Volume 02 Issue 05

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

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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

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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

www.aiasa.org.in | May 2021 I Vol 2 I Issue 05 | 1

AGRI MIRROR : FUTURE INDIA ISSN: 2582-6980

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.



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.



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.



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: [email protected]

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.

mailto:[email protected]



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



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



Toll pathway

IMD pathway



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.



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



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.



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.



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: [email protected]

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?




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



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.



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.



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.


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 –




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,



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



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



and insect herbivory. They are synthesized from the common amino acids namely aspartic

acid, lysine, tyrosine and tryptophan.

D. 2. Cyanogenic glucosides



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.



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.

https://www.ibef.org/economy/economic-survey-2018-19

http://www/



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.



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 - [email protected]

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




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.



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.



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.


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.



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



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



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.

Documents

Volume 02 Issue 05