristics and Morphology of Phytopathogenic Bacteria
General Characteristics
Phytopathogenic bacteria possess unique features that distinguish them from non-pathogenic strains:
• Cell Structure: Bacterial cells lack a true nucleus and membrane-bound organelles. Their genetic material is located in a single circular chromosome.
• Cell Wall Composition: Most phytopathogenic bacteria have a rigid cell wall composed of peptidoglycan, which provides structural support and protection. The composition of the cell wall varies, leading to classifications as Gram-positive or Gram-negative bacteria.

Definition
Bacteria belong to proakaryota which encompasses organisms with a primitive type of nucleus lacking a clearly defined membrane .The bacteria are smaller than fungi and measure about 0.5 to 1.0 x 2.0 to 5.0μ.
Structure of bacteria
1. A bacterial cell consists of a cell wall and a compound membrane enclosing protoplasm.
2. The protoplasm contains the nucleus, vacuoles, mesosomes, lipids, polysaccharides, mitochondric granules, and spores.
3. Bacterial cells may have flagella, pili, fimbrae, and capsules on the outside.
4. The bacterial cell contains a characteristics cell wall. The cell wall of bacteria is composed of a peptidoglycan. It is composed of acetyleglucosamine and cetyle-muramic acid .
5. The rigid peptidoglycan layer is located.
6. The latter layer is composed of lipoprotein . It is common in gram negative bacteria.
7. Many bacteria possess other intracellular membrane systems such as mesosomes and chondrioids.
8. The mesosome structure is formed by an invagination of the cytoplasmic membrane.
9. Mesosomes serve for compartmentalization and integration of biochemical systems.

Introduction

The soil around plant roots that forms the rhizosphere is a dynamic, complex zone. All plant parasitic nematodes are obligate parasities and must enter this zone to reach their host and cause damage (Kerry, 2000). Nematodes in soil are subject to infections by bacteria and fungi. This creates the possibility of using soil microorganisms to control plant-parasitic nematodes. Bacteria are numerically the most abundant organisms in soil, and some of them, for example members of the genera Pasteuria, Pseudomonas and Bacillus have shown great potential for the biological control of nematodes. Nematophagous bacteria are distributed broadly, possess diverse modes of action, and have broad host ranges. A variety of nematophagous bacterial groups have been isolated from soil, host-plant tissues, and nematodes and their eggs and cysts (Siddiqui and Mahmood, 1999; Kerry, 2000; Meyer, 2003).

They affect nematodes by a variety of modes: for example parasitizing; producing toxins, antibiotics, or enzymes; interfering with nematode–plant-host recognition; competing for nutrients; inducing systemic resistance of plants; and promoting plant health (Siddiqui and Mahmood, 1999). They form a network with complex interactions among bacteria, nematodes, plants and the environment to control populations of plant-parasitic nematodes in natural conditions (Kerry, 2000).

Introduction

Microorganisms are a great source of genetic diversity, still far from completely known and explored. The intimate association of plants with complex microbial communities is of great importance for the growth and productivity of plants in agriculture. There exists a definite difference in microbial community present in the bulk soil and the neighboring micro environments like phyllosphere, endosphere, rhizosphere and endorhizae. Microorganisms that colonize the plants’ rhizosphere are either pathogenic or beneficial according to their effects on plants and the way they interact with roots. The rhizosphere supports a plethora of microbial populations capable of exerting beneficial, neutral or detrimental effects on plant growth and development. Microorganisms such as bacteria, actinomycetes, protozoa, algae, fungi, and viruses coexist in the rhizosphere; bacteria are the most abundant among them.

1. Downy Mildew (Green Ear)
Sclerospora graminicola
Diagnostic Symptoms
• Characteristic symptoms of the disease are pale, chlorotic, broad streaks extending from base to tip of leaves.
• At the advancement of disease, the leaf streaks turn brown and the leaves become shredded longitudinally.
• In severe infection, the downy fungal growth can be seen on the upper as well as lower surface of the leaves.
• Infected plants fail to form ear but if formed, they are malformed to green leafy structures.
• Complete ear can be transformed into leafy structure.
• Pathogen transformed all floral parts such as glumes, palea, stamens and pistils into green linear leafy structures of variable lengths and no grains are produced.
• Partial infection of ear head is observed in which some grains are produced and rest of the ear head is converted in to a green ear(Fig-1).

By reducing losses from pests and diseases, the agrochemicals sector contributes significantly to raising agricultural output. In order to meet the challenges of feeding India’s growing population and bringing foreign exchange into the Indian exchequer through the export of high-quality agricultural products worldwide, the prudent use of crop protection chemicals promotes sustainable farm management and offers socioeconomic benefits. Nonetheless, most of the marginalised farmers who are forced to practise subsistence farming are able to produce only enough food to support their family.

Balsam (Impatiens balsamina) is an annual herbaceous flowering plant valued for its attractive flowers and use as a loose flower crop. It performs well under warm, humid conditions and is suitable for rainy-season cultivation. The chapter presents its origin, distribution, genetics, botanical characteristics, varieties and climatic and soil requirements. Detailed production practices include seed propagation, stem cuttings, micropropagation, land preparation, nutrient management, planting, irrigation, weed control, mulching, staking and pinching. Plant growth regulators, insect pests and diseases are also discussed. Particular attention is given to harvesting, postharvest handling and yield, making the chapter useful for commercial cultivation and practical floriculture education.

1. Sigatoka
Diagnostic Symptoms
• Early symptoms appear on the young leaves.
• Small spindle shaped spots on foliage with greyish centreand yellowish halo running parallel to veins.
• Spots are mostly seen along the edge of the leaf with defined margin and possess dark brown to black margin. Spots coalesce and whole leaf blade dries up.
• On the upper surface of the spots, fructificationsof the fungus appear as black specks unevenly and individual bananas appear undersized and their flesh develops a buff pinkish colour, and store poorly (Fig. 1).
Etiology
Scientific Classification
Kingdom : Fungi
Division : Eumycota
Sub- division : Deuteromycotina
 

Banana, Musa paradisiaca is one of the most important tropical fruit crops. India tops in the production of banana in the world and almost throughout the year banana fruit is available form one or another part of our country. Maharashtra, Tamil Nadu and Karnataka are the major states in cultivating and producing banana in India. The major insect pests associated with banana crop are described hereunder:

Banana weevil, Cosmopolites sordidus (Germar) (Curculionidae: Coleoptera)

It is most destructive and specific pest of banana and is distributed throughout the country. The eggs are elongate, oval (about 2 mm long), pearly white and present on upper surface and crevices of rhizome. The grubs are creamy white, stout, fleshy swollen in the middle and has red head capsule (Plate 10a). The full grown grub measures 15 mm in length. Pupae are white and found in the pupal chamber made in the periphery of rhizome. The newly emerged weevil is shiny reddish brown but soon becomes uniformly black (12.5mm in length). Longitudinal striations are found in the elytra and it does

Barleria, particularly Barleria cristata, is a perennial evergreen flowering shrub valued for attractive blooms, garlands, religious functions and ornamental landscaping. The crop has considerable commercial importance in southern India, while other species are used in ornamental and medicinal applications. This chapter covers the origin, distribution, genetics, botanical description and important species and varieties of Barleria. It explains suitable climate and soil conditions, propagation through seeds and stem cuttings, land preparation, nutrient management, planting and irrigation. Cultural practices such as weeding, mulching, pruning and pinching are described along with pest and disease management. Harvesting, postharvest handling and yield are also addressed.

Introduction

Entomopathogenic nematodes (EPNs) viz., Heterorhabditis, Neosteinernema and Steinernema have been recovered from many regions of the world and have been used commercially as biocontrol agents of insect pests. They are associated with mutualistic bacteria in the genus Xenorhabdus for Steinernematidae and Photorhabdus for Heterorhabditidae. The infective juvenile nematodes enter their host insect through natural openings (mouth, anus or spiracles), they release bacteria into the insect and cause rapid death of insect host (24-48 h). EPNs were used against many insect pests viz., rice leaf folder, Cnaphalocrocis medinalis (Srinivas and Prasad, 1991); tobacco cutworm, Spodoptera litura (Rajkumar et al., 2003); brinjal fruit borer, Leucinodes orbonalis (Hussaini et al., 2002) diamond back moth, Plutella xylostella (Singh and Shinde, 2002); Diaprepes abbreviates (Jenkins et al., 2007); Bemesia tabaci (QiuBaoli et al., 2008) and sugar beet beetle (Saleh et al. 2009).

A. Purchase

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

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

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

For the accurate identification and diagnosis of plant disease and plant problems a foundational knowledge of terms and definitions is vital for developing concepts, doing research, discussing and communicating issues and providing clarity to your work. The following terms and definitions are basic to the study of plant pathology. They are, however, just a brief introduction to the vocabulary of the science. If you have limited or no background in the subject and you are just getting started, the concepts and terminology of plant problems can seem somewhat daunting. However, your vocabulary and skill will develop through exposure to diagnostics, experience and correct use of the appropriate terms.

Plant pathology is the study of plant diseases and the abnormal conditions that constitute plant disorders. Etiology is the determination and study of the cause of disease. A pathogen can be living or non-living, but usually refers to a live agent. A pathogen is an organism which causes a disease. Pathological is a condition of being diseased. Pathogenic is having the characteristics of a pathogen and pathogenicity is the capability of a pathogen to cause a disease.

A plant disease is an abnormality in the structure and/or function of the host plant cells and/or tissue as a result of a continuous irritation caused by a pathogenic agent or an environmental factor. A disease is not static; it is a series of changes in the plant. All plants, to some extent, are subject to disease. Plant disease is the result of an infectious, or biotic agent or a noninfectious, abiotic factor. Plant injury is an abrupt alteration of form or function caused by a discontinuous irritant. Plant injury includes insect, animal, physical, chemical or environmental agents.

A causal agent is a general term used to describe an animate or inanimate factor which incites and governs disease and injury. A causal organism is a pathogen of biotic origin. When a pathogenic agent is virulent it can cause disease and if the agent is avirulent it is a variant of a pathogen that does not cause severe disease.