TSPSC Group – I Mains,2024 Material useful for Paper - I : General Essay & Paper V : Science and Technology Biotechnology in Agriculture : ’Bio-pesticides’

 

TSPSC Group – I Mains,2024

Material useful for Paper - I : General Essay

&

Paper V : Science and Technology

 

Biotechnology in Agriculture : ’Bio-pesticides’

 

For  Examination guidance purpose only

For any clarification please refer to the prescribed text books

 

Time : 3 Hours                                                                                     Marks : 150 

 

Note : Answer all questions. Answer ONE question from each section.

Answer to each question should be limited to around 1000 words. All questions carry equal marks .

For GENERAL ESSAY PAPER :

Syllabus :

Section-I 1. Contemporary Social Issues and Social Problems. 2. Issues of Economic Growth and Justice.

Section-II 1. Dynamics of Indian Politics. 2. Historical and Cultural Heritage of India.

Section-III 1. Developments in Science and Technology. 2. Education and Human Resource Development

========================================================

 Paper V : Science and Technology :

Syllabus:

II. Modern Trends in application of knowledge of Science:

1. Crop Science in India; Characteristics of Plants - Crop plants, Forest species, Medicinal Aromatic plants, Useful and Harmful plants and utility for mankind.

2. Concept of Biotechnology and application of genetic engineering and Stem Cell Research. Biotechnology in Agriculture (bio-fertilizers,

bio - pesticides, bio- fuels, tissue culture, cloning) and Environment (Biotechnology in Environmental cleanup process)

3. Food bio-technology, Food safety and Food quality standards, Food Laws and Regulations. Recent trends in organic farming and farm mechanization. Safe Drinking Water – Defluoridation and other Techniques.

4. Microbial infections; Introduction to bacterial, viral, protozoal and fungal infections. Basic knowledge of infections caused by different groups of micro organisms- diarrhoea, dysentery, cholera, tuberculosis, malaria, viral infections like HIV, encephalitis, chikungunya, bird flu- preventive measures during out breaks.

 5. Vaccines: Introduction to immunity, Fundamental concepts in vaccination and traditional methods of vaccine production ( production of DPT and Rabies vaccine), Production of modern vaccines (production of Hepatitis Vaccine).

=========================================================

GENERAL ESSAY:

Biotechnology in Agriculture :  ‘Bio-pesticides’

 

Pests and pathogens cause a major loss of agricultural produce every year. Management of these menace using chemical pesticides and fungicides has come at the cost of long term agricultural sustainability. This non-judicious use of agrochemicals coupled with climate change worsened the situation leading to changes in pest and pathogen behaviour and development of resistance.

 

 

Insecticides are one of the key control measures to combat the insect pests for sustainable agricultural production in the world. Synthetic insecticides have been only strategy to control the resurgent and resistant insect population in of high value crops not only in India but also in the world.

 

 

Insecticides have also been important in improving the health of both humans and domestic animals; malaria, yellow fever, and typhus, among other infectious diseases, have been greatly reduced in many areas of the world through their use. Pesticides include insecticides that are mainly used in agriculture or in public health protection programs in order tor to protect plants from pests, weeds or diseases, and humans from vector-borne diseases, such as malaria, dengue fever, and schistosomiasis . Besides, insecticides are being extensively used in sports fields, building bottoms, lawn development, public urban green areas etc to prevent unwanted insect pests such as termites

 

Since the discovery of DDT, numerous pesticides (organochlorines, organophosphates, carbamates, pyrethroids, neonicotinoids, etc.) have been developed and used extensively worldwide with few guidelines or restrictions. Indeed, they help control agricultural pests (including diseases and weeds), plant disease vectors, human and livestock disease vectors and nuisance organisms, and organisms that harm other human activities and structures (gardens, recreational areas, etc.).

However, many pesticides have been found to be harmful to the environment and human health. Some of them can persist in soils and aquatic sediments, bio-concentrate in the tissues of invertebrates and vertebrates, move up trophic chains, and affect top predators. They have caused adverse effects on soil health, water quality, produce quality and developed problems like insect resistance, genetic variation in plants, toxic residues food and feed. Moreover dependence on chemical pesticides and their indiscriminate use caused several detrimental effects on ecosystem.

 

What are the disadvantages of chemical  pesticides and  insecticides ?

Ans:

Insect resistance to insecticides has been found to be mediated by various mechanisms in four different ways :

a) Metabolic resistance, due to an increased detoxification caused by the overexpression or conformational changes of the enzymes involved in the chemical insecticide metabolism, sequestration, and excretion. Cytochrome P450-monooxygenases, glutathione S-transferases, and carboxy/cholinesterases, microsomal mono-oxygenases, phosphotriester hydrolases, DDT-dehydrochlorinases are the main enzymes involved in this process.

b) Altered target site sensitivity/mutation, caused by a modification of the chemical insecticide site of action reducing or preventing insecticide binding at that site. Mutations in the voltage sensitive sodium channel (Vssc) gene are one of the most common causes of target-site resistance. Insensitive acetylcholinesterases, insensitive sodium channels, insensitive GABA (γ-amino butyric acid) receptor are few such examples.

c) Reduced penetration, due to modifications in the insect cuticle or digestive tract linings that limit the chemical insecticides absorption. However, the mechanism remains poorly understood, and its importance in Aedes species is yet to be confirmed.

d) Behavioural resistance, which includes modifications in insect behaviour that help to avoid the lethal effects of chemical insecticides. This is considered as a contributing factor that allows the insects to avoid the lethal dose of an insecticide

 

 

Introduction to Bio-pesticides :-

 

Microorganisms due to their extraordinary metabolic diversity are known to produce a battery of secondary metabolites including antimicrobial peptides, volatiles, toxins and enzymes. Many such microorganisms have been substantially utilized as biopesticides to control several phytopathogenic fungi, bacteria, nematodes and insect pests. Unlike their chemical counter parts, biopesticides aid to manage pests and pathogens without any adverse effects on soil health and environment. Microbial biopesticides developed with microorganisms like Trichoderma, Beauveria, Metarhizium, Bacillus, Pseudomonas are known for their role in management of pests and pathogens. With the increasing reports on emerging pests and pathogens, the biopesticides are expected to play a major role in sustainable management.

 

 

What are Bio-pesticides ?

 

Ans:

Biopesticides are formulations derived from naturally occurring compounds that manage pests through non-toxic and environmentally favorable means. Being living organisms (natural enemies) or products, biopesticides represent less of a risk to the environment and to human health.

 

 Biopesticides, classified into three broad classes, are increasingly used in pest control, and include semiochemicals, plant-incorporated protectants (PIPs), and compounds derived from plants and microorganisms.

 

 

Because of their advantages for the environment, target-specificity, efficacy, biodegradability, and applicability in integrated pest management (IPM) programs, biopesticides are gaining interest. Although biopesticides have seen significant advances in market penetration, they still make up a relatively small fraction of pest management solutions

 

What are the advantages of Bio-pesticides ?

 

Ans:

 

Biopesticides are biodegradable, action-specific, and can respond to chemical-pesticide-mediated pest resistance issues. Sustainable agriculture driven by biopesticides enhances social adequacy and economic productivity and provokes environmental protection. All three dimensions together constitute the tripartite concept of sustainable development.

 

Biopesticides have great authority in sustainable agricultural management due to their satisfying characteristics of controlling both the green chemistry principles (GC principles) and the tripartite concept of sustainable development .

 

 In recent years, biopesticides have grown in popularity and are thought to be more safe than conventional pesticides. Biopesticides are more focused on the target pests and, by their very nature, are less harmful than traditional pesticides. Biopesticides can also be used sparingly and are rapid to disintegrate without leaving any unfavorable residues, which could lessen the need for conventional pesticides in integrated pest management.

 

Biopesticides are environment friendly and safer than classical chemical pesticides. Hence, in the recent years, considerable attention has been paid towards exploitation of biopesticides in protection of food crops/commodities from pest infestations and the associated losses.

 

They are more inclined to use eco-benign natural or herbal products in anticipation of any undesired side effects.

 

Natural occurring phytochemicals have been an excellent option to replace toxic chemical pesticides. It has been speculated that botanical pesticides could reduce the pest resistance problem, thereby often subdue deleterious effects of hazardous chemicals.

India has great diversity of flora and fauna. Treasure of bioactive phytochemicals from the diverse plant kingdom need to be exploited to develop newer bioactive molecules.

 

Recent report published by WHO showed more than 21,000 plant species worldwide have tremendous potential for being used in medicinal and phytochemistry. It is estimated that more than 30% of the entire phyto-population possessed active constituents with complex biofunctional characteristics.

 

Bioactive compounds derived from plants have proven to be valuable sources of bioactive secondary metabolites which can seldom be obtained from other sources

 

 

Three kinds of biocontrol products are being used in India which include :

 

1) Microbial biopesticides,

2) Plant-derived botanical pesticides, and

3) Pheromones or other natural insect growth regulators.

 

Microbial biopesticides consist majorly of fungi, bacteria, viruses or entomopathogenic nematodes as bioactive principles. In India, fungal based biopesticides share in the market is maximum  while Bacillus thuringiensis based products rank first in usage in USA, Europe etc.

 

Among fungal biopesticides, Trichoderma (only two species) based products approximately around 355 are readily available in the Indian market for the field applications .

 

Pseudomonas fluorescens based products are in wide spread usage over Bacillus based products globally with reference to bacterial biopesticide .

 

In India, strains of B. thuringensis, Bacillus sphaericus and Bacillus subtilis are registered as biopesticides.

 

Other non-spore forming bacteria like, Serratia entomophila and Chromobacterium subtsugae though have efficacy on limited range of insects are not evaluated systematically.

 

In India, two nucleopolyhedron viruses (NPVs) of Helicoverpa armigera, and Spodoptera litura are in use under field conditions in a smaller extent. Though the natural occurrence of granulovirus (GVs) of sugarcane pests in southern and northern states of India was reported, their commercial production are not yet started.

 

 

 Indian Council of Agricultural Research (ICAR) through its constituent institutes is engaged in development and evaluation of microbial biopesticides since last few decades. Some of the biopescticide formulations developed at ICAR are being validated through the network of AICRP-Biological Control of Crop Pests and Diseases. The recent invasions of fall armyworm (FAW) infesting maize and devastating infection of banana by Fusarium cubense TR4 have been successfully managed with microbial agents.

 

 

Types of Bio-pesticides :-

 

(1) Microbial biopesticides :—Microorganisms (bacteria, fungi, viruses, protozoans, or nematodes) are the main component of microbial pesticides. Although each individual active ingredient in microbial pesticides is quite specialized for its intended pest(s), they can control a wide variety of pests. These biopesticide classes have been effective in reducing weeds, plant diseases, and insect pests.

 

Microbial biopesticides can be applied to crops in a variety of ways, including as live organisms, dead organisms, and spores. Microbial pesticides work to reduce disease by producing a toxin that is particular to the pest that is being controlled. The effect of microbial infections is brought about by the pathogen’s infiltration through the skin or stomach of the insect, which leads to pathogen proliferation and the host’s, i.e., insect’s, death. The microbial pathogens generate insecticidal toxins that are crucial in their pathogenesis. Although their structure and toxicity might vary greatly, the majority of toxins generated by microbial infections are known to be peptides ; for example,Verticillium loeconi, Metarhizium anisopliae,   Bacillus thuringiensis , etc. Baculoviruses have a good prospect for the management of pests belonging to the orders Lepidoptera (butterflies and moths), Hymenoptera (sawflies), and Coleopteran (beetles). Chemical insecticides can be replaced with microbial pesticides since they are more effective. The insect pathogenic bacterium B. thuringiensis is the most commonly used microbial biopesticide (Bt). When bacterial spores develop, a protein crystal known as the Bt-endotoxin is produced. When ingested by insects that are vulnerable, this substance can lead to the lysis of gut cells. The target insect species is determined by the Bt crystalline protein’s binding to the insect gut receptor. Depending on the species, they are more or less pathogenic to the target pest.

 

(2) Biochemical pesticides:—Biochemical pesticides are organic compounds that use non-toxic methods to control pests. These are employed to modify an insect’s physiology, behavior, and even control . Semiochemicals are also included in this group of biopesticides. They might come from insects, animals, or plants. These categories of biopesticides include compounds such as plant growth regulators that prevent breeding and population expansion, as well as compounds such as pheromones that either repel or attract pests. When signals intended to cause a behavioral response are instead delivered to another organism, control becomes apparent . The fast-acting insecticidal chemicals pyrethrins, which are generated by Chrysanthemum cinerariafolium  , are a common example of secondary metabolites that plants make to prevent herbivores from feeding on them. Neem oil, an insecticide derived from the seeds of the neem tree, is the most popular botanical substance. At least two insect-killing chemical substances, azadirachtin and salannin, are produced by the neem tree. Azadirachtin inhibits insect feeding and controls growth .

 

(3) Plant-incorporated protectants (PIPs):—PIPs are biopesticidal compounds that are made by plants from genetic material that has been incorporated into the plant. For instance, researchers may insert the gene for the Bt pesticide protein into the genetic material of the plant. The pest-killing substance is then produced by the plant rather than the Bt bacterium. EPA regulates the protein and its genetic makeup but not the plant itself . This is also referred to as the non-conventional pest control product . PIPs are biopesticides that are directly expressed in the tissue of genetically modified (GM) crops in order to defend them against pests such as viruses and insects. When eating on the transgenic crop tissue, insect pests ingest PIPs. Cry protein and double-stranded ribonucleic acid are examples of PIPs (dsRNA). There are various Cry protein types, each having a distinctive structure and toxicity that is exclusive to particular insect groups. Cry1 proteins poison Lepidoptera (such as the corn borer), whereas Cry3 proteins poison Coleoptera (such as the corn rootworm). The first-generation insecticidal PIPs were cry proteins. Recently, the next-generation dsRNA PIPs received approval. The first dsRNA PIP authorized by the FDA interferes with the synthesis of the Snf7 protein, a crucial vacuolar sorting protein, in order to kill the maize rootworm.

 

 

What are the challenges in manufacturing the Biopesticides?

 

Ans:

Biopesticides have proved to be a very positive alternative to chemical pesticides; however, there is a long way to go before they can completely replace the other synthetic market. There are several pieces of evidence for the success of pesticides against a wide range of crop plants. However, it is not devoid of limitations.

Availability of plant sources: the production of a biopesticide is dependent on the availability of host plants in large quantities and their cultivation. Until now, these plants are grown for food, medicine, etc. Moreover, engaging in commercial production will require huge land areas, which are mostly all reserved for crop cultivation, hence the incapability of meeting the correct applied dosage remains inappropriate.

1)Formulation-: This is challenging as more than one active compound with different chemical properties can be derived from one plant. The extraction procedure requires the use of organic solvents, which pollutes the environment through their disposal.

2)Shelf life:- Compared to their rate of biodegradability, they have a very short shelf life. This has an impact on the cost of development, production methods, and inconsistency in their field performance.

 

3)Specificity:- Microbes form a very small portion of the entire pest community. Hence, these microbial biopesticides are only effective in controlling a small portion of the pest population. They are also slow in action compared to chemical pesticides.

 

4)Efficacy:- The effectiveness of microbial pesticides is susceptible to adverse climatic conditions. The effect is reduced by heat, desiccation, UV light, etc. Hence, it is important to precisely design the system of delivery. Moreover, they show mild toxicity to the pathogens and are inferior to the efficacy of conventional pesticides.