Entomology – agriinfo.in https://agriinfo.in Sun, 14 Apr 2019 13:11:12 +0000 en-US hourly 1 https://wordpress.org/?v=5.1.1 Practical significance of Biocontrol (Advantages) https://agriinfo.in/practical-significance-of-biocontrol-advantages-738/ https://agriinfo.in/practical-significance-of-biocontrol-advantages-738/#respond Fri, 18 May 2018 22:22:07 +0000 http://agriinfo.in/index.php/2018/05/18/practical-significance-of-biocontrol-advantages/ Practical significance of Biocontrol (Advantages) 1. It is exercised in a wide area. 2. The application of biotic agent is easy and possible in inaccessible areas like dense forest. 3. It is safe for humans and animal health. 4. The biotic agents survive in nature till the pest is prevalent. 5. It is a cheaper […]

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Practical significance of Biocontrol (Advantages)

1. It is exercised in a wide area.

2. The application of biotic agent is easy and possible in inaccessible areas like dense forest.

3. It is safe for humans and animal health.

4. The biotic agents survive in nature till the pest is prevalent.

5. It is a cheaper method if successfully deployed and persuaded.

6. It is a self perpetuating in nature.

7. It has no risk of environment pollution.

8. It does not require and special equipment to apply and can be mass multiplied at farmer’s level.

9. It may provide/generate employment revenues to rural people.

10. No problem of pest resistance and resurgence.

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Antidotes in Case of Pesticide Poisoning https://agriinfo.in/antidotes-in-case-of-pesticide-poisoning-1490/ https://agriinfo.in/antidotes-in-case-of-pesticide-poisoning-1490/#respond Fri, 18 May 2018 21:31:54 +0000 http://agriinfo.in/index.php/2018/05/18/antidotes-in-case-of-pesticide-poisoning/ Antidotes in Case of Pesticide Poisoning A. General Antidotes: 1. Removal of Poison: Remove poisons by including vomiting. 2. The “Universal Antidote”: A mixture of 7 g of activated charcoal, 3.5 g of magnesium oxide and 3.5 g of tannic acid in half a glass of warm water may be used to absorb or neutralize […]

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Antidotes in Case of Pesticide Poisoning

A. General Antidotes:

1. Removal of Poison: Remove poisons by including vomiting.

2. The “Universal Antidote”: A mixture of 7 g of activated charcoal, 3.5 g of magnesium oxide and 3.5 g of tannic acid in half a glass of warm water may be used to absorb or neutralize poisons. This mixture is useful in poisoning by acids, liquid glycosides and heavy metals. Except in cases of poisoning by corrosive substances it should be followed by gastric lavage.

3. Gastric Lavage (Removal of Stomach Contents): Lavage is the most important method for removing poisons from the stomach.

4. Demulcents (Substances having Soothing Effect): After the stomach has been emptied as completely as possible, give one of the following:
i. Raw egg white mixed with water.
ii. Gelatine 9 to 18 g dissolved in 570 ml of warm water.
iii. Butter
iv. Cream
v. Milk
vi. Mashed Potato
vii. Flour and water

B. Specific Antidotes for Some Pesticides:

The following emergency treatments are prescribed for poisoning by some specific pesticides.

a) BHC, Chlordane, DDT, Toxaphene, Methoxychlor and other Organochlorines:

If swallowed, give 28 g of magnesium sulphate (Epsom salts) in a glass of water, followed by hot tea or coffee. Inject 10 ml of 10% calcium gluconate intravenously. It necessary, inject Phenobarbital 0.1 g intravenously. Feed the patient with rich carbohydrate and calcium diet to prevent liver damage.

b) Organophosphorus Compounds (Parathion, HETP, and TEPP etc):

If the patient has blurred vision, abdominal cramps and tightness in the chest, give two tablets of atropine (each 1/100 g). Administer artificial respiration in case of respiratory failure. Do not give morphine.

c) Zinc Phosphide:

If the patient has taken the poison within 24 hours, proceed as follows: (1) Stir one teaspoonful of mustard powder into a glass of warm water and make the patient drink it: (2) After vomiting from treatment (1) has stopped, give the patient 5 g of potassium permanganate dissolved in a glass of water: (3) Ten minutes after the above treatment (2) have the patient drink a solution made of ½ teaspoonful of copper sulphate in a glass of water; and (4) Fifteen minutes after treatment (3) give the patient a solution made by dissolving one tablespoonful of magnesium sulphate (Epsomsalts) in a glass of water. If the poison has been taken earlier than 24 hours, omit treatment (1) above and give the others in order.

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Taxonomical Relationship of Insect Predators https://agriinfo.in/taxonomical-relationship-of-insect-predators-767/ https://agriinfo.in/taxonomical-relationship-of-insect-predators-767/#respond Wed, 16 May 2018 13:24:40 +0000 http://agriinfo.in/index.php/2018/05/16/taxonomical-relationship-of-insect-predators/ Taxonomical Relationship of Insect Predators Sweetman (1936) recorded about 14 Orders with 167 Families for predatory insect representatives. He further added in 1950, 2 more orders and some 42 families. The orders Coleoptera, Neuroptera, Hymenoptera, Diptera and Hemiptera contain families that so far have been of major importance in biological insect pest suppression. Greatest numbers […]

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Taxonomical Relationship of Insect Predators

Sweetman (1936) recorded about 14 Orders with 167 Families for predatory insect representatives. He further added in 1950, 2 more orders and some 42 families. The orders Coleoptera, Neuroptera, Hymenoptera, Diptera and Hemiptera contain families that so far have been of major importance in biological insect pest suppression. Greatest numbers of predatory species occur in order Coleoptera. The order Onodata is exclusively predaceous.

Taxonomic Characteristics of Important Predatory Insects:

1) Predaceous Coccinellids:

The lady bird beetles (Coleoptera; Coccinelidae).
a) The adult beetles have bright body in various shades of red, brown, tan or even black.
b) Usually they are spotted.
c) They range from 2-6 mm in length and are hemispherical in shape.
d) The head is small with chewing type of mouth parts.
e) The antennae are short and elevate.
f) Tarsi 3 segmented.
g) Larvae usually elongate with gradually tapering bodies. The body regions are distinct and colored with blue, black or orange. They appear warty of spiny dorsally.

2) Carabids:

The ground beetles (Coleoptera: Carabidae)
a) The beetles through predominantly black have some brilliantly colored in metallic greens, blues or purple.
b) Most species have broad elytra, narrow pronotum and a still narrower head.
c) They range from 2-25 mm in length.
d) The legs are long allowing for rapid movement.
e) The antennae are attacked between eyes and mandibles on each side of head.
f) The larvae are slightly flattened and slender tapering towards the posterior end which bears two spine like processes. They have chewing type of mouth parts.

3) Crysopids:

The green lace wings (Neuroptera: Chrysopidae)
a) These are slender bodied insects. Colored in a delicate green with golden eyes.
b) Antennae are long and slender.
c) Forewings are almost equal in size with green veins which fork profusely near wing margins.
d) The adults of some species and all of the larvae are predacious.
e) The spindle shaped larvae called”aphid-lionshave powerful sickle shaped mandibles. The legs are slender and hairy and body is provided with a row of spine bearing tubercles along each side Aphid-lions are usually mottled with grey, yellow, green red or black.

4) Formicids:

 The ants (Hymenoptera: Formicidae)
a) These are social insects. Many displaying polymorphism.
b) They have chewing type of mouth parts.
c) The antennae are strongly elbowed with a very long first segment.
d) Body segments are distinct and thorax is slenderest region. The gaster or swollen part of the abdomen is attached to the thorax with a short slender petiole bearing one or two projectious.

5) Syrphids:

The entomophagous syrphid flies (Diptera, Syrphidae)
a) They are predators only in their larval stages.
b) Adults are diverse in form, some slender and some broad and their bodies are polished black or metallic blue or green with prominent yellow bands, spots or hairs.
c) They are 3 to 25 mm long and are separable from others Dipters by the presence of spurious wing vein between radius 4+5 and media 1+2.
d) The green or tan larvae are elongate, legless maggots with pointed sucking mandibles.

6) Mirids:

The plants bugs (Hemiptera: Miridae)
a) The plant bugs contain many predaceous species.
b) Adults are 2.5 to 6 mm long, velvety in appearance and often highly colored. They have cureus and 1-2 large cells in the membrane of fore wings, both rostrum and antennae 4 segmented and no ocelli.
c) The body is elongate oval and often clothed with fine hairs. The hemelytra are longer than abdomen and prevailing colors are combinations of green, black or red with spots or stripes of black, yellow, white or red.
d) Mirids have sucking type of mouth parts.
e) Metamorphosis is incomplete and nymph is predaceous.

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Order: Coleoptera https://agriinfo.in/order-coleoptera-1540/ https://agriinfo.in/order-coleoptera-1540/#respond Sat, 12 May 2018 03:00:18 +0000 http://agriinfo.in/index.php/2018/05/12/order-coleoptera/ Order: Coleoptera (Coleos = sheeth & pteron = wing) E.g. Beetles and Weevils Economic Importance: Some insects are predators or scavengers; many are crop pests while some are destructive to stored grains. Characters: 1. Minute large insects. 2. Fore wings modified into horny or leathery elytra which meet to form a mid-dorsal line, fore wings […]

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Order: Coleoptera

(Coleos = sheeth & pteron = wing)
E.g. Beetles and Weevils

Economic Importance:

Some insects are predators or scavengers; many are crop pests while some are destructive to stored grains.

Characters:

1. Minute large insects.
2. Fore wings modified into horny or leathery elytra which meet to form a mid-dorsal line, fore wings not used in flight.
3. Hind wings membranous, folded beneath the elytra or often reduced or wanting.
4. Mouth parts mandibulate.
5. Prothorax large and mobile, mesothorax reduced.
6. Abdominal tergiles often sclerotized.
7. Larvae campodaidorm or crucidorm, seldom apodous with mandibulate mouth part.
8. Pupal adecticous and exarate, rarely obtect.
9. Metamorphosis complete.

The order is divided into four sub-orders viz.

Archostemata, Myxophaga, Adephaga and Polyphaga Larvae of the insect belonging to sub-order Archostemata are wood feeders while the insect from sub-order Myxophaga are found in wet places by streams Comparative characters of the later two sub-orders are as follows:-

S.O. Adephaga

  1. Notopleural sulcus distinctly present in Prothorax.
  2. Wings usually with (2 cm cu –cross veins defining) an oblongum.
  3. Testes tubular and ovariole polytropic.
  4. Larvae with 6 segments in legs.

S.O. Polyphaga

  1. Notopleural sulcus never distinct in Prothorax.
  2. Wings have no oblongum.
  3. Testes follicular and ovariole acrotrophic.
  4. Larvae with 5 or fewer segments in legs, ending with single claw.

 

Important Families:

i. Cicindelidae e.g. Tiger beetle

ii. Dytiscidae e.g. Water beetle

iii. Carabidae e.g. Ground beetle

Sub-order: Polyphaga

1) Notopleural sulcus never distinct in Prothorax

Important Families:

i. Meloidae e.g. Blister beetle
ii. Coccinellidae e.g. Lady bird beetle, Epilachna beetle
iii. Scarabaeidae e.g. White grub
iv. Cerambycidae e.g. Mango stem borer, Grape stem girdler
v. Chrysomelidae e.g. Rice hispa
vi. Bruchidae   e.g. Pulse beetle
vii. Tenebrionidae e.g. Rust red flour beetle
viii. Dermestidae e.g. Carpel beetle, Khapra beetle
ix. Cucujidae   e.g. Saw toothed grain beetle
x. Bostrychidae e.g. Lesser grain borer
xi.Melolonthidae e.g. Cockchafer beetle
xii.Dynastidae e.g. Rhinoceros beetle
xiii. Curculionidae e.g. Weevils

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Instruction for Dissection of Honey Bees, Red Cotton Bug and House Fly https://agriinfo.in/instruction-for-dissection-of-honey-bees-red-cotton-bug-and-house-fly-1512/ https://agriinfo.in/instruction-for-dissection-of-honey-bees-red-cotton-bug-and-house-fly-1512/#respond Wed, 09 May 2018 02:03:23 +0000 http://agriinfo.in/index.php/2018/05/09/instruction-for-dissection-of-honey-bees-red-cotton-bug-and-house-fly/ Instruction for Dissection of Honey Bees, Red Cotton Bug and House Fly Instruction for Dissection of Honey Bees: Cut the head from the thorax, Hold the head between the thumb and the index finger with the mouthparts facing you. Remove each mandible by exerting outward pressure at the base with a needle. Change the position […]

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Instruction for Dissection of Honey Bees, Red Cotton Bug and House Fly

Instruction for Dissection of Honey Bees:

Cut the head from the thorax, Hold the head between the thumb and the index finger with the mouthparts facing you. Remove each mandible by exerting outward pressure at the base with a needle. Change the position the head, so that its posterior side faces you in an inverted position. Make it flaccid by applying some pressure. Remove the maxilla-labial complex by exerting upward pressure at its base with a needle. Mount the mouthparts in glycerin on a slide and remove the extraneous tissues from them. Place a cover-slip over them and examine under a microscope.

Instruction for Dissection of Red Cotton Bug:

Cut the head from the thorax. Hold the head between the thumb and the index-finger and make it flaccid by applying some pressure. Place it on a microscope slide and moisten the proboscis with a drop of water. Press the proboscis gently at various places with the help of a needle till the stylets come out of the labial sheath and get disengaged. Mount the mouthparts in glycerin on a microscope slide and arrange them as shown in the diagram. Place a cover them and examine under a microscope.

Instructions for Dissection of House Fly:

Cut the head from the thorax. Hold the head between the thumb and the index finger with the posterior side of the proboscis facing you in an inverted position. Remove the proboscis by exerting upward pressure at its base with a needle. Place the proboscis in glycerin on a microscope slide and remove the extraneous tissues from it. Place a cover slip over it and examine under a microscope.

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Desirable Attributes of Bio-agents https://agriinfo.in/desirable-attributes-of-bio-agents-770/ https://agriinfo.in/desirable-attributes-of-bio-agents-770/#respond Wed, 09 May 2018 01:28:20 +0000 http://agriinfo.in/index.php/2018/05/09/desirable-attributes-of-bio-agents/ Desirable Attributes of Bio-agents The classical practice of introduction exotic beneficial organisms or pest suppression is the only useful method under restricted conditions. While introducing beneficial organisms, the concern of the desirable attributes of a natural enemies and a consideration of some basic ecological principal have bearing as success or failure of biological pest-suppression programmes. […]

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Desirable Attributes of Bio-agents

The classical practice of introduction exotic beneficial organisms or pest suppression is the only useful method under restricted conditions. While introducing beneficial organisms, the concern of the desirable attributes of a natural enemies and a consideration of some basic ecological principal have bearing as success or failure of biological pest-suppression programmes.

Desirable Attributes of Natural Enemies:

In order to search for efficient beneficial organisms for use in biological insect pest suppression it requires some idea beforehand that what we are seeking. Before introducing new natural enemies from exotic locations or analyzing those species which are already present for same way of augmenting their usefulness we must know their characteristics of species to display it an efficient regulatory relationship with the pest. Thus proper selection of natural enemies of insect is an important part of success of Biocontrol.

The Organisms should Possess Following Attributes:

1) Ecological Compatibility:

It is usually important to seek species whose ecological requirements are similar to those of the intended target insect. Parasitoids are frequently limited in effectiveness and have greater sensitivity to cold; desiccation, heat etc. and hence it is of great consideration for parasite species to withstand such condition suitable for the host. Disparity in ecological responses may be an important limiting factor in the effectiveness of native beneficial organisms and an environment manipulation of same sort may make them successful regulative agents e.g. high humidity by irrigation for development of pathogenic fungi against alfalfa aphids.

2) Temporal Synchronization:

The pest and its natural enemies should be in the same place at the same time and also their life cycles must be synchronized for adequate regulation to be possible. Thus the reproductive stage of a successful egg parasitoid must be active at the time of the hosts egg in every generation of the host. The efficacy of poorly synchronized organism may sometimes be improved. The practice of periodic inundative release of beneficial insects is another way of artificially synchronizing the occurrence of parasitoid and host e.g. release of Trichogramma spp.

3) Density Responsiveness:

The most desirable biological control agents should exhibit positive rapid density responsiveness. Proportion of natural enemy of pest should be maintained. Generally natural enemies have short life cycle, whereas pest has long life cycles. A strong functional response refers to within generation behavioral activity of the individual parasitoid or predator in increasing its attacks against increasingly numerous hosts or prey, on the other hand, numerical response refers largely to a multigenerational reproductive increase by the organism in response to increasing host density. A rapid and strong numerical response characteristic is the most important attributes of a successful agent of pest mortality.

4) Reproductive Potential:

One important factor in the display of density responsiveness is high reproductive capacity through either short generation time, high fecundity or both. In most cases, the parasitoid or predator is searched with an innate potential for increase greater than that of the host/prey.

5) Searching Capacity:

The ability to find host/prey at low density has significant bearing on the long term success of organism in the more stable situations. A beneficial organism which can successfully utilize low density population and reduce its number through efficient searching behavior is a desirable key regulative agent to be sought. A true ideal beneficial insect would possess both high reproductive potential and good searching capacity, but it case of successful biological control full utilization of former factor rarely comes into play because of low pest densities and efficient searching ability becomes the primary characteristic because it maintains those low densities.

6) Dispersal Capacity:

The ability of an introduced beneficial species to easily and rapidly expand its sphere of influence in space to coincide with that of the host is closely tied to its searching capacity and ecology adaptability. Most good biological control agents shop high dispersal capability, season ends the pest migrates and natural enemy should also ingrate.

7) Host Specificity and Compatibility:

A parasitoid or predator which is monophagous or silently Oligophagous indicates a high degree of biological adaptation to the host and probably a greater degree of direct degree of direct and rapid responsiveness to density changes in the population of the target host. Host specificity is closely ties with compatibility that is the degree of biological adaptation. Monophagous entomophagous have usually evolved a high degree of adaptation to the defensive mechanisms of their host/prey. Predator with polyphagous nature will do the purpose. Compatibility refers to combination of unnatural enemies. Likewise lady bird beetles should not eat Trichogramma spp.

8) Food Requirements and Habitats:

This attributes is another consideration in choosing a potentially useful beneficial organisms. For sustenance of natural enemy some sort of food should be available to natural enemy like pollen, Honey etc. and also shattering places. Nutritional requirement of natural enemies should get fulfilled. Habitat refers to sheltering places and they should be available for natural enemies.

9) Hyperparasitism:

This is a negative attribute to be avoided in selecting Biocontrol agents. To eliminate secondary parasitoids under certain situations Hyperparasitism is most important one.

10) Culturability:

This is an important attribute indicating ability of organism which can be mass reared under artificial condition for large scale release programmes. Hence the introduced species must be an enable to laboratory culture.

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Historical Developments in Biological Control – Early history to 1888 (Ancient period) https://agriinfo.in/historical-developments-in-biological-control-early-history-to-1888-ancient-period-741/ https://agriinfo.in/historical-developments-in-biological-control-early-history-to-1888-ancient-period-741/#respond Tue, 08 May 2018 03:41:45 +0000 http://agriinfo.in/index.php/2018/05/08/historical-developments-in-biological-control-early-history-to-1888-ancient-period/ Historical Developments in Biological Control – Early history to 1888 (Ancient period) The idea that the insects could be use intentionally to suppress the population of other insect is an ancient one. Charles Darwin recognized appearance of first insect primitive humans probably utilized insects as a part of their own field diet. It assumed that […]

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Historical Developments in Biological Control – Early history to 1888 (Ancient period)

The idea that the insects could be use intentionally to suppress the population of other insect is an ancient one. Charles Darwin recognized appearance of first insect primitive humans probably utilized insects as a part of their own field diet. It assumed that man himself recognized perdition at an early date by man himself. The discovery of agriculture and development during Neolithic time (about 1000 BC) put human kind into very direct competition with insect for food. Just as early as man observed birds eating insects, snake eating rodent, mice and rats eradicated by house cat by Egyptian.

“Historia Animalium” described the ravages the wax moth to honey comb. Later on Pliny (23-79 AD), a Roman author recognized several disease conditions in bees. Silkworm also suffers from various diseases and recognized as early as 1000 AD. The true biological suppression of insect pest in modern sense was practiced by Chinese citrus growers by introducing predaceous ants in to orchards to control citrus peat. In the old Chinese book ‘Wonder from Southern China’ (900 AD) refers that large yellow ants with long legs used to protect oranges from worms and ant’s nest was available for sale in village markets ‘Anton’ until 1939.

Ulysses Aldrovandis in his book “De Animalibus Insects” (1802) summarized all published literature on insects and included first published literature on insect parasitism. An attack of Gregarian parasitoid, Apanteles glomeratus of the cabbage butterfly was known. Francisco Redi (1860) described phenomenon of parasitism of aphid by an ichneumonids. Vallisnleri (1730) first noted unique association between parasitic wasps, A.glomerctus of cabbage butterfly. Rene Reanmur (1734) advanced the idea of biological insect suppression and suggested introducing the eggs of aphidivorous flies (lace wing) into green houses. A lady bird beetle, green lace using and wasp were also recommended for suppression of aphids. The first International Movement of predator was accompanied in 1762. The Indian ‘Mynali’ bird was introduced from India to Maurtius with a purpose of red locust control in sugarcane. Mitchill (1823) discussed various parasitic animals including hymenoptera form insects. Herrick (1840) discussed an egg and pupal parasitoid of hesion fly Asalitch (1845) proposed importation of parasitoids from England to America to control wheat midge. Agostina Bassi (1835), a pioneer insect pathologist first demonstrated the fungal nature of mustarding disease of the silk worm. Kirby and Spence (1867) recommended and used lady bird beetle for aphid control. They were also aware of usefulness of mantids, coccinlids, dragonflies, spiders etc.

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Rearing Techniques of Mulberry Silk Worm https://agriinfo.in/rearing-techniques-of-mulberry-silk-worm-1496/ https://agriinfo.in/rearing-techniques-of-mulberry-silk-worm-1496/#respond Mon, 07 May 2018 08:43:08 +0000 http://agriinfo.in/index.php/2018/05/07/rearing-techniques-of-mulberry-silk-worm/ Rearing Techniques of Mulberry Silk Worm The silkworm can be reared in places where the temperature ranges from 25 ̊ to 30 ̊ C and humidity from 70 to 80 percent. 1. The fertilized moth is covered with an inverted funnel and eggs are allowed to be laid over a cardboard. 2. The egg masses […]

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Rearing Techniques of Mulberry Silk Worm

The silkworm can be reared in places where the temperature ranges from 25 ̊ to 30 ̊ C and humidity from 70 to 80 percent.

1. The fertilized moth is covered with an inverted funnel and eggs are allowed to be laid over a cardboard.
2. The egg masses are brushed with a fine brush to remove any parasites and to obtain an uniform hatch.
3. In a bamboo tray paddy husk is spread and very tender chopped mulberry leaves are added to tray and the hatched out larvae are transferred to the leaves.
4. The leaves are changed every two or three hours during the first two or three days.
5. From fourth day, the caterpillars are given clean full leaves.
6. A net of small mesh is placed over the tray and the leaves are placed over this. The caterpillars crawl through the net to the fresh leaves. After one or two hours the net is taken and placed in another tray.
7. The unused leaves and the voids in the former trays are thrown out.
8. The feeding trays are cleaned at frequent intervals.
9. Full grown caterpillars are spread in a regular order about 8 cm apart in the Chandrika and are allowed to pupate.
10. The cocoon is constructed of a single reel able thread of silk. If the moths are allowed to emerge from the cocoons the silk thread is cut into pieces during the process. Therefore, the pupae are killed two or three days before the emergence of moths by exposing them to sun for two or three days, by passing steam or hot air over them or by fumigating with a chemical. This is known as stifling.
11. The stifled cocoons are dried and the loose outer floss is removed by brushing.
12. They are then soaked in warm water to soften the gum that binds the silk threads.
13. Threads from four to five cocoons are put in a spool of reeling machine and made to a single thread of sufficient thickness to form the raw silk. About 50 to 60 percent of the silk of the cocoon is reel able and it forms the raw silk and the rest is formed into waste silk.
14. Raw silk is boiled, steamed, stretched, purified by acid and washed twice or thrice to remove the gum and to bring out the characteristic and much cherish luster.
15. The cocoons required for further rearing are kept separately and moths are slowed to emerge from them.

The consumption of leaves by the caterpillars increases with their age from about 0.1 gram per day per caterpillar during the first stage to 5 gram during the last stage and the total consumption during the entire larval life of a caterpillar is about 90 grams.

A dry cocoon weighs of about the gram and is about two-third weight of a green cocoon. The chrysalides form 60 percent and the silk matter 40 percent of the weight of the cocoon. It has been estimated that about 60,000 cocoons yield a kilogram of raw silk and they require about a ton of mulberry leaves.

A good cocoon should be round, firm and silvery white in colour. It should have a comparatively large proportion of reel able silk and it should have been spun by a caterpillar, which does not consume very large quantities of leaves.

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Jowar Shoot Fly & Jowar Stem Borer – Pests of Jowar https://agriinfo.in/jowar-shoot-fly-jowar-stem-borer-pests-of-jowar-138/ https://agriinfo.in/jowar-shoot-fly-jowar-stem-borer-pests-of-jowar-138/#respond Sun, 22 Apr 2018 08:28:02 +0000 http://agriinfo.in/index.php/2018/03/03/jowar-shoot-fly-jowar-stem-borer-pests-of-jowar/ Jowar Shoot Fly & Jowar Stem Borer – Pests of Jowar A. Jowar Shoot Fly Scientific Name:  Atherigona soccata Rond. Class & Order: Anthomyidae – Diptera Economic Importance: It is one of the serious pests of sorghum in India. The Pest attacks the crop only in early stage of growth and infestation goes up to […]

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Jowar Shoot Fly & Jowar Stem Borer – Pests of Jowar

A. Jowar Shoot Fly

Scientific Name:  Atherigona soccata Rond.
Class & Order: Anthomyidae – Diptera

Economic Importance: It is one of the serious pests of sorghum in India. The Pest attacks the crop only in early stage of growth and infestation goes up to 80%. The high yielding hybrids are more susceptible to the attack of this fly. The total loss in yield is sometimes as high as 60%. The pest is very serious on kharif and Rabi crops in Maharashtra State.

Marks of Identification: Adult fly is dark grey, like the common house fly but much smaller in size, 6 & 4 dark spots on abdominal segments of female & male respectively (arranged in rows of two) Maggot are legless, tapering towards head, pale yellow, small ( 10- 12 mm in length ).

Host plants: Jowar and grasses like Andropogan sorghum, Cynodon dactylon and Panicum spp.

Life history: Eggs: Eggs are average 40 eggs are laid by a female singly on lower surface of leaves & tender stem. Incubation period is of 2-3 days. Larva: larval period 10 to 12 days. Four larval instars are present. Pupa: Pupation in stem. Pupal period is about a week. Adult longevity is 12-1 4 days. Life cycle completes in 2-3 weeks. Several generations in a year. Carry over -The pest over winters in adult stage on grasses.

Seasonal occurrence: The insect attacks the seedlings and late sown crops are attacked badly. The attack is severe during July to October. Cloudy weather favours multiplication of the insect. In rabi, early sown crop suffers more and hence sowing should be delayed possibly

Nature of Damage: Maggots on hatching from the eggs bore into the central shoots of seedlings and kill the growing point, producing "dead hearts". They feed on the decaying core of the shoots. Subsequently on death of central shoot, plant gives out tillers and plant gets bushy appearance.
 
Management Practices:

  1. Sow the crop as early as possible i.e. immediately after the onset of rains or within 15 days after receiving of rains. Increase the seed rate to make up the loss.

  2. Use the seeds treated with carbofuran 50 SP @ 5% a.i. by wt. of seed (Gum Arabic as sticker) or carbosulfan 25 STD @ 200 gm / kg of seed OR 3% carbofuran granuals @ 5 kgs /50 kgs of seed by using slurry of wheat flour as sticker. OR Application of phorate 10 gm @ 10 Kg / ha in soil at sowing OR Spray the crop with 0.05% endosulfan soon as 10% seedlings are infested or 1 egg / 10seedlings are noticed.
  3. Removal and destruction of affected shoots along with the larvae.
  4. Use resistant (Maldandi 35-1) or less susceptible varieties like R.S. V.9 R (Swati), S.P. V86 for planting.

 

B. Jowar Stem Borer

Scientific Name: Chilo partellus S.
Class & Order: Pyralidae – Lepidoptera

Economic Importance: It is one of the major pests of Jowar and has a wide distribution. The infestation is noticed till harvest and the grown up plants when damaged loose their vigour and put forth week ears. The infestation is more pronounced on rabi and hot weather crops.

Marks of Identification: Moths – medium sized, straw coloured, yellowish grey forewings. The hind wings are whitish. Caterpillar – ditty white, brown head, many dark spots on the body, 12- 20 mm in length.

Host plants: Although principle hosts are Jowar and maize, it has also been recorded on Sugarcane, Ragi and certain grasses.

Life history: Eggs – about 300 eggs are laid, on leaves in clusters, incubation period about 6 days larval period:  3-4 weeks. Pupa: pupation in stem. Pupal period 7-10 days. Before pupation larva prepare a hole on stem at ground level for the moth to escape / come out. Adult longevity 2-4 days

Life cycle: completed in 6-7 weeks. About 4-5 generations are completed in a year.
 
Carry Over: The pest hibernates in the larval stage in stubbles. Seasonal occurrence: The pest is generally active from July to November. The infestation is more on rabi & summer crops.

Nature of damage: On hatching from the eggs, the larvae initially feed on tender leaf whorls causing series of holes in the leaf lamina and later bore into the stems, feed on the central shoots causing their death, commonly known as “dead hearts”
 
Management Practices: Preventive and curative measures.

Preventive:

  1. Collection and destruction of stubbles after the harvest of crop to kill hibernating larvae

  2. Increase the seed rate to compensate the loss.

  3. Follow proper crop rotation (with non host crop).

  4. Use of light traps.

Curative:

  1. Removal & destruction of affected shoots along with the larvae.

  2. Spraying with 0.05% endosulfan or 0.2%carbaryl OR whorl application of endosulfan 4G @ 10kg/ha, when 10% plants are infested.

 

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Important Terms used in Biological Control of Crop Pests – I https://agriinfo.in/important-terms-used-in-biological-control-of-crop-pests-i-746/ https://agriinfo.in/important-terms-used-in-biological-control-of-crop-pests-i-746/#respond Tue, 17 Apr 2018 17:41:56 +0000 http://agriinfo.in/index.php/2018/04/17/important-terms-used-in-biological-control-of-crop-pests-i/ Important Terms used in Biological Control of Crop Pests – I Accretive Release: A method of periodic introduction of biotic agents in which annual early season liberations against fairly abundant pest populations allow the beneficial organism population to increase naturally in response to rising pest densities as the season progresses. Agroccosystem: The modified and simplified […]

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Important Terms used in Biological Control of Crop Pests – I

Accretive Release:

A method of periodic introduction of biotic agents in which annual early season liberations against fairly abundant pest populations allow the beneficial organism population to increase naturally in response to rising pest densities as the season progresses.

Agroccosystem:

The modified and simplified system of plants, animals and habitat used for human agricultural purposes.

Antibiosis:

According to Painter (1951), it refers preventative, injurious or destructive effects on the insect life history which result from the insect’s use of a resistant host variety or species for food.

Antifeedant:

A natural synthetic chemical substance which acts either to inhibit the stimulation of gustatory receptors which normally recognize suitable food, or to stimulate receptors which elicit a negative response to deterrent chemicals.

Arrhenotoky:

A facultative type of parthogenetic reproductive in which only male progeny are produced.

Augmentation:

It is the process which involves to improve the effectiveness of natural enemies  by manipulating either mass production, periodic colonization or by genetic improvement.

Autodial Control:

The use of an insect species against itself, usually through, some means of genetic modification, to suppress or eradicate its natural population.

Autoparasitism:

A special type of hyper parasitism in which the female develops as primary parasitoid, but the male is a secondary parasitoid through females of its own species.

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