agricultural entomology definitions · agricultural entomology definitions parasites - an organism...

AGRICULTURAL ENTOMOLOGY

Definitions

➢ Parasites - An organism that is dependent for some essential metabolic factor on another throughout its all life stages

➢ Parasitoid - An insect parasite of an arthropod that is parasitic in its immature stage, killing the host in the process of development and adults are free living

➢ Predators - Predators are free living organisms, feed their prey, devouring them completely and rapidly

➢ Insects are poikilothermic- do not have mechanism to regulate body temperature which depends on environmental conditions

➢ Crepuscular - Some insects are active during dawn and dusk. eg. Mosquitoes ➢ Integrated pest Management (FAO) - a pest management system- considering

population dynamics of the pest and its associated environment- utilises all suitable management methods – to maintain pest population < EIL

➢ General equilibrium position (GEP) - The average density of a population over a long period of time, in the absence of permanent environmental changes

➢ Economic threshold level (ETL) - Population density at which control measure should be implemented to prevent an increasing pest population from reaching the ETL- Provides sufficient time for control measures. [Always ETL < EIL]

➢ Economic injury level (EIL) - The lowest population density that will cause economic damage

➢ Damage boundary (DB) - The measurable lowest level of damage

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Categories of insect pest

Category Criteria Examples

Based on occurrence

1. Regular pest occur more frequently, close association with the crop

Cardamom capsule borer, Brinjal shoot and fruit borer, Chilli and cardamom thrips, Codling moth, Mango nut weevil

2. Occasional pest Occurs infrequently, no close association with crop

Mango stem borer, Castor slug, Rice caseworm, Rice BPH

3. Seasonal pest Occurs during a particular season every year

Red hairy caterpillar on groundnut, Mango hoppers

4. Persistent pest Occur throughout the year and is difficult to control

Chilli thrips, mealy bug on guava

5. Sporadic pest occurs in isolated localities during some period, GEP < EIL

Coconut slug caterpillar, Sugarcane pyrilla, White grub, Hairy caterpillar

Based on level of infestation

6. Epidemic pest Sudden outbreak in a severe form in a region at a particular time

BPH in Tanjore, RHC in Madurai, Pollachi

7. Endemic pest Occur in a low level in few pockets, regularly and confined to particular area

Rice gall midge in Madurai, Mango hoppers in Periyakulam

Based on ETL and EIL

8. Major pest GEP lies very close to EIL, can be managed by repeated sprays (cause >10% economic damage)

Cotton jassid, Rice stem borer

9. Minor pest Usually GEP < EIL (cause >10% economic damage)

Rice hispa, Ash weevils

10. Key pest Always GEP > EIL, persistent pests, environment must be changed to bring GEP below EIL

Cotton bollworm, Diamond back moth

11. Potential pest Not a pest at present, GEP < EIL If environment changed may cause economic

Spodoptera litura on cotton, wheat armyworm


SURVEY AND SURVEILLANCE OF INSECT PESTS AND FORECASTING

1. Pest monitoring o Monitoring phytophagous insects and their natural enemies is a fundamental tool in

IPM - for taking management decision o Monitoring - estimation of changes in insect distribution and abundance

- information about insects, life history - influence of biotic and abiotic factors on pest population

2. Pest surveillance - constant watch on the population dynamics of pests - its incidence - damage on each crop - fixed intervals - to forewarn the farmers to take up timely crop protection measures.

3. Three basic components of pest surveillance Determination of

4. Pest Forecasting and outbreak based on information obtained from pest surveillance It is useful to predict the suitable stage at which control measure gives maximum protection

5. Types of pest forecasting a. Short term forecasting - Based on 1 or 2 seasons b. Long term forecasting - Based on affect of weather parameters on pest

6. Objectives of Pest Surveillance o to know existing and new pest species o to assess pest population and damage at different growth stage of crop o to study the influence of weather parameters on pest o to study changing pest status (Minor to major) o to assess natural enemies and their influence on pests o effect of new cropping pattern and varieties on pest

7. Survey o To study the abundance of a pest species o Two types of survey - Roving survey and fixed plot survey o Roving survey: Assessment of pest population/damage from randomly selected spots

representing larger area in short period - provides information on pest level over large area

o Fixed plot survey: Assessment of pest population/ damage from a fixed plot selected in a field recorded periodically from sowing till harvest.

o Qualitative survey: For detection of pest


the level of incidence of the pest species the loss caused by the incidence the economic benefits, the control will provide

o Quantitative survey - for enumeration of pest

8. Sampling Techniques o Absolute sampling- To count all the pests occurring in a plot o Relative sampling- To measure pest in terms of some values which can be compared

over time and space e.g. Light trap, Pheromone trap

9. Methods of sampling o In situ counts - Visual observation on number of insects on plant canopy o Knock down - Collecting insects from an area by removing from crop and counting o Netting- Use of sweep net for hoppers, odonates, grasshopper o Norcotised collection - Quick moving insects anaesthesised and counter o Trapping

- Light trap - Positively phototropic insects - Pheromone trap - Species specific - Sticky trap - Sucking insects - Bait trap - Sorghum shootfly - Fishmeal trap - Emergence trap - For soil insects - Water trap – BPH, GLH

o Crop samples- Plant parts removed and pest counted e.g. Bollworms

INTEGRATED PEST MANAGEMENT

1. CULTURAL CONTROL Manipulation of cultural practices to the disadvantage of pests.

Techniques Pest can be managed

Puddling Rice mealy bug

Trimming and plastering Rice grass hopper

Pest free seed material Potato tuber moth

Destruction of weed hosts Citrus fruit sucking moth

Destruction of alternate host Cotton whitefly

Flooding Rice armyworm

Trash mulching Sugarcane early shoot borer

Pruning / topping Rice stem borer

Intercropping Sorghum stem borer

Trap cropping Diamond back moth

Water management Brown planthopper

Judicious application of fertilizers Rice leaf folder


2. PHYSICAL CONTROL Modification of physical factors in the environment to minimise (or) prevent pest problems. Use of physical forces like temperature, moisture, etc. in managing the insect pests.

A. Manipulation of temperature o Sun drying the seeds to kill the eggs of stored product pests. o Hot water treatment (50-55oC for 15 min) against rice white tip nematode. o Flame throwers against locusts. o Burning torch against hairy caterpillars. o Cold storage of fruits and vegetables to kill fruitflies (1-2oC for 12-20 days).

B. Manipulation of moisture o Alternate drying and wetting rice fields against BPH. o Drying seeds (below 10% moisture level) affects insect development.

C. Manipulation of light o Treating the grains for storage using IR light to kill insects (eg.) IR seed treatment unit o Providing light in storage go downs as the lighting reduces the fertility of Indian meal

moth

D. Manipulation of air o Increasing the CO2 concentration in controlled atmosphere of stored grains to cause

asphyxiation in stored product pests.

E. Use of irradiation o Gamma irradiation from Co60 is used to sterilize the insects in laboratory which

compete with the fertile males for mating when released in natural condition. (eg.) cattle screw worm fly, Cochliomyia hominivorax control in Curacao Island by E. F. Knipling.

F. Use of greasing material o Pulses with vegetable oils to prevent the oviposition and the egg hatching by bruchids

G. Use of visible radiation o Yellow colour preferred by aphids, cotton whitefly: yellow sticky traps.

H. Use of Abrasive dusts o Red earth treatment to red gram: Injury to the insect wax layer of storage insect pests o Activated clay : Injury to the wax layer resulting in loss of moisture leading to death.

It is used against stored product pests o Drie-Die : This is a porous finely divided silica gel used against storage insects

Synchronized sowing : Dilution of pest infestation

(eg) Rice, Cotton

Crop rotation Breaks insect life cycle


3. MECHANICAL CONTROL Use of mechanical devices or manual forces for destruction or exclusion of pests.

A. Mechanical destruction : Life stages are killed by manual (or) mechanical force. o Hand picking the caterpillars o Beating: Swatting housefly and mosquito o Sieving and winnowing: Red flour beetle (sieving) rice weevil (winnowing) o Shaking the plants: Passing rope across rice field to dislodge caseworm and shaking

neem tree to dislodge June beetles o Hooking: Iron hook is used against adult rhinoceros beetle o Crushing: Bed bugs and lice

B. Mechanical force o Entoletter: Centrifugal force - breaks infested kernels - kill insect stages - whole

grains unaffected - storage pests. o Hopper dozer: Kill nymphs of locusts by hording into trenches and filled with soil. o Tillage implements: Soil borne insects, red hairy caterpillar. o Mechnical traps: Rat traps of various shapes like box trap, back break trap, wonder

trap, Tanjore bow trap.

C. Mechanical exclusion- Mechanical barriers prevent access of pests to hosts o Wrapping the fruits: Covering with polythene bag against pomegranate fruit borer. o Banding: Banding with grease or polythene sheets - Mango mealybug. o Netting: Mosquitoes, vector control in green house. o Trenching: Trapping marching larvae of red hairy caterpillar. o Tin barrier: Coconut trees protected with tin band to prevent rat damage.

Appliances used in controlling the pests o Light traps: Most positively phototrophic insects are attracted towards light in night o Incandescent light trap: small amount of ultraviolet, considerable visible especially

rich in yellow and red o Mercury vapour lamp light trap: They produce primarily ultraviolet, blue and green

radiation with little red. (eg.) Robinson trap o Black light trap: Flying insects are attracted and when they come in contact with

electric grids, become electrocuted and killed. Eg Pest-O-Flash, Keet-O-Flash o Pheromone trap: Synthetic sex pheromones are placed in traps to attract males. o Yellow sticky trap: Cotton whitefly, aphids, thrips prefer yellow colour. Yellow

colour is painted on tin boxes and sticky material like castor oil / vaseline is smeared on the surface

o Bait trap: Attractants placed in traps are used to attract the insect and kill them. (eg.) Fishmeal trap- to attract sorghum shootfly using Moistened fish meal and DDVP

o Probe trap: Probe trap is used by keeping them under grain surface to trap stored product insect

o Emergence trap: The adults of many insects which pupate in the soil can be trapped by using suitable covers over the ground.


4. HOST PLANT RESISTANCE (HPR) Those characters that enable a plant to avoid, tolerate or recover from attacks of insects under conditions that would cause greater injury to other plants of the same species.

Mechanisms of host plant resistance 1. Antixenosis (non-preferred morphological characters for feeding, oviposition or shelter) o Trichomes in cotton - resistant to whitefly o Wax bloom on crucifer leaves - deter feeding by DBM o Plant shape and colour also play a role in non preference o Open panicle of sorghum - Supports less Helicoverpa

2.Antibiosis - (Adverse effect of the host plant on survival, development and reproduction of insects)

Physical factors in antibiosis - thick cuticle, glandular hairs, silica deposits, tight leaf sheath

Chemical factors in antibiosis

3. Tolerance- Ability of host plant to withstand insect population o Tolerant varieties have high ETL - require less insecticide o Apply less selection pressure on pests. Biotype development is less

Examples for HPR in IPM o Predatory activity of mirid bug Cyrtorhinus lividipennis on BPH was more on a

resistant rice variety IR 36 than susceptible variety IR 8 o Insects feeding on resistant varieties are more susceptible to virus disease (NPV)

Examples of resistant varieties in major crops

S. No Chemicals factors of antibiosis Imparts resistance against

1. DIMBOA Against European corn borer, Ostrinia nubilalis

2. Gossypol (Polyphenol) Helicoverpa armigera (American bollworm)

3. Sinigrin Aphids, Myzus persicae

4. Cucurbitacin Cucurbit fruit flies

5. Salicylic acid Rice stem borer

Crop Insect Pest Resistant varieties

Rice Yellow stem borer TKN 6, Paiyur 1

Brown planthopper (BPH) CO 42, IR 36, IR 64

Green leaf hopper (GLH) IR 50, Ptb 2, CO 46

Sugarcane Early shoot borer (ESB) CO 312, CO 421, CO 661,

Internode borer CO 975, CO 7304


5. LEGAL CONTROL METHODS Preventing the entry and establishment of foreign plant and animal pest in a country or area and eradication or suppression of the pests established in a limited area through compulsory legislation or enactment

1. Pests Accidentally Introduced Into India o Pink bollworm - Pectinophora gossypiella o Cotton cushion scale - Icerya purchasi o Wooly aphid of apple - Aphelinus mali o SanJose scale - Quadraspidiotus perniciosus o Potato tuber moth - Gnorimoschima operculella o Subabul psyllid - Heteropsylla cubana o Spinalling whitefly - Aleyrodicus disperses o Cyst (Golden) nematode of potato - Globodera sp. o Bunchytop disease of banana o Giant african snail - Acatina fullica

2. Foreign Pests From Which India is Free Mediterranean fruitfly - Ceratitis capitata, Grapeavine phylloxera, Cotton boll weevil - Anthonomos grandis and Codling moth of apple - Lasperysia pomonella Quarantine - Isolation to prevent spreading of infection

3. Plant Quarantine -Legal restriction of movement of plant materials between countries and between states within the country to prevent or limit introduction and spread of pests and diseases in areas where they do not exist

4. Pest Legislations o 1905 - ‘Federal Insect Pest Act’ - first Quarantine act against SanJose scale o 1912 - ‘US Plant Quarantine Act’ o 1914 - ‘Destructive Insects and Pests Act’ of India (DIPA) o 1919 - ‘Madras Agricultural Pests and Diseases Act’

Top shoot borer CO 745, CO 6515

Cotton American bollworm Abhadita

Spotted bollworm Deltapine

Stem weevil MCU 3, Supriya

Leaf hopper MCU 5, K 7, K 8

Sorghum Earhead bug K tall

Jasmine Eriophyid mite Pari Mullai

Apple Apple wooly aphid Golden delicious, Northern spy

Bhendi Whiteflies Parbhani kranti


o 1968 - ‘The Insecticides Act’

5. Different Classes of Quarantine 5.1 Foreign Quarantine (Legislation to prevent the introduction of new pests, diseases and weeds from foreign countries)

- Plant quarantine inspection and treatments at sea ports of Mumbai, Kolkata, Cochin, Chennai and Visakapattinam and airports of Amritsar, Mumbai, Kolkata, Chennai and New Delhi

- Import by post parcel prohibited except by scientists - Import of plant materials prohibited or restricted - Import permits required for importation of plant material - Phytosanitary certificate from the country of origin is required

Phytosanitary certificate is issued by State Entomologist and Pathologists to the effect that the plant or seed material is free from any pest or disease

Restriction imposed on the importation of i. Sugarcane setts - to prevent West Indies sugar weevil ii. Coffee seeds - to prevent coffee berry borer iii.Cotton seeds - to prevent cotton boll weevil a. Export of pepper, cardamom and tamarind restricted b. In 1946, Directorate of Plant Protection, Quarantine and Storage, Government of

India established - for inspection of export and import of agricultural commodities.

5.2. Domestic quarantine (within different parts of country) - Flutted scale Icerya puchasi noticed in Nilgiris and Kodaikanal in 1943 in Wattle

trees. Quarantine stations at Mettupalayam and Gudalur for Nilgiris and Shenbaganur for Kodaikanal to prevent spread of flutted scale in TN.

- Preventing movement of Banana from Palani hills to prevent Bunchy top spread

5.3. Legislation to take up effective measures to prevent spread of established pests - Example: Cotton stem weevil, Groundnut RHC, Coffee stem borer, Coconut black

headed caterpillar (BHC), Sugarcane top borer. i. Stem weevil of cotton (Combodia cotton, 1913)

- Previous crop to be removed before Aug.1 - Next crop to be sown not before Sep. 1 to keep land free of cotton for sometime

ii. RHC of groundnut (1930) - Collection of pupae in summer ploughing - Putting light traps and bonfires - Hand picking of egg and larvae - Spread leaves in field, trench, collect and destroy

iii. Stem borer of coffee (1946) - This act is still in force in Salem, Coimbatore, Madurai and Nilgiris - All infested plants to be removed and destroyed by 15th December every year - Swabbing with wettable powder (Carbaryl) on stem and branch


6. THE INSECTICIDES ACT, 1968 (Insecticides Rule, 1971) Statutory bodies

(i) Central Insecticides Board (CIB) (28 members) Chairman (CIB) - Director General of Health Services (ii) Registration Committee (RC) (5 members) Chairman (RC) - Deputy Director General, Crop Sciences, ICAR

Salient features of the insecticides act (1968) - Compulsory registration with CIB (Central level) - Licence for manufacture, formulation and sale at state level - RC to lookafter registration aspects of insecticides

Role of Plant Quarantine in the Export of Agricultural Commodities - International Plant Protection Convention (1951) of FAO, UN. - Article V of the convention makes it mandatory for member countries to issue

Phytosanitory certificate (PSC)

6. SEMIOCHEMICALS IN INSECT PEST MANAGEMENT Substances that mediate communication between organisms o Semiochemicals are classified into Pheromones (intraspecific semiochemicals) and

Allelochemics (interspecific semiochemicals)

I. Pheromones ∗ Chemicals secreted into the external environment by an animal -elicit a specific

reaction in a receiving individual of the same species. ∗ Pheromones are exocrine in origin (i.e. secreted outside the body). Also called as

ectohormones ∗ Based on the responses elicited pheromones can be classified into 2 groups

- Primer pheromones: They trigger off a chain of physiological changes in the recipient without any immediate change in the behaviour.

- Releaser pheromones: These pheromones produce an immediate change in the behaviour of the recipient. They can be successfully used in pest management programmes. Releaser pheromones subdivided as follows.

1. Sex pheromones • Released by one sex only and trigger behaviour patterns in the other sex that facilitate

in mating. They are most commonly released by females but may be released by males also.

• Sex pheromone producing male insects are Cotton boll weevil- Anthonomas grandis, Cabbage looper- Trichoplusia ni and Mediterranean fruitfly- Ceratitis capitata

Examples of female sex pheromones identified in insects

Sl. No. Name of the Insect Pheromone

1. Silkworm, Bombyx mori Bombykol

2. Gypsy moth, Porthesia dispar Gyplure, disparlure

3. Pink bollworm ,Pectinophora gossypiella Gossyplure

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Pest Management with Sex Pheromones Synthetic analogues of insect sex pheromones used in pest management in 3 different ways

a) In sampling and detection (Monitoring) b) To attract and kill (Mass trapping) c) To disrupt mating (Confusion or Decoy method)

2. Aggregation pheromone - Substance produced by one sex will attract both sexes together for feeding and mating - Eg. Synthetic analogue- Ferrulure- attract Red palm weevil and Rhinolure – attract

coconut Rhinoceros beetle

3. Alarm pheromone and trial marking pheromone

II. Allelochemicals Non nutrient substances originating from one organism affect the behaviour and

physiology of other species ➢ Allomone- Benefit to releaser ➢ Kairomone - Benefit to the receiver ➢ Synomone - benefit to both releaser and receiver ➢ Apneuomone - Substance emitted by non living material attract an organism but

detrimental to the another organism living on that material

7. INSECT GROWTH REGULATORS (IGRs)

o Compounds interfere with the growth, development and metamorphosis of insects- IGR

o IGRs include synthetic analogues of insect hormones such as ecdysoids and juvenoids and non-hormonal compounds such as precocenes (Anti JH) and chitin synthesis inhibitors.

o Natural hormones of insects

1. Brain hormone (activation hormone (AH)) o BH is secreted by neuro secretory cells (NSC) of central nervous system (CNS) o It activate the corpora allata to produce juvenile hormone (JH).

2. Juvenile hormone (JH) o It is secreted by corpora allata o Their role is to keep the larva in juvenile condition. o JH I, JH II, JH III and JH IV have been identified in different groups of insects o The concentration of JH decreases as the larva grows and reaches pupal stage.

4. Cabbage looper, Trichoplusia ni Looplure

5. Tobacco cutworm, Spodoptera litura Spodolure, litlure

6. Gram pod borer, Helicoverpa armigera Helilure

7. Honey bee queen, Apis sp. Queen’s substance


o JH I, II and IV are found in larva while JH III is found in adult insects - important for development of ovary in adult females

3. Ecdysone (Moulting hormone (MH)) o It is a steroid and is secreted by Prothoracic Glands (PTG) o Moulting in insects is brought about only in the presence of ecdysone o Ecdysone level decreases and is altogether absent in adult insects.

IGRs used in Pest management a) Ecdysoids

o Synthetic analogues of natural ecdysone. When applied in insects, kill them by formation of defective cuticle resulting in integument lacking scales or wax layer

b) Juvenoids (JH mimics) o Synthetic analogues of Juvenile Hormone (JH). They are most promising as hormonal

insecticides. JH mimics were first identified by Williams and Slama (1966) as paper factor’ or ‘juvabione’ from the wood pulp of balsam fir tree (Abies balsamea) against Pyrrhocoris bug

o Juvenoids have anti-metamorphic effect on immature stages of insect. o Juvenoids are larvicidal and ovicidal in action and they disrupt diapause and inhibit

embryogenesis in insects c) Anti JH or Precocenes

o They act by destroying corpora allata and preventing JH synthesis. Eg. EMD, FMev, and PB (Piperonyl Butoxide)

d) Chitin Synthesis inhibitors o Benzoyl phenyl ureas - have the ability of inhibiting chitin synthesis in vivo by

blocking the activity of the enzyme chitin synthetase o Two important compounds in this category are Diflubenzuron (Dimilin) and

Buprofezin The effects they produce on insects include- disruption of moulting, displacement of mandibles and labrum and ovicidal effect

❖ IGRS from Neem: azadirachtin from leaf and seed extracts of neem

8. ANTIFEEDANTS They inhibit feeding in insects when applied on the foliage (food) without impairing

their appetite and gustatory receptors or driving (repelling) them away from the food. The insect slowly dies due to starvation.

1. Groups of antifeedants i. Triazenes: Eg. AC 24055 inhibit feeding of caterpillars, cockroaches and beetles ii. Organotins- Triphenyl tin acetate against Colarado potato beetle and caterpillars iii.Carbamates- Baygon is a systemic antifeedants against cotton boll weevil iv.Botanicals

a) Pyrethrum: Extracted from flowers of Chrysanthemum cinerarifolium acts as antifeedants at low doses against biting fly, Glossina sp.

b) Neem: Extracted from leaves and fruits of neem (Azadirachta indica) is an antifeedant against many chewing pests and desert locust

c) Apple factor: Phlorizin is extracted from apple which is effective against non-apple feeding aphids


d) Solanum alkaloids: Leptine, tomatine and solanine are alkaloids extracted from Solanum plants and are antifeedants to leaf hoppers

11. BIOLOGICAL CONTROL

1. Parasitoids

o An insect parasite of an arthropod that is parasitic in its immature stage, killing the host in the process of development and adults are free living

o Most of the parasitoids belong to Hymenoptera (90%) and Diptera (10%)

Important families of insect parasitoids and examples

2. Agriculturally important predators

∗ A living organism throughout its life, kills its prey, and is usually larger than prey ∗ Requires more than one prey to complete its development

∗ 1898 - A coccinellid beetle, Cryptolaemus montrouzieri was imported into India from Australia and released against coffee green scale, Cocus viridis. Now it is effective against mealybugs in South India.

∗ 1920- Aphelinus mali introduced from England into India to control Woolly aphid on Apple, Eriosoma lanigerum

Family Example Target Category

1. Order : HYMENOPTERA

Trichogrammatidae

Trichogramma chilonis

Many lepidopterous pests

Egg parasitoid

Braconidae Bracon brevicornis, O. arenosella Larval parasitoid

Eulophidae Trichospilus pupivora

O. arenosella Pupal parasitoids

Tetrastichus israeli O. arenosella Pupal parasitoids

2) Order : DIPTERA

Tachinidae Sturmiopsis inferens Sugarcane shoot borer Chilo infuscatellus

Larval parasitoid

Spoggosia bezziana O. arenosella Larval parasitoid

Eucelatoria bryani H. armigera L a r v a l p u p a l parasitoid

3) Order : LEPIDOPTERA

Epiricanidae Epiricania melanoleuca

Sugarcane leafhopper, Pyrilla perpusilla

N y m p h a l a d u l t parasitoid


∗ 1929-31- Rodolia cardinalis imported into India (from USA) to control cottony cushion scale, Icerya purchasi on Wattle trees

Important insect predators against Agricultural pests with examples

3. Hyperparasitism Management of insect by use of microorganisms like viruses, bacteria, protozoa,

fungi, rickettsia and nematodes I. Viruses o Viruses coming under family Baculoviridae cause disease in lepidoptera larvae. Two

types of viruses are common. o NPV (Nucleopolyhedro virus) e.g. HaNPV (against Helicoverpa), SlNPV (against

Spodoptera litura) and marketed as Elcar o GV (Granulovirus)- e.g. CiGV o Mode of entry: The virus should be ingested to produce the disease. Due to alkaline gut

juice, the virions are liberated from the polyhedral coat which attack nuclei of cells of tissues viz., fat body tracheal matrix, haemocytes, sarcolemma of muscles, neurilemma and nerve cells of ganglion and brain.

II. Bacteria

Order Predator Prey insect

Coleoptera- Lady bird beetles

Coccinella septumpunctata Aphids

Cryptolaemus montrouzieri Papaya mealy bug, Cushiony Scales

C. transversalis Aphids

Cheilomenes sexmaculatus Aphids

Scymnus coccivora

Chilochorus nigritus Scales

Rodalia cardinalis Icerya purchasi

NeuropteraChrysoperla spp. All soft body insects, eggs of many

lepidopterans

Micromus igrotus Sugarcane wooly aphid

Lepidoptera Dipha aphidivora Sugarcane wooly aphid

HemipteraCyrtorhinus lividipennis Rice hoppers

Platymeris laevicollis Coconut rhinoceros beetle

Eucantheconidia furcellata Red hairy caterpillar

Predatory Spider Lycosa pseudoannulata Rice BPH

Predatory Mite Phytoseiulus persimilis Red spider mite


Entomogenous bacteria

Spore formers Non-spore formers (eg) Serratia marcescens, Pseudomonas spp. Streptococcus spp. Obligate Facultative

(eg) Bacillus popillae Crystelliferous Non- crystelliferous (eg.) B. thuringiensis (eg.) B. cereus i. Spore forming (Facultative, Crystelliferous)

- They produce spores and also toxin (endotoxin). - The endotoxin paralyses gut when ingested e.g. Bacillus thuringiensis effective

against lepidopteran. - Commercial products - Delfin, Dipel, Thuricide. Eg. Bt var kurstaki against

lepidopterans ii. Spore-forming (Obligate)

- e.g. Bacillus popilliae attacking beetles, produce ‘milky disease’ - Commercial product - ‘Doom’ against ‘white grubs’

iii. Non-spore forming - e.g. Serratia entomophila on grubs o Mode of entry of bacteria: The bacteria should be ingested to produce the disease. Due

to alkaline gut juice, endospore release delta endo toxins which create pore on mid gut walls and brought the death of insect by altering the homeostasis

III. Fungi o Green muscardine fungus- Metarhizium anisopliae (marketed as Biomax) against

coconut rhinoceros beetle o White muscardine fungus - Beaveria bassiana against lepidopteran larvae o White halo fungus - Verticillium lecanii on coffee green scale. o Hirsutella thompsoni (Mycar) on Red spider mite

IV.Nematodes o Infective juveniles enter in to host insect and cause death of insect either alone or with

the help of symbiotic bacteria o Steinernema spp., Heterorhabtidis spp. on lepidopteran larvae o Romanomermis culicivorax against mosquitoes


BIOTECHNOLOGY IN INSECT PEST MANAGEMENT

Transgenic plants o Transgenic plants are plants which possess one or more additional genes o This is achieved by cloning additional genes into the plant genome by genetic

engineering techniques o Transgenic plants have been produced by addition of one or more following genes o Refuge strategy (20%) - Planting of Bt cotton with non Bt cotton is followed in Bt

cotton cultivation to maintain susceptible population of target insect pest o Eg. Bollguard I against H. armigera in cotton o In India, Only transgenic plant for commercial cultivation is Bt cotton (from 2002

onwards). World’s largest cultivating transgenic plant - Soybeans (Herbicide resistance)

o In India - Genetic Engineering Approval Committee (GEAC) - authority for approving GM crops.

a. Bt endotoxin gene: The gram positive bacteria Bacillus thuringiensis produces a crystal toxin called δ (delta) endotoxin a stomach poison, kills the lepidopteran insects if consumed.

Transgenic Bt plants Target insect pests 1. Cotton Bollworms, S. litura 2. Maize European corn borer 3. Rice Leaf folder, stem borer 4. Tobacco, Tomato Cut worms 5. Potato, Egg plant Colarado potato beetle

b. Protease inhibitors (PI) gene ▪ Insects have proteases in their gut which are enzymes helping in digestion of protein.

Protease inhibitors are substances inhibit the proteases and affect digestion in insects. ▪ e.g. Cowpea trypsin inhibitor (CpTI) is a PI isolated from cowpea and cloned into

tobacco which is resistant to Heliothis virescens

c. α-Amylase inhibitor gene ▪ α-Amylase is a digestive enzyme present in insects for digestion of carbohydrate ▪ Transgenic tobacco and tomato expressing α-amylase inhibitor have been produced

which are resistant to Lepidopteran pests d. Lectins genes ▪ Lectins are proteins that bind to carbohydrates. When insect feed on lectins, it binds

to chitin in peritrophic membrane of midgut and prevents uptake of nutrients. ▪ e.g. Transgenic tobacco containing pea lectin gene is resistant to H. virescens


e. Enzyme genes ▪ Chitinase enzyme gene, and cholesterol oxidase gene have been cloned into plants and

these show insecticidal properties

Pyramiding of genes ▪ Engineering transgenic crops with more than one gene to get multi-mechanistic

resistance

PESTICIDES Chemical control: Management of insect pests using chemical pesticides

Pesticides: Chemicals which are used to kill pests; Insecticides – used to kill insects • In 1939, insecticidal property of DDT was discovered by Paul Muller of Switzerland

and was awarded Nobel Prize in 1948

Generations of insecticides

• Pesticide should be applied only based on the need, i.e. if pest reaches ETL. • Only 1% of the pesticide applied to crop reaches the target

I. PESTICIDES GROUPS Groups of pesticide: The pesticides are classified into various groups based on pest organism against which the compounds are used, their chemical nature, mode of entry and mode of action

Based on mode of entry a) Stomach poison: The insecticide applied in the leaves and other parts of the plant

when ingested, act in the digestive system of the insect and bring about kill (eg.) Malathion.

b) Contact Poison: The toxicant brings about death of the pest by means of contact (eg.) Fenvalerate.

c) Fumigant: Toxicant enters in vapour form into the tracheal system through spiracles (eg.) Aluminium phosphide

d) Systemic poison: Chemicals when applied to plant or soil are absorbed by foliage (or) roots and translocated throughout the plant and cause death of insect feeding on plant. (eg.) Dimethoate

Based on mode of action a) Physical poison: killing of insect by the physical effect of the toxicant (eg.) Activated

clay

Generation Year Compounds

I 1939-1942 BHC and DDT

II 1944-1947 Organophosphates and Carbamate

III 1967 Hormonal insecticides, JH mimic insect growth regulators

IV 1970s Synthetic pyrethroids


b) Protoplasmic poison: Toxicant responsible for precipitation of protein (eg.) Arsenicals c) Respiratory poison: Chemicals which inactivate respiratory enzymes (eg.) hydrogen

cyanide d) Nerve poison: Chemicals inhibit impulse conduction (axonic & synaptic) (eg.)

Malathion e) Chitin inhibition: Chemicals inhibit chitin synthesis (eg.) Diflubenzuron

Based on chemical nature A. Inorganic ompounds

Compounds of mineral origin (eg.) Sulphur, Zinc phosphide, Arsenic and Fluorine compounds

B. Synthetic organic a) Chlorinated hydrocarbon (OC): Compounds containing chlorine bonded to carbon

atoms (eg.) DDT, HCH, aldrin, endosulfan b) Organophosphorus (OP) compounds: Esters of phosphonic, phosphoric,

thiophosphoric (or) dithiophosphoric acid. (eg.) Malthion, fenthion, quinolphos. c) Carbamates: Esters of carbamic acid. (eg.) Carbaryl, carbofuran, aldicarb. d) Synthetic pyrethroids: Synthetic analogues of natural pyrethrins synthesized from

petroleum based chemicals (eg.) Fenvalerate, cypermethrin, permethrin

C. Newer insecticide molecules a) Neonicotinoids: Analogues of natural nicotinoids- (eg.) Imidacloprid, Acatamiprid b) Phenyl pyrazoles: (eg.) Fipronil c) Spinosyns (Spinosad): Fermented metabolite of soil actinomycete, Saccharopolyspora

spinosa d) Oxadiazone compounds: Indoxacarb e) Antibiotics: (eg). Avermectin (from Streptomyces avermitilis) and Emamectin benzoate f) Tetronic acid derivatives: (eg). Spiromecifen, Spirodiclofen g) Pthalicacid diamide: (eg). Flubendiamide

II. PESTICIDE FORMULATIONS Pure active ingredient (toxicant) is highly toxic and quantity available for application is low and hence they are diluted with many adjuvants. Types of formulation (mode of application).

A. For dry application Solid directly from container 1. Dusts (D)

• Active ingredient + a carrier such as clay (attapulgite, Kaolin, ash), organic flour (wood bark), pulverized minerals (sulphur, talc, lime, gypsum)

• Drift problem is more- highly toxic to beneficial insects 2. Granules (G)

• Liquid insecticides are coated over coarse particle of porous material like clay and corn cobs and they are much safer than dusts.


B. For spraying after mixing with water 1. Wettable powders (WP) • Active ingredient + inert dust + surfactant • When mixes with water and forms temporary suspension • Frequent agitation is needed to keep the insecticides in suspension • They are less phytotoxic than ECs and should never be used without dilution.

2. Emulsifiable concentrates (EC) • Toxicant + solvent + emulsifier + stabilizing agent • Emulsifier makes the water insoluble toxicant to water soluble and its yield a stable

milky solution when diluted with water • When applied, the solvent and water evaporate quickly leaving the toxicant alone.

3. Soluble powders (SP) • Consist of finely ground solid material which dissolve in water forming true solution.

4. Flowable (F) • Active ingredient is wet milled with a clay diluent and water • Constant agitation is needed to prevent formation of insecticide suspension and

settling.

5. Ultra low volume concentrates (ULV) • Special kind of high concentrate solutions and are applied without dilution with

special aerial or ground equipment to produce extremely fine spray

IV. SPECIAL PESTICIDE APPLICATION METHODS

Pralinage • The surface of banana sucker intended for planting is trimmed and dipped in wet clay

slurry followed by sprinkling of carbofuran 3G (40g/sucker) against burrowing nematode

Sett treatment • Treat the sugarcane setts in 0.05% malathion for 15 minutes to protect them from

scales • Treat the sugarcane setts in 0.05% Imidacloprid 70 WS 175 g/ ha or 7 g/l dipped for

16 minutes to protect them from termites

Trunk/stem injection • Injection of 5 ml of monocrotophos 36 WSC into the coconut stem against red palm

weevil and eriophyid mite • Pseudo stem injection of banana, an injecting gun or hypodermic syringe is used for

the control of banana aphid, vector of bunchy top disease •

Padding • 5-10ml of Monocrotophos 36WSP- against Stem borers of mango, silkcotton and

cashew


Swabbing • Coffee white borer is controlled by swabbing the trunk and branches with HCH

(BHC) 1 per cent suspension.

Root feeding • Trunk injection in coconut results in wounding of trees and root feeding is an alternate

and safe chemical method to control black headed caterpillar, eriophyid mite, red palm weevil

• Monocrotophos 10 ml and equal quantity of water are taken in a polythene bag and tied with root

Soil drenching • Chemical+water= solution is used for soil drenching to control certain subterranean

pests • (eg.) BHC 50 WP is mixed with water @ 1 kg in 65 litres of water and drench the soil

for the control of cotton/stem weevil and brinjal ash weevil grubs.

Capsule placement (eg.) In banana to control bunchy top vector (aphid) the insecticide is filled in gelatin

capsules and placed in the crown region

Fumigation: Solid and liquid Fumigants are used/ applied in a) Soil: To control the nematode in soil, the liquid fumigants are injected using injecting gun b) Storage: Liquid fumigants like Ethylene dibromide (EDB), carbon tetrachloride etc. and solid fumigants (Aluminium phosphide) are used in godowns to manage stored product pest c) Trunk: Aluminium phosphide ½ to 1 tablet is inserted into the affected portion of coconut tree and plugged with cement or mud against red palm weevil

V. PEST RESURGENCE • Tremendous increase in target pest population brought about by indiscriminate use of

insecticides • e.g. Quinalphos, phorate -Cause resurgence of BPH in rice and Carbofuran - Leaf

folder in rice • Simple resistance: Insect develops resistance only against the insecticide to which it

is exposed • Cross resistance: Insect develops resistance not only to exposed insecticide but also

to other related insecticides to which it is not already exposed

VI. SECONDARY PEST OUTBREAK • Application of a pesticide against a major pest, kills the natural enemies of minor or

secondary pest, causes their secondary outbreak e.g. Use of synthetic pyrethroids against bollworms in cotton killed natural enemies of whitefly causing an outbreak of whitefly


IMPORTANT STORAGE PESTS AND THEIR MANAGEMENT

I. PRIMARY FEEDERS a. Internal Feeders (feed entirely with in the grains) 1. Rice Weevil, Sitophilus oryzae (Coleoptera: Curculionidae)

Hosts: Rice (main), maize and other cereals in storage Damage: The developing larva lives and feeds inside the grain

2. Lesser Grain Borer, Rhizopertha dominica (Coleoptera.: Bostrychidae) Hosts: Stored cereals (main), cassava, cereal products, flours Damage: Both larvae and adults feed on the grains. The adults are quite long-lived

3. Pulse beetles, Callosobruchus chinensis and C. maculatus (Coleoptera: Bruchidae) Hosts: Cowpea, Soybean, and other pulses; Eggs are highly visible and laid on the seeds

4. Cigarette Beetle, Lasioderma serricorne (Coleoptera.: Anobiidae) Hosts: Stored leaf and cigarettes of tobacco, groundnut, peas and beans, many stored grains

5. Drug store beetle, Stegobium paniceum (Coleoptera: Anobiidae)- An external feeder Grubs make cylindrical g alleries on dried herbs and spices by making and adults feed little

6. Tamarind beetle, Pachymeres gonagra (Coleoptera: Bruchidae) Hosts: Groundnut (main) and other legumes (alternative). Damage: Larvae bore into the kernels, and a single larva makes a large hole in the cotyledons

7. Angoumois Grain Moth, Sitotroga cerealella (Lepidoptera: Gelechiidae) Hosts: Paddy, maize and wheat, Sorghum and other stored grains, and dried fruits

8. Potato Tuber Moth, Phthorimaea operculella (Lepidoptera: Gelechiidae) Hosts: Potato, tobacco, tomato, eggplant Damage: Tubers are bored by the caterpillars and they become infected with fungi or bacteria

9. Sweet Potato Weevil, Cylas formicarius (Curculionidae: Apionidae)

b. External Feeders (feed the grains from outside) 1. Khapra Beetle, Trogoderma granarium (Coleoptera: Dermestidae)- A

Hosts: Cereals and groundnut, Pulses, spices, and various cereal and pulse cakes 2. Red Flour Beetle, Tribolium castaneum (Coleoptera: Tenebrionidae)

Hosts: Maize, wheat and other stored grains 3. Almond moth, Ephestia cautella (Lepidoptera: Phycitiae)

Hosts: Maize, wheat, and other grains in store, Dried fruit, beans, nuts, bananas Damage: Webbing on the grain and on the surface of bags and feed the grains

4. Indian Meal Moth Plodia interpunctella (Lepidoptera: Phycitiae) Hosts: Meals and flours and Dried fruits Damage: The direct eating and contamination of foodstuffs with larvae, frass and silk webbing.

5. Rice moth Corcyra cephalonica (Staint), (Lepidoptera: Galleriidae) Larva webs the food grains with frass, moults and dense webbing.


II. SECONDARY FEEDERS (feed on broken grains which are out of condition) 1. Saw-toothed Grain Beetle: Oryzaephilus surinamensis (Coleoptera: Silvanidae) 2. Flat grain beetle, Cryptolestes pusillus (Coleoptera: Cucujidae) 3. Grain mite: Acarus siro (Order: Astigmata)

These pests attacks the germ of seeds, which reduces germination and spreads fungi

INTEGRATED MANAGEMENT OF STORAGE INSECTS 1. Preventive measures:

• Disinfection of stores and Legal methods 2. Curative measures I. Non-chemical control measures

• Heat treatment, Controlled atmosphere – using CO2 , Use of plant products, Use of activated clay, Irradiation, Airtight storage, Drying of grains

II. Chemical control measures a. Prophylactic treatment

• Application of Malathion 50 EC (or) DDVP 76% SC over the bags • Empty gunny bag soaking with 0.1% Malathion emulsion for 10 minutes and dried

before using for seed storage • Fumigants: EDCT and EDB

b. Curative treatment: Use of Aluminium phosphide (Period of fumigation is about 5 days)

• Cover fumigation- 3 tablets of 3 grams each per tonne of grain • Shed fumigation- 21 tablets of 3 grams each for 28 cu. metres

INSECT VECTORS OF PLANT DISEASES

List of some insect vectors of plant viral diseases

S. No Vector Diseases

I. Aphid (Aphididae) transmitted viruses

1. Myzus persicae Potato virus X, Potato leaf roll, Sugar beet yellow mosaic

2. Acyrthosiphon pisum Bean common mosaic, Bean yellow mosaic, Soybean mosaic, Pea enation mosaic

3. Toxoptera citricidus, T. aurantii Citrus tristeza virus

4. Aphis craccivora Cowpea mosaic, Groundnut rosette, Papaya mosaic

5. Aphis gossiphi, Myzus persicae Cucumber mosaic

6. Pentalonia nigronervosa var. typica

Banana bunchy top, Banana mosaic

7. P. nigronervosa var. caladii Katte and Foorkey diseases of cardamom

8. Rhopalosiphum maidis Maize streak mosaic virus, Sugarcane mosaic


List of some insect vectors of other plant diseases

II. Green Leaf hopper (Cicadellidae) transmitted viruses

1. Nephotettix virescens Rice tungro, rice grassy stunt

III. Zig Zag leaf (Cicadellidae) hopper transmitted virus

1. Recilia dorsalis Rice dwarf virus, Rice orange dwarf

IV. Leaf hopper (Cicadellidae) transmitted viruses

1. Cicadulin nubila Ragi mosaic

V. Plant hopper (Delphacidae) transmitted viruses

1. Peregrinus maidis Freckled yellows of sorghum, Maize mosaic

2. Nilaparvata lugens Rice ragged stunt, Orange stunt

VI. Whitefly (Aleyrodidae) transmitted viruses

1. Bamisia tabaci Bhendi yellow vein mosaic, Bhendi leaf curl, Chilli mosaic, Cotton mosaic, Tomato spotted wilt, Tobacco leaf curl

VII. Thrips (Thripidae) transmitted viruses

1. Thrips tabaci Papaya leaf curl, Tomato spotted wilt

2. Frankliniella schultzei Soybean spotted wilt, Groundnut bud necrosis

3. Scirtothrips dorsalis Chilli leaf curl

VIII. Mealy bugs (Pseudococcidae) transmitted viruses

1. Dysmicoccus brevipes Pine apple wilt

2. Saccharicoccus sacchari Sugarcane mottling

IX. Psyllid (Psyllidae) transmitted viruses

1. Diaphorina citri Citrus greening

S. No.

Vector Causative agent Disease

I. Leah hopper (Cicadellidae) transmitted diseases

1. Orosius albicinctus Phytoplasma Sesamum phyllody

2. Nephotettix virescens Phytoplasma Rice yellow dwarf

3. C e s t i u s ( H i s i m o n a s ) phycitis

Phytoplasma Little leaf of brinjal

II. Lacewing bug (Tingid bug- Tingidae) transmitted viruses


List of some mite (Eriophyidae) vectors of plant viral diseases

1. Nematode transmitting plant viruses a. NEPO viruses: These are nematode transmitted viruses with polyhedral particles.

Eg. Nematodes like, Xiphenema and Longidorus spp. b. NETU viruses: These are nematode transmitted viruses with tubular particles.

Eg. NETU viruses are transmitted by Trichodorus and Paratrichodorous.

List of important Nematode transmitted plant viruses

4. S t e p h a n i t e s typicus

Phytoplasma Coconut root wilt

Bees transmitted fungal diseases

1. Bees Claviceps purpureum and C. penisetti

Sugary disease of sorghum

Sl. No. Vector Disease

1. Aceria cajani Redgram sterility mosaic

2. A. mangiferae Mango malformation

3. A. tulipae Wheat streak mosaic

4. A. sacchari Sugarcane streak mosaic

S. No Nematode vector Virus Virus group

1. Paratrichodorus sp. & Trichodorus sp

Pea early browning, Tobacco rattle

NETU virus

2. Xiphenema index Grapevine fan leaf NEPO virus

3. Xiphenema americanum Tobacco and Tomato Ring spot NEPO virus


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