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ISSN: 2582-6980
A I A S A A g r i c u l t u r e M a g a z i n e
Volume 02 | Issue 05
aiasanewdelhi aiasa5 AIASA www.aiasa.org.in
MAY 2021
A V o i c e f o r A g r i c u l t u r e
AGRI MIRROR : FUTURE INDIA
Senior Editor
Associate Editor
Advisor
Sahadeva SinghYadav M CAdiguru PSandeep Kumar
Kuleshwar SahuSudhir Kumar JhaSonica PriyadarshiniVinoth RVerma M K
Karthikeyan GAsish Kumar PadhyPraveen VermaRakesh KumarPriyank SharmaAshish GautamTapas PaulUtpalendu DebnathAnurag BhargavSukriti SinghVikas LunawatSaikanth KMaruthi Prasad BPreeti Sagar NegiAnusha N MNaseeb ChoudhuryPankaj ThakurGuhan V Mohan Krishna Chowdry A
Ashish Khandelwal
Editor-in-Chief
EDITORIAL TEAM
Preeti Sagar Negi
C O N T E N T S
Treasurer
Volume 02 | Issue 05 | MAY 2021
Senior Editor
ROLE OF SECONDARY
METABOLITES IN PLANTS
AGAINST INSECTS
16
DATA MINING – A TOOL OF BIG
DATA FOR SMART
AGRICULTURE
22
ORGANIC FARMING IN
MULBERRY
01
IMMUNOLOGY IN INSECTS04
PLANT SECONDARY
METABOLITES AND INSECTS –
TUG OF WAR
12
SOIL HEALTH AND
SUSTAINABILITY
24
ECOLOGICAL ENGINEERING: A
NEW STRATEGY FOR PEST
MANAGEMENT
27
Article Id:151 - 157
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Article Id:151
ORGANIC FARMING IN MULBERRY
G. Swathiga and S. Ranjith kumar
Department of Sericulture, Forest College and Research Institute, TNAU, Mettupalayam
Introduction
Organic farming is a sustainable farming system also called natural farming/Bio-farming,
advocated in 1935 by Japanese philosopher Mokichi Okada. Organic farming is a system which
avoids or largely excludes the use of synthetic inputs (such as fertilizers, pesticides, hormones,
feed additives etc.) and to the maximum extent feasible rely upon crop rotations, crop
residues, animal manures, off-farm organic waste, mineral grade rock additives and biological
system of nutrient mobilization and plant protection.
Sericulture is a highly remunerative enterprise commonly practiced in most of the
southern Part of India in which mulberry is cultivated as the food plant for the silkworm. Like
other agricultural crop, mulberry needs proper cultivation package as the foliage is used as the
sole food for silkworm. The quality of mulberry leaf is directly reflects on the quality of
cocoons. Large quantity of leaf biomass is produced by the ruling variety, V I to the tune of 55
to 60MT/ha/year. The requirement of macronutrients viz., NPK is also set to the tune of
350:140:140 kg/ha/year for the variety to explore its full yield potential. Supplementation of
such high quantity of nutrients in terms of chemical fertilizers not only affected the soil health
but also developed pressure on the farmers to face the increased cost of cultivation.
Need of Organic farming
Due to the escalation price on fertilizers and its large quantity requirement, farmers
face problems to maintain the sustainable quality leaf production. In addition to this, the soil
health has deteriorated gradually at great extent due to high application of chemicals and
fertilizers in the mulberry field. Organic farming is a concept by which the required quantity of
nutrients is being supplemented through different naturally available resources.
In mulberry high quantity of leaf biomass is produced and being utilized as feed to
silkworm for the production of quality cocoons. The quantity of chemical fertilizers
recommended for mulberry cultivation is quite high as compared to other agricultural crops.
This leads to increase the cost of cultivation. Fertilizers are not only in short supply but also
expensive and not available in time. In addition, repeated application of chemical fertilizers
leads to soil pollution and depletion in soil microflora. This often becomes a bottleneck in
mulberry cultivation. It is imperative to adopt such an alternate system of cultivation without
chemicals and fertilizers for mulberry which can only address to the above problem and
maintain the sustainable production. It has been proven over the years that, it is possible to get
sustainable mulberry leaf yield with better leaf quality by using biofertilizers of bacteria as well
as fungal origin, compost and vermicompost produced out of seri farm residue and green
manures. However, due to removal of high biomass every year, judicious blend of organic and
inorganic source of nutrients is inevitable.
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Role of Organic farming in mulberry cultivation
Microbes are major agents, which transfer bioproducts and play an important role in
the sustainable crop production. In this situation, farmers can opt bio-resources like sericultural
farm wastes, which have maximum quantity of micro and macro nutrients. Azotobacter
biofertilizer for nitrogen supply, phosphorous solubulizing micro organism and VAM for
maximum uptake of phosphorus and green manuring for improving the soil fertility and
productivity. Infact, FYM/compost has been used since long ago to increase the soil fertility and
productivity.
The major role of organic farming in promoting agriculture was to restore the soil
health through balanced nutrients. Since organic manure is bulky in nature and increases the
water holding capacity and soil porosity, it effectively releases the macro and micro nutrients
slowly as per the requirement. The concerted efforts of many dedicated practitioners of
alternative agriculture like organic, natural and biodynamic farming have shown that it is
possible to achieve good soil fertility with reduced application of chemical fertilizers. This
system would also reduce the cost of farming in addition to maintaining the soil productivity
and also plant and animal health. The same principles can also be followed in mulberry
cultivation for better economic returns, in which quality leaf production for better and more
suitable silkworm cocoon production can be ensured.
VAM* - 100 kg inoculum of Glomous mosseae and Glomous faciculatum has to be
applied in between two rows for established garden (2nd week after pruning). The VAM
mobiles and seriphos (Bacillus megatherium) will soulbilise the phosphorus content
made available through FYM, phosphocompost or vermicompost and green manuring.
To increase the phosphorous content (1.5-2.0%) of sericompost, mussorie rock
phosphate can be incorporated to sericultural farm wastes @ 20 kg per tonne of wastes
during the composting process (Phosphocompost)
Green manuring crops – Sunhemp or Diancha (seed rate 20-25 kg/ha/crop). 80-100 kg
nitrogen, 10-30 kg phosphorus and 10-20 kg potash can be made available through 10-
15 MT of good quality green manure biomass.
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Organic bioresources for organic farming in mulberry production and nutrients
availability
Bioresources Quantity
(kg/ha/yr)
Nitrogen
(kg)
Phosphorus
(kg)
Potash
(kg)
Seri Azo
VAM*
Seriphos
FYM
Vermicompost/Compost
Green manure
Total
23
-
5
10 MT
10 MT
10-15 MT
150-175
-
-
40-50
180-200
80-100
450-525
-
-
-
15-20
90-100
15-30
175-235
-
-
-
20-25
150-200
10-20
210-275
Benefits of the organic package in Sericulture
Enhances the mulberry growth
Higher mulberry leaf yield
Sustainable leaf production
Improved the soil fertility
Maintenance of soil health
Low cost of cultivation
Safe to silkworms
Environment friendly
Conclusion
The use of organic matter in soil fertility management and disease and pest
management, with reduced chemical input, is considered as an eco-friendly alternative to the
use of chemical fertilizers. Organic farming in sericulture has proved to be safe to silkworms,
is farmer friendly, environment friendly, and cost effective. The use of organic sources such as
bio-composting, green manuring, and micro bio-fertilizers, improves mulberry productivity,
soil productivity, and also the leaf quality. It also reduces pest and disease incidence by better
build up of a natural enemy complex. Utilizing abundantly and naturally available organic
resources instead of chemical inputs, such as fertilizers and pesticides, may also help in
practicing an eco-friendly and sustainable sericulture.
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Article Id:152
IMMUNOLOGY IN INSECTS
1Lekha priyanka Saravanan, 2S. Jeyarani and 3T. Sharmitha 1, 3Research Scholar, Department of Agricultural Entomology, Agricultural College and Research Institute, Tamil
Nadu Agricultural University, Coimbatore – 641 003. 2 Professor, Department of Agricultural Entomology, Agricultural College and Research Institute Tamil Nadu
Agricultural University, Coimbatore – 641 003.
Corresponding author: lekhaento.21@gmail.com
Introduction
Immunology in insects deals with the immune response exhibited by insects against
pathogens, parasitoids, pesticides and unfavourable conditions. The sites in insects responsible
for immune response are fat bodies and haemocytes. They comprise of pattern recognition
proteins (PRPs) which recognize the conserved domains of pathogens known as pathogen
associated molecular patterns (PAMPs) and thus immune response is initiated. There are two
types of immune response namely, Humoral immune response and Cellular immune response.
Milestones in insect immunity
The first anti – microbial peptide isolated was cecropia from Hyalophora cecropia by
Boman in the year 1981. A milestone in insect immunity was the study of innate immunity in
Drosophila melanogaster by Hoffman which won him “The Nobel Prize in Physiology”.
Origin of innate immunity in insects
Fat body
The larval fat body consists of small nodules suspended in the hemocoel and distributed
throughout insect body. Majority of proteins of the hemolymph are synthesized in this tissue,
which also serves as lipid, carbohydrate and protein storage sites.
The fat body is a target tissue for all important insect hormones such as neural
hormones, juvenile hormone and ecdysone and is also a site of response to microbial infection.
Immune genes, in the fat body, are induced by microbial infection and encode antimicrobial
peptides which are then released into the hemolymph.
Hemocytes
In insects, there are no blood vessels. Blood and interstitial fluid are indistinguishable
and are collectively referred as hemolymph which bathes all internal tissues, organs and
hemocytes, and facilitates the transport of nutrients, waste products and metabolites. The
most common types of circulating hemocytes are granulocytes and plasmatocytes.
Pattern recognition proteins/receptors
The first step for the initiation of immune response, either humoral or cellular, is the
recognition of the pathogen. This is achieved by the pattern recognition proteins / receptors
(PRPs), that recognize and bind conserved domains (patterns) located on the pathogen surface,
which are called pathogen – associated molecular patterns (PAMPs). These proteins are
present on the plasma membrane of fat body cells and hemocytes or they are soluble in the
hemolymph.
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PRPs bind on lipids and carbohydrates which are synthesized by microorganisms and
are exposed on their surface, such as lipopolysaccharites (LPS) of gram negative bacteria and
peptidoglycans of gram positive bacteria and β – 1,3 – glucans of fungi. The binding of invaders’
PAMPs on PRPs induces the synthesis of antimicrobial proteins or initiates the immune
response, leading to phagocytosis, nodule formation and encapsulation of the invaders.
PRPs PAMPs Initiates
Binds to conserved domains
on the pathogens
Pathogen Associated Molecular
Pattern
Anti microbial Peptides
Present on PM of fat bodies
or haemocytes
Present on the outer surface of
pathogen
Enzyme cascades
Immunolectins Lipopolysaccharide
(LPS)
Phagocytosis or Nodule
formation
Peptidoglycans (PGRP) Gram positive bacteria Toll or IMD pathway
Glucans (GNBP) Glucans (Fungi) and LPS Anti microbial Peptides
Hemolins LPS Phagocytosis
Integrins Not Known Encapsulation
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Humoral immune response
The humoral immune response is based on the products of characterized immune
genes induced by microbial infection and encode antimicrobial peptides, which are synthesized
predominantly in fat body and released into hemolymph. Humoral immune responses also
includes activation of enzymic cascades that regulate coagulation and melanization of
hemolymph, and production of reactive oxygen and nitrogen species (ROS – RNS).
Antimicrobial peptides
Antimicrobial peptides (AMPs) have been isolated and characterized in insects. These
molecules are small, 12 – 50 amino acids, cationic peptides, which bind anionic bacterial or
fungal membranes leading to disruption and cell death.
No Source Anti Microbial Peptides Functions against
1 Toll pathway Defensin Gram positive bacteria
2 IMD pathway Cecropin Gram negative bacteria
3 IMD pathway Drosocin Gram negative bacteria
4 IMD pathway Attacin Gram negative bacteria
5 IMD pathway Diptericin Gram negative bacteria
6 Toll pathway Drosomycin Fungi
7 Toll pathway Metchinowin Fungi
Activation of Toll pathway
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Toll pathway
IMD pathway
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Coagulation of hemolymph
Insects have developed mechanisms for the coagulation of hemolymph, in case of
wounding, to prevent loss of body fluids. In the cockroach Leucophaea maderae, hemocytes
secrete a calcium dependent transglutaminase that catalyzes the polymerization of lipophorins
and vitellogenin – like proteins. According to this, LPS and β – 1 , 3 – glucan trigger a serine
protease chain reaction, finally leading to the coagulation of the hemolymph. The secretion of
preclotting enzymes, melanin derivatives and reactive oxygen species, are toxic invading
pathogens.
Melanization of hemolymph
Melanization, the pathway leading to melanin formation, has a central role in defense
against a wide range of pathogens and participates in wound healing as well as in nodule and
capsule formation. Melanization depends on tyrosine metabolism. Tyrosine is converted to
dopa, an important branch point substrate, by activated phenoloxidase (PO). Dopa may be
either decarboxylated by dopa decarboxylase (Ddc) to dopamine or oxidised by PO to
dopaquinone.
Dopamine is also an important branch point substrate, because dopamine derived
metabolites either via PO or through other enzymes are used in several metabolic pathways,
participating in neurotransmission, cuticular sclerotization, cross – linking of cuticular
components via quinone intermediates, phagocytosis, wound healing and melanization in
immune reactive insects.
Cellular immune response
Cellular responses are performed by hemocytes (plasmocytes and granulocytes) and
include phagocytosis, nodulation, encapsulation and anti – viral response.
Phagocytosis
Phagocytosis initiates with the recognition of the invading pathogens, engulfment and
is completed with their intracellular destruction, by individual hemocytes. In insects,
phagocytosis is achieved mainly by the circulating plasmatocytes or granulocytes, in the
hemolymph. The uptake of a microbe by a phagocytic cell requires multiple successive
interactions between the phagocyte and the pathogen as well as sequential signal transduction
events. Phagocytosis is induced when phagocyte surface receptors, are activated by target
cells. Finally, the pathogen is broken into fine particles and discharged.
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Nodulation
Nodulation refers to multicellular hemocytotic aggregates that entrap a large number
of bacteria. Nodulation occurs in response to a number of invaders. Several haemocyte
aggregates together with the aid of a protein (Noduler) form a large nodule. Within the nodule,
the invading pathogen dies of asphyxiation.
Phagocytosed
pathogen
Sequential
Signal
Transduction
Activation of
receptors
Activation
Phagocytotic
Cell
Activation Pathogen
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Encapsulation
Encapsulation refers to the binding of hemocytes to larger targets, such as parasites,
protozoa, and nematodes. Encapsulation can be observed when parasitoid wasps lay their eggs
in the hemocoel of Drosophila larvae. Hemocytes after binding to their target form a multilayer
capsule around the invader, which is ultimately accompanied by melanization. Within the
capsule the invader is killed, by the local production of cytotoxic free radicals ROS and RNS or
by asphyxiation
Antiviral response
Viruses are intracellular pathogens that infect all forms of life. The first potent antiviral
defense mechanism was identified in plants, through RNA silencing. Recently, RNAi was found
to play an important role in the control of viral infection in Drosophila. This mechanism of gene
silencing depends upon small RNAs that comprises of 21 to 30 nucleotides. The double
stranded RNA which is responsible for the viral infection is cleaved to Small interfering RNA
(SiRNA) by Dicer. This leads to the formation of RISC (RNA Induced Silencing Complex) and
Argonaute (AGO) enzyme. Argonaute is an endonuclease enzyme responsible for the cleavage
of mRNA. Finally the mRNA is silenced by cleavage. Thus, the pathogen responsible for
infection is silenced.
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Conclusion
Insect pathogens and parasitoids are to be tested for their fitness to combat immune
response of insects before commercializing as a potential biopesticide and bio control agent
respectively. RNA silencing acts as a powerful tool to control insect pest and virus. Immune
Priming is possible in few insects. Compounds with no inherent antimicrobial activity (glucan,
LPS) can trigger immune priming and render an insect resistant to a pathogen. Research dealing
with immune priming in productive insects can be intensified. This research will be a milestone
in innovation science. Productive insects must be provided with nutritious diet to stimulate
immune response.
Reference
Lehane, M. J., Wu, D. and Lehane, S. M. (1997). Midgut specific immune molecules are
produced by the blood sucking insect Stomoxys calcitrans. Proceedings of National
Academy of Sciences. 94 : 11502 – 11507.
Sheehan, G., Farrell, G. and Kavanagh, K. (2020). Immune priming: A secret weapon of the
insect world. Virulence, 11(1): 238 – 246.
Tsakas, S. and Marmaras, V. J. (2010). Insect immunity and its signaling: an overview.
Invertebrate survival journal, 228 – 238.
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Article Id:153
PLANT SECONDARY METABOLITES AND INSECTS – TUG OF WAR
Lekha priyanka Saravanan*, I. Padma shree, U. Pirithiraj and T. Sharmitha
Research Scholar, Department of Agricultural Entomology, Agricultural college and Research Institute, Tamil
Nadu Agricultural University, Coimbatore, Tamilnadu – 641 003.
*Corresponding author: lekhaento.21@gmail.com
Mode of Action of plant Secondary Metabolites
Plant secondary metabolites such as alkaloids, nicotine, tubocourarine, ergot alkaloids,
agroclavine, muscarine, caffeine, theobromine, theophylline modulates neuronal signal
transduction.
Terpenes
Secondary metabolites of plants are lipophilic in nature, like monoterpenes,
sesquiterpenes, diterpenes, triterpenes, phenyl propanoids, steroids, and mustards oils.
Further, lipophilic metabolites attack the bio membranes surrounding the living cells and
intracellular compartments. Apart from changing the structure of proteins, these compounds
change the permeability of bio membranes by being trapped inside them.
Phenolics
Phenolics interact with cytoskeleton of the cells, thus interfering with cell division.
However, most of plant secondary metabolites modulate the activity of protein structure.
Among them, majority of phenolic compounds modulate the 3D structure of proteins by
forming multiple hydrogen and ionic bonds with them. Thus affects the metabolism of proteins
in insects.
Alkaloids
Alkaloids are highly toxic to the insect pests. These compounds affect the ion channels,
neurotransmitter receptors, neurotransmitter inactivating receptors, transporters and
enzymes. Modulation of neuronal signal transduction components, plant secondary
metabolites, concentration of neurotransmitters, function of neurotransmitter receptors or
their expression may be altered which may lead to significant changes in the physiology and
behavior of the insect.
Saponins
Saponins contain a lipophilic steroid or triterpene moiety with hydrophobic nature,
form complexes with membrane cholesterol. In addition to the role in modulating neuronal
signal transduction, inhibiting protein synthesis, altering the protein structures, and interacting
with bio membranes, some of the plant secondary metabolites interfere with metabolizing
nucleic acids and enzymes, while some are involved in intercalating the DNA. The intercalation
of DNA by these compounds stabilizes the DNA during the replication process, thus
preventing the activities of helicases and RNA, thereby inhibiting the intermediate steps during
DNA replication.
How do Secondary Metabolites in plants counteract against insects?
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Secondary metabolites serve as protein inhibitors while others alter protein structure
and function. Specific inhibitors, such as colchicine, vinblastine, podophyllotoxin, sanguine,
maytansine and rotenone, inhibit the microtubule assembly necessary for mitotic spindle
assembly during cell division.
Secondary metabolites contain highly reactive functional groups that interact with
amino, sulfhydryl or hydroxyl groups of protein amino acid residues, thereby altering their
structure and functional properties. The frameshift mutations and deletions by plant secondary
metabolites lead to cell death.
Insect Adaptation to Plant Secondary Metabolites
Insects have developed adaptations to toxic plant secondary metabolites through
alterations in the morphological, behavioural and biochemical traits by detoxification,
degradation, excretion and sequestration mechanisms.
Detoxification
A number of enzymes are involved in the detoxification of plant toxins by insect pests.
These toxic secondary metabolites are detoxified or less toxified by insect pests using
detoxifying enzymes. The function of these enzymes depends on host diet composition, insect
species and can involve glycosylation, glutathionation, sulfation or deacylation.
Detoxifying enzymes occur in the cytoplasm of cells and midgut lumen. Metabolism of plant
toxins occurs in cytoplasm and midgut lumen before entering into the cells. Detoxifying
enzymes like cytochrome P450 monooxygenases (P450s), glutathione S – transferases (GSTs),
and carboxylesterases (COEs) are present in insects in low concentrations. Their level
increases when insect feeds on the toxic metabolites. This increased concentration of
detoxifying enzymes converts the toxic metabolites into non – toxic or less toxic form.
Detoxification by P450
P450s are the primarily used by insects against plant allelochemicals. Examples are In
S. frugiperda, the toxic metabolites like 2 – phenylethyl isothiocyanate, indole – 3 – carbinol,
and indole – 3 – acetonitrile are detoxified in insect midgut by P450. In cotton, one of the
important secondary metabolite gossypol is detoxified by P450 monooxygenase. In bark
beetles, Ips pini and Ips paraconfusus plant secondary metabolites such as monoterpenes,
sesquiterpenes, and diterpenoid resin acids are detoxified by P450.
Ips pini Spodoptera frugiperda
Glutathionation
Another important detoxifying enzyme is GST. This process is called as glutathionation.
Detoxification by GSTs occurs in insect midgut, fat body and haemolymph. Detoxification using
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GST has been studied in many lepidopteran insects. Insect GSTs catalyze the conjugation of
glutathione to electrophilic toxic molecules, leading to the formation of water – soluble
glutathione S – conjugates that are easily degraded and eliminated by the insect. In Myzus
persicae, high level of GST was documented. Hence, they were able to feed on brassicaceous
plants with metabolites, glucosinolates and isothiocyanates which can be detoxified by Myzus
persicae.
Myzus persicae
Excretion
Esterases are another group of metabolic enzymes involved in the metabolization of
toxic compounds. Esterases detoxify toxic compounds through enzymatic cleavage or
sequestration of the toxic compounds. The compounds are hydrolyzed into less toxic or non
– toxic polar compounds that are easily excreted from the insect body.
Degradation
UDP Glycosyl Transferases (UGTs) is an important enzyme involved in the degradation
of secondary metabolites. These enzymes catalyze the transfer of a glycosyl group from UDP
– glucose to acceptor molecules. In Manduca sexta, degradation of plant compounds occurs
by UGTs. Gene coding for UGT, BmUGT1 in silkworm, Bombyx mori has been reported to
degrade the flavonoids and coumarins.
Manduca sexta Bombyx mori
Sequestration
Sequestration is defined as the uptake and accumulation of selective and specific toxins
of insect pests, which determines their growth and development. Examples are, In milkweed
bugs (Lygaeinae), cardenolides are tolerated by sequestration. In monarch butterfly Danaus
plexippus, sequestration of cardenolides occurs by target site insensitivity, and the cardenolides
are tolerated by the substitution of valine and histidine in place of leucine and asparagine,
respectively.
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Danaus plexippus Milkweed bug
Conclusion
Biotechnological approaches are also involved in production of secondary metabolites
through genetic engineering process. Recent in vitro experiments also confirm the defensive
roles of secondary metabolites. In the longer run, it will be possible to generate genes which
could be used for production of valuable defensive secondary metabolites in bioreactors or for
metabolic engineering of crop plants. This will improve their resistance against herbivores and
microbial pathogens as well as various environmental stresses. Hence research works can be
to done to commercialize secondary metabolites and use them in crop protection measures.
References
Ali, S. T., Mahmooduzzafar – Abdin, M. Z. and Iqbal, M. (2008). Ontogenetic changes in foliar
features and psoralen content of Psoraleacorylifolia Linn. exposed to SO2 stress. Journal
of Environmental Biology. 29(5): 661 – 668.
Andreotti, C., Ravaglia, D., Ragaini, A. and Costa, G. (2008). Phenolic compounds in peach
(Prunuspersica) cultivars at harvest and during fruit maturation. Annals of Applied Biology.
153: 11 – 23.
Ateyyat, M. (2012). Impact of flavonoids against woolly apple aphid, Eriosoma lanigerum
(Hausmann) and its sole parasitoid Aphelinusmali (Hald.). Journal of Agricultural Science.
24: 227 – 236.
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Article Id:154
ROLE OF SECONDARY METABOLITES IN PLANTS AGAINST INSECTS
Lekha priyanka Saravanan*, T. Sharmitha, I. Padma shree and U. Pirithiraj
Research Scholar, Department of Agricultural Entomology, Agricultural college and Research Institute, Tamil
Nadu Agricultural University, Coimbatore, Tamilnadu – 641 003.
*Corresponding author: lekhaento.21@gmail.com
Introduction
Insects and plants have coexisted over millions of years through the continuous
adaptation of insects to the protective features of the plant. Plants have developed several
morphological and biochemical traits to withstand insect damage. Similarly, insects have
developed several adaptive mechanisms to tolerate and adapt to plant defensive traits. Plants
use a number of morphological, chemical, and biochemical defenses against insect herbivores.
Plants synthesize variety of compounds distinct from the intermediates and products
of primary metabolism called secondary metabolites. Plant secondary metabolites either occur
constitutively in plants or produced in response to insect herbivory. The constitutive secondary
metabolites are known as phyto – anticipins, while the induced ones are known as
phytoalexins. Secondary metabolites are not strictly required for the plant growth and
reproduction but play an important role in the plant defense mechanisms against herbivores,
microbial infections and other roles such as protection from UV radiation.
Apart from line of defense, some of these compounds are utilized by plants to attract
pollinators and seed dispersal. For centuries, Secondary metabolites secretions are used by the
mankind to improve their health, nutrition and enhancing agricultural productivity in a positive
way.
Classification of secondary metabolites
Over 2,140,000 secondary metabolites are known and classified according to their
diversity in structure, function, and biosynthesis. There are three main classes of secondary
metabolites such as
A. Terpenes
B. Phenolics
C. Nitrogen and Sulphur containing compounds.
A. Terpenes
Source: These are synthesized from shikimic acid pathway.
These are the largest group of secondary metabolites derived from acetyl co – A or
glycolytic intermediates. Majority of terpenes produced by plants as secondary metabolites are
involved in defence as toxins, feeding deterrents to insects and mammals. These are further
divided into five subclasses.
A. 1. Monoterpenes
The monoterpene esters that occur in the leaves and flowers of chrysanthemum
species show insecticidal response to insects like beetles, wasps, moths, bees etc. In
gymnosperms like pine and fir, monoterpenes occur in resin ducts, twigs and trunks as α –
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pinene, β – pinene, limonone and myrecene that are toxic to bark beetles, serious pest of
conifer species throughout the world.
A. 2. Sesquiterpenes
A number of sesquiterpene compounds such as costunolides play a vital role in plant
defense which are anti – herbivore agents characterized by five membered lactone rings. They
possess strong feeding repellence to herbivorous insects and mammals.
A. 3. Diterpenes
Abietic acid, a diterpene found in pines and leguminous trees is present in or along with
resins in resin canals of the tree trunk. When these canals are pierced by feeding insects, the
outflow of resin physically block feeding and serve as a chemical deterrent.
A. 4. Triterpenes
Sterols are important component of plant cell membranes, in plasma membrane as
regulatory channels and maintain the permeability to small molecules by decreasing the motion
of fatty acid chains. The milkweeds produce bitter tasting glucosides (sterols) that protect them
against insects and cattle. Azadirachtin, a complex limonoid from Azadirachta indica, acts as a
feeding deterrent to some insects and exerts various toxic effects.
A. 5. Polyterpenes
These are high molecular weight terpenes which occur in plants. The principal
tetraterpenes are carotenoids family of pigments. Other polyterpene is rubber, a polymer
containing 1500 – 15000 isopentenyl units. Rubber is found in long vessels called laticifers,
which provide protection as a mechanism for wound healing and as a defence against
herbivores.
B. Phenolic compounds
Plants produce products that contain a phenol group, which is an important part of the
plant defence system against pests and diseases including root parasitic nematodes.
Source: These are synthesized from shikimic acid pathway.
B. 1. Coumarin
Coumarins are the simple phenolic compounds that are wide spread in the vascular
tissues of plants which play a vital role in various plant defense mechanisms against insect
herbivores, fungi and bacteria. Coumarins are derived from shikimic acid pathway common in
bacteria, fungi and plants but absent in animals. It is suspected that these compounds serve as
natural pesticide defence compounds for plants and constitute a starting point for the discovery
of new derivatives with a range of improved antifungal activity.
B. 2. Furano coumarins
It is a type of coumarin, abundant in the members of umbelliferae responsible for
phytotoxicity. In general, these compounds become toxic when they get activated by light.
Psoraline, basic furano coumarin, is known for its use in the treatment of fungal defence and
found very rarely in SO2 treated plants.
B.3. Lignin
It is a highly branched polymer of phenyl – propanoid groups, formed from three
different alcohols viz., coniferyl, coumaryl and sinapyl which is oxidized by a plant enzyme-
peroxidase to form lignin. The proportion of monomeric units in lignin vary among species,
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plant parts and even on layers of a single cell wall. Due to its physical toughness, herbivorous
animals cannot feed and its chemical durability makes lignin indigestible to herbivores and
insects.
B. 4. Flavonoids
In plants flavonoids play an important role in many biological processes like seed
development and growth, fruit development and ripening, pollen tube germination and
hormone transport. Flavonoids prevent the damage caused by fungi, viruses, bacteria,
herbivores and act as attractants to pollinating animals. They are also responsible for colour
differences in fruits, flowers and seeds. New pesticides are being developed using flavonoids,
as an alternative to synthetic pesticides. Flavonoids can inhibit enzymatic activity and suppress
the growth of feeding larva. Flavonoids like quercetin, rutin, and naringin can be used as an
insecticide in the management of nymphs and adults of the aphid, Eriosoma lanigerum.
B. 5. Tannins
Most tannins have molecular masses between 600 and 3000. Tannins are toxins which
reduce the growth and survivorship of many herbivores and animals. Tanins are the phenolic
polymers with defensive properties. The defensive properties of tannins are generally
attributed to their ability to bind proteins. Tanins are feeding deterrents to many herbivores.
Feeding deterrence is undoubtedly a mechanism of plants to protect against insects. Effects of
tannins on behaviour and physiology of herbivores are influenced by the nutrient profile of
tannins. In mammalian herbivores, they cause a sharp, astringent sensation in the mouth as a
result of their binding of salivary proteins. Mammals such as cattle, deer and apes,
characteristically avoid plant with high tannin contents.
C. Sulphur containing compounds
Sulphur containing compounds include
Glutathione Synthetase (GSH)
Glucosinolates (GSL)
Phytoalexins
Thionins
Defensins and
Lectins
Source: These are synthesized from common amino acids. They play an important role in
governing the defence of plants.
C. 1. GSH (Glutathione Synthetase)
GSH is sulphur containing glucosides which is produced by plants when the plant suffers
sulphur deficiency. This mobile and easily soluble form of sulphur is readily assimilated by plant
to combat sulphur shortage. Thus, it regulates the growth and development of plant. They also
provoke resistance of plants during microbial attack and act as cellular antioxidants during
stress.
C. 2. GSL (Glucosinolates)
GSL is a nitrogen and sulphur containing plant glucosides and are produced by plants
to induce resistance against insect pests. When the plant is subjected to insect attack GSL
breaks down to isothiocyanates which activates the antioxidant defence system in plants. This
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protects the plant against insect damage. Leaves of a Brassica line that was resistant to
Leptosphearia maculans had higher levels of GSL than the susceptible line. Their mode of action
has not yet been well defined.
C. 3. Phytoalexins
Response of plants to bacterial or fungal invasion is the synthesis of phytoalexins. These
are chemically diverse group of secondary metabolites with strong antimicrobial activity that
accumulate around the site of infection. Phytoalexins are generally undetectable in the plant
before infection, but they are synthesized very rapidly after microbial / pest attack. The point
of control for the activation of these biosynthetic pathways is usually the initiation of gene
transcription. Thus, plants do not appear to store any of the enzymatic machinery required for
phytoalexin synthesis. Instead, soon after microbial invasion, they begin transcribing and
translating the appropriate mRNAs and synthesize the enzymes de novo.
Phytoalexin production appears to be a common mechanism of resistance to
pathogenic microbes. Different plant families employ different types of secondary products as
phytoalexins. Examples are in leguminous plants, such as alfalfa and soybean, isoflavonoids are
common phytoalexins, whereas in solanaceous plants, such as potato, tobacco and tomato,
sesquiterpenes are produced as phytoalexins. Examples are Phaseolin in Phaseolus vulgaris and
glyceollins in Glycine max, Pistin in Pisum sativum pods, Ipomeamarone in sweet potato,
Orchinol in orchid tubers and Trifolirhizin in red clover. Sometimes the production of
phytoalexins leads to death of plant cells, known as the hypersensitive response (HR) or
Apoptosis.
C. 4. Defensins
As the name indicates defensins are antifungal and anti – bacterial. These are also
pathogen – inducible and are expressed in higher amounts when subjected to pathogen attack.
C. 5. Thionins
Thionins strengthen the natural defense system of plants against micro – organisms,
insects and mammals. Infected wheat spikes with higher amount of thionins were resistant to
Fusarium culmorum.
C. 6. Lectins
Lectins are defensive proteins that bind to carbohydrate or carbohydrate containing
proteins. After being ingested by herbivores, lectins bind to epithelial cell lining of the digestive
system and disrupt the nutrient absorption.
D. Nitrogen containing compounds
Nitrogen containing compounds include
Alkaloids
Cyanogenic glucosides and
Non protein amino acids
Source: These are synthesized from common amino acids
D. 1. Alkaloids
These are nitrogen containing secondary metabolites present abundantly in vascular tissues of
plants. Alkaloids are abundantly found in dicots compared to monocots and gymnosperms.
These include Pyrolizidine alkaloids (PAs) which serve as defence against microbial infection
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and insect herbivory. They are synthesized from the common amino acids namely aspartic
acid, lysine, tyrosine and tryptophan.
D. 2. Cyanogenic glucosides
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Cyanogenic glucosides are a group of nitrogen containing compounds. When the plant
is subjected to damage, they readily break down to emit volatile poisonous gas HCN and H2S.
When the plant is damaged due to herbivore feeding, the cell contents of different tissues mix
and form HCN. The emission of this gas deters feeding by insects and acts as an Anti – feedant.
The presence of cyanogenic glucosides also repels snails and slugs. Examples are Amygdalin in
seeds of almonds, apricot, cherries and peaches, Dhurin in Sorghum bicolar.
D. 3. Non protein Amino acids
Non – protein amino acids are present in free forms and are mistakenly incorporated
for proteins. They serve as barriers against insect pests. Examples are canavanine and azetidine
are analogues of arginine and proline respectively. These block the uptake of protein amino
acids by insects. Plants that synthesize non – protein amino acid are resistant to herbivorous
animals, insects and pathogenic microbes.
For example, after ingestion, Canavanine binds to the enzyme to which arginine
normally binds. Thus arginine transfer RNA molecule is incorporated with canavanine in place
of arginine. This leads to the formation of a non – functional protein in place of arginine. Thus
the metabolism of arginine in insects is disrupted.
Conclusion
During the last several years, it has been discovered that hundreds of compounds that
plants make have significant ecological and chemical defensive roles, opening a new area of
scientific endeavour called as ecological biochemistry (Harborne, 1989). Therefore, additional
research in area of natural pesticides development is needed in the current scenario.
References
War, A. R. and Sharma, H. C. (2014). Induced resistance in plants and counter – adaptation by
insect pests. Short views on Insect Biochemistry and Molecular Biology. 1 – 16.
Wink, M. (2010). Introduction: Biochemistry, physiology and ecological functions of secondary
metabolites. Annual Plant Reviews. 40: 1 – 19.
Ylstra, B., Touraev, A., Moreno, R. M., Stoger, E., Van, T. and Vicente, O. (1992). Flavonols
stimulate development, germination, and tube growth of tobacco pollen. Plant
Physiology. 100: 902 – 907.
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Article Id:155
DATA MINING – A TOOL OF BIG DATA FOR SMART AGRICULTURE
Baby Akula, Srujana Puppala and Divya N
Data mining is one of the important driver for agriculture development being
multidisciplinary as it merges artificial intelligence, computer science, machine learning,
database management, mathematics algorithms and statistics (Liao, 2003). Data Mining
techniques continue as a key driver of agriculture development in India as it involves analyzing,
extracting and predicting the meaningful information from enormous data. It plays a vital role
in Smart Agriculture for managing real-time data analysis with large volumes of data.
Data mining techniques in smart agriculture are being used mainly for planning soil and
water use, monitoring crops health, optimizing the use of natural resources, limiting the use
of pollutants (e.g. pesticides, herbicides), improving the quality of the production etc. Hence,
research on use of data mining as a tool of big data towards smart agriculture is gaining focus.
Smart farming is an approach of using modern technologies like data mining, big data,
and analytics to enhance the quantity and quality of the agricultural industry. These
technologies can build a decision support system to assist the farmers in smart decision making
which can increase their productivity. Smart Agriculture uses a systematic approach designed
using agricultural big data and data mining techniques to predict and control forecasting of
weather, prediction of crop yield, selection of crop, crop diseases and pest management and
agricultural marketing by a holistic approach comprising various related technology and related
sector’s data. The technologies used for smart agriculture generate large volumes of data,
known as Big Data, e.g., sensors on fields and crops provide granular data points on soil
conditions, as well as detailed information on weather, fertilizer requirements, water
availability and pest infestations. To extract information from these large volumes of data,
we require a new generation of practices known as “Big Data Analytics”. Big data and data
analytics can transform the agriculture by boosting productivity besides innovation, managing
environmental challenges, cost saving, new business opportunities, and better supply chain
management. For example; precise application of manure and irrigation will enhance the
quantity and quality of yield harvesting with minimum intervention of human beings. Such
smart farming also can be operated remotely which can help the farmers.
According to Worldometer, the world population now is more than 7.9 billion which
will be around 9.6 billion by 2050 necessitating agriculture efficiency to increase by 35-70%
and for which technology is the only key. Unfortunately, a 2018 survey stated that the
percentage of workers in the agricultural sector would drop to 25.7% by the year 2050
(http://www. Ibef.org/ economy). The sector is increasingly losing the workforce as the next
generation has been moving to a non-farming occupation for better payment. This
unprecedented trend may cause 4.6 billion people to suffer from food insecurity by 2030 and
only 5 billion middle-income people will only buy enough food. For providing the food for these
people, the agricultural production should be almost doubled within a short period of time,
indeed, a major challenge for humanity.
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Big data is the only way to increase the required food production by using modern
sophisticated technology in every step of agricultural production. Farmers usually take decision
based on their experience and by consulting with other experienced farmers or from technical
expert. But this conventional decision-making process is not accurate and scientific, because
of constantly changing weather and climate condition. It’s a great opportunity for the framers
to move from traditional framing to smart framing by using the latest technologies. Big data
driven agriculture provides opportunity to transform from traditional decision making to data-
based novel decision making with following advantages.
1. Data mining techniques can be used to solve complex soil dataset to improve the
effectiveness and accuracy of classification of the large soil datasets, weather or any
voluminous data sets. In contrast, if statistical techniques are time consuming and highly
expensive and hence data mining tool would gain over statistical techiques
2. Application of data mining techniques can be used for automation and to develop a
decision support system for taking strategic decisions on the agricultural practices , viz.,
right use of fertilizers, irrigation scheduling plans, crop planning, etc for better
production and protection.
3. Can be used for efficient knowledge exploration and knowledge acquisition to
produce optimized results about farm cultivation.
4. Prediction-based data mining models tell revenue and productivity estimation and
reporting to aid in making decisions.
5. Helps in food processing value chains starting from selection of right agri-inputs,
monitoring the soil moisture, controlling irrigations, tracking prices of market, finding
the right selling point and getting the right price.
Other advantages of data mining in smart agriculture are:
Smart greenhouses
Better livestock management
Involvement of agriculture drones for GIS mapping etc.
Limitations and future thrust:
Use of agricultural big data technologies are still at low level affair as it requires more
investment for establishment of infrastructure, training related persons, enhanced
technological knowledge of farmers and awareness about the benefits of big data
Government initiatives, private sector’s involvement and a public-private partnership
are necessary for large scale commercialization.
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Article Id:156
SOIL HEALTH AND SUSTAINABILITY
1G. Karuppusamy*, 2R. Prabhu, 3C. Tamilarasan, 4G. Manikandan 1Ph.D. Scholar, Department of Crop Physiology, TNAU, Coimbatore – 641 003, Tamil Nadu, India 2Teaching Assistant, School of Post Graduate Studies, TNAU, Coimbatore – 641 003, Tamil Nadu, India 3Ph.D. Scholar, Department of Seed Science and Technology,TNAU, Coimbatore – 641 003, Tamil Nadu, India 4Senior Research Fellow, Central Institute of Agricultural Engineering, Regional Centre, Coimbatore – 641 007, Tamil Nadu, India *Corresponding author - karuppusamy627@gmail.com
Abstract
A balanced soil functions as a complex living environment that provides a variety of
environmental resources, including maintaining water quality and plant fertility, regulating soil
nutrient recycling decomposition, and eliminating greenhouse gases from the atmosphere. Soil
health is described as an integrative property that expresses a soil's ability to react to
agricultural activity in order to continue to sustain both agricultural production and the
provision of other ecosystem services. The most difficult aspect of sustainable land
conservation is preserving environmental service delivery while increasing agricultural yields.
It is suggested that soil quality is based on the preservation of four major functions: carbon
transitions, nutrient cycles, soil structure conservation, and pest and disease regulation. Each
of these functions is made up of a set of biological processes carried out by a diverse group of
interacting soil organisms under the influence of the abiotic environment.
Sustainable agriculture is primarily concerned with the land fertility and reducing the negative
impacts of farming activities on the atmosphere, soil, water, ecosystem, and human health.
Reduces the use of non-renewable energy and inputs from petroleum-based goods in favour
of renewable resources.
Introduction
Soil health is characterised as "the capacity of soil, within ecological and land-use
boundaries, to act as a vital living system to preserve plant and animal production, retain or
improve water and air quality, and promote plant and animal health." A soil's health is one of
its most important characteristics. It is known as a set of characteristics that characterise and
classify its fitness. Soil content, on the other hand, is an extrinsic property of soils that varies
according to the intended use of that soil by humans. It may be related to farm production and
wildlife support, watershed protection, or recreational outputs. Sustainable agriculture has
been described as an alternative integrated approach for addressing both fundamental and
applied issues in food production in an environmentally friendly manner. It combines biological,
physical, chemical, and ecological concepts to create modern environmentally friendly
activities. Furthermore, sustainability has the potential to assist in meeting global food
agriculture needs. Soil microorganisms (mostly bacteria and fungi) can convert nitrogen (N)
from organic to inorganic forms, affecting plant mineral absorption, composition, and
productivity. Microbial communities play an important role in fundamental processes that
ensure the stability and productivity of agro-ecosystems.
Soil Biodiversity and Sustainability
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The term "soil biodiversity" refers to all species that live in the soil. Soil biodiversity is
characterised by the Convention on Biological Diversity as "variation in soil life, from genes to
ecosystems, and the ecological complexes of which they are a member, ranging from soil
microhabitats to landscapes." Soil microorganisms bind roots to soil, recycle nutrients,
decompose organic matter, and react rapidly to changes in the soil biome, serving as reliable
markers for particular soil functions. Microbial population functions and their interactions with
soil and plant may provide a long-term soil ecological environment that supports crop growth,
production, and yields. As a result, studying the functions, behaviour, and communication
mechanisms of microbial communities in soil and plants is important for preventing unintended
management activities until they do irreversible harm to the agro-ecosystem. Understanding
microbial activities, in particular, can provide consistent diagnostics of long-term soil health and
crop quality. Dense population use, climate change, and depletion of aboveground habitats, as
well as overgrazing, soil organic matter depletion, deforestation, crop erosion, and land
destruction, were all stressors on soil biodiversity. As a result, recognising threats to soil
biodiversity and intervening to protect it is crucial for global agricultural sustainability.
Decomposition, nitrogen cycling, and population control are examples of collective soil
characteristics and processes. Overall, microbial communities' functional capacities in the soil
for nutrient acquisition, mobilisation, fixation, recycling, decomposition, depletion, and
remediation are linked to soil quality and agricultural sustainability.
Soil Health Components for Sustainable Agriculture
The concepts "soil health" and "soil quality" were used as indicators of soil condition,
and their evaluation aimed to track the impact of current, historical, and future land use on
agricultural sustainability. Soil salinization, acidification, compaction, crusting, fertiliser
depletion, loss in soil biota biodiversity and biomass, water mismatch, and disturbance of
elemental cycling are all examples of unsuitable farming activities that degrade soil quality. The
most common biological indicator candidates were: Soil microbial taxa and community
structure, Soil microbial community structure and biomass, Soil respiration, Multi-enzyme
profiling, Nematodes, Micro arthropod, Soil fauna and flora, Soil invertebrates, Microbial
biomass. Overall, defining soil health components is critical for the effective implementation of
national and global agricultural monitoring systems, as well as the long-term viability of our
agricultural systems. Pathogens are suppressed, biological activities are sustained, organic
matter is decomposed, radioactive materials are inactivated, and nutrients, resources, and
water are recycled in healthy soil. Soil quality is a term that refers to the biological
characteristics and functions of soil, as well as their interactions with chemical and physical
properties. Organic farming is becoming increasingly popular as the most productive
agricultural method because it increases not only physical, biological, and environmental
services such as soil nutrient mineralization, microbial activity, abundance and diversity, and
groundwater quality, but also yield and product quality.
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Conclusion
Soil health assessment is based on soil quality variables that guarantee sustainability of
crop production in agricultural lands. Improved soil health indicators are needed to better
understand how production strategies and environmental factors affect the physical, biological,
and chemical stability and dynamics of soil-rhizosphere-plant systems, as well as their impact
on short- and long-term sustainability.
References
Kibblewhite, M. G., Ritz, K., & Swift, M. J. (2008). Soil health in agricultural systems.
Philosophical Transactions of the Royal Society B: Biological Sciences, 363(1492), 685-
701.
Leskovar, D., Othman, Y. Organic and conventional farming differentially influenced soil
respiration, physiology, growth, and head quality of artichoke cultivars. J. Soil Sci. Plant
Nutr. 2018, 18, 865–880.
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Article Id:157
ECOLOGICAL ENGINEERING: A NEW STRATEGY FOR PEST MANAGEMENT
Lekha Priyanka Saravanan*, U. Pirithiraj, T. Sharmitha and I. Padma Shree
Research Scholar, Deparment of Agricultural Entomology, Agricultural College and Research Institute, Tamil
Nadu Agricultural University, Coimbatore - 641 003.
*Corresponding author: lekhaento.21@gmail.com
Ecological Engineering
Ecological Engineering is the manipulation of agricultural area and surrounding
environment with the aim of conserving or augmenting the population of natural enemies.
Ecological Engineering is also called as Habitat manipulation. It is a form of conservation
biological control. It involves altering the cropping system to augment or enhance the
effectiveness of natural enemies.
Aim of Ecological Engineering
Ecological engineering paves a new path to use ecology and engineering together to
predict, design and manage the ecosystems. The aim of Ecological Engineering to improve the
living conditions for natural enemies within the agro ecosystem by introducing resources
needed for the fulfillment of their vital requirements which are denoted as SNAP (Shelter,
Nectar, Alternative prey and Pollen).
Plants providing food in the form of nectar and pollen, additional insect pest as prey,
breeding sites, shelter to protect the natural enemies from adverse weather conditions and
overwintering sites are provided to natural enemies through Ecological Engineering.
Techniques of Ecological Engineering
Limited and Selective use of pesticides
Alternate food source
Right diversity
Refugia
Microclimate
Alternate host / Prey insect
Behavioral manipulation
Alternate food source
Some parasitoids obtain needed resources from host while others require access to
non-host foods. Provision of floral nectar to parasitoids can result in increased rates of
parasitism.
Attractant crops
Attractant crops such as Mustard, Sunflower, Carrot, Marigold, French bean, Maize
and Cowpea act as rich pollen and nectar source to attract natural enemies. Vineyard with
buckwheat ground cover attracted leaf roller parasitoids (Gurr et al., 2004).
Repellent crops
Repellent crops repel the insect pests. Mint repels Cabbage moth, Garlic repels
Beetles, Aphids, Weevils, Spider mites and Carrot fly.
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Trap crops
Trap crop is used to attract the insect pests towards it thus protecting the main crop
from pest. Eg: Castor acts as trap crop for tobacco caterpillar in Cotton and Chilli.
Right diversity (Different cropping systems)
Border cropping
Maintenance of necessary host in the off season will conserve natural enemies. Planting
of flowering crops such as Marigold, Bitter gourd, Sesame was found to conserve and enhance
the predators and parasitoids of rice ecosystem.
Weed species such as Echinochloa colonum and Echinochloa crusgalli grown as border
crops in rice ecosystem were found to enhance the activity of predatory mirid bug,
Cyrtorhinus lividipennis which mitigated rice brown plant hopper, Nilaparvata lugens
(Chandrasekar et al., 2017).
Cowpea as border crop in rice ecosystem increased the population density of the BPH
predator, Coccinella septumpunctata (Chanadrasekar et al., 2016).
Inter cropping
Green gram as intercrop and okra as border crop in cotton field attracted
maximum number of spiders and coccinellids that predate on cotton whiteflies
(Muthukrishnan et al., 2015).
Refugia (Provision of artificial shelters)
A section of agricultural land (near crop fields) used as entomophagus park, an area free
of pesticide was found to conserve and enhance the natural enemy population by providing
nectar and pollen source, physical refuge, alternate host, alternate prey, mating sites.
Cyanodon dactylon, Echinochloa crusgalli, Solanum nigrum, Amaranthus viridis,
Cassia occidentails, Litchi, Chrysanthemum, Trifolium repens were found to be the promising
plant sources attracting natural enemies in entomophage park. Specifically, Chrysopids were
found to be attracted to garden sorrel, Trichogrammatids and Ichneumonids were attracted
to Coriandrum sativum, Punica granatum, Cotesia plutella was attracted to Amaranthus,
Eribous and Chelonus were attracted to Nicotiana. A substantial reduction of tobacco
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hornworms was achieved by predaceous Polistes wasps following the erection of nesting
shelters near field margins.
Micro climate
Generally bare soils are unfavorable for many natural enemies because of high
temperature, low relative humidity and low soil moisture. Growing rye grass (Lolium
multiflorum) helps in reducing the temperature of the soil surface in maize (zea mays) fields,
thereby increasing the survival of Trichogramma brassicae.
Alternate host / Prey insect
Colonization of alternate insect hosts may improve synchronization between pests and
its natural enemies. Alternate host of natural enemies can also be made available through
vegetation diversity in vegetation.
Higher parasitism of Acherontia styx eggs on sesame by Trichogamma chilonis in cotton
– sesame intercropping. Collection and rearing of H. armigera eggs from cotton plants in
intercropping revealed higher parasitization by T. chilonis whereas no parasitism was observed
in pure cotton crop.
Behavioural manipulation
Habitat manipulation approaches
Top down control
Here herbivores (second trophic level) are suppressed by the natural bio-agents (third
trophic level) and this type of approach is seen in ‘Augmentive biological control’
Bottom up control
In this approach, manipulation with in crop, such as green mulches and cover crop (first
trophic level) will act on pests directly. This type of approach is seen in habitat manipulation of
‘Conservation biological control’.
Push Pull Strategy
Maize fall armyworm is controlled effectively by push pull strategy. Maize is inter
cropped with Cumbu Napier grass and Desmodium.
Push – Volaties emitted by Desmodium pushes (repels the moth) and attracts the
natural enemies
Pull – Volatiles emitted by Cumbu Napier pulls (attracts the moth to lay eggs) and Maize
is prevented from egg laying by moths of Fall armyworm
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Conclusion Ecological engineering helps to design sustainable cropping systems so that natural
enemies keep pests within acceptable bounds.
References
Gurr, G. M., Wratten, S. D. and Altieri, M. A. (2004). Ecological engineering: a new direction
for agricultural pest management. AFBM Journal, 25 – 31.
Muthukrishnan, N., Ananthraj, B., and Jayaraj, J. (2015). Developing polyculture based
ecological engineering methods in cotton for enhancing predators for the management
of whiteflies. In Proc., of the International Conference on Innovative Insect Management
Approaches for Sustainable Agro – ecosystem Tamil Nadu Agricultural University, AC and
RI, Madurai ,138 – 141.
Chandrasekar, K., Muthukrishnan, N., and Soundararajan, R. P. (2017). Ecological engineering
cropping methods for enhancing predator, Cyrtorhinus lividipennis (Reuter) and
suppression of planthopper, Nilaparvata lugens (Stal) in rice – weeds as border cropping
system. Journal of Pharmacognosy and Phytochemistry, 6(5), 2387 – 2391.
Chandrasekar, K., Muthukrishnan, N., Soundararajan, R. P., Robin, S., and Prabhakaran, N. K.
(2016). Ecological engineering cropping method for enhancing predator Coccinella
septempunctata and suppression of planthopper, Nilaparvata lugens (Stal) in
Rice. Advances in Life Sciences, 5(16), 1288 – 1294.
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