sericulture priject

7/22/2019 SERICULTURE PRIJECT

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SERICULTURE AT RSRS ,SASHASPUR

INTRODUCTION:

Silk, thequeen of textiles is a natural fibre which is secreted by scereted by certain

insect larvae known as silkworm. These silkworm are divided into two groups, i.e. mulberry

silkworms and non mulberry silkworms.Mulberry silkworm belongs to the family

'bombycidae' and non mulberry silkworms Eri silkworms, Muga silkworms, Tasar silkworms,

Oak Tasar silkworms belongs to the family 'Saturnidae' under the order

Lepidoptera.Mulberry silkworm has been domesticated while nonmulberry silkworm fibrous

covering known as cocoon.Silk is a lepidopteran in silkworm larvae.Silk is made up of fibrin(C30H46N10O16) fiber and sericin (C12H40N10O16) a gummy material which coat the

filament. The cocoon is reled out into fine silk thread often processing up to a lengthof

about 350 to 2000 meters.

Sericulture referred as silkworm rearing and harvesting of cocoons for production of silk.

Sericulture is devided from the word "Su (Si)" mening silk. Silk is traditionally associated the

socio economic life of any countries and it has been used for making exquisite textiles and

royal dresses since immemorial. For the first time, it was introduced in China by the Chinees

empress, Si Ling Si around 2640 B.C. The Shang Tung province in China is known to be the

original home of silk. By the 12th

century B.C., this fabulous silk spread to the other part of

the world. Initially silk used to come into India from China.

SERICULTURE STATUS IN INDIA:

World wide approx. 58 countries are engaged in silk production.India produce all five kinds of silk i.e.

mulberry, Eri, muga, tasar & oak tasar and ranked 2nd

after china in silk production.Present silk

production of india is approx. 16319 MT (16% of world) per annum while home need is

27700 MT. of the total silk production of india tropical trasar shared 315 MT per

annum.Indian silk industry is paying an inportant role in technology transfer, socio-economy

& employment generation, however it is the need of enhancing silk production & to

complete the global market. Silk industry is an agro based industry which most probably

depend on the quality breed, seed & feed. The breed refer to high hetrotic vigour, seed to

eggs and feed to the leaf, but the quality is acommon factor. The availability of quality leaf

of mulberry depend on the soil fertility where the mulberry plant grown.

Sericulture is an on-farm and non-farm agro-based cottage industry. it play a major

role in improving socio-economic status of tribal,weaker section, landless erning group.

Indiaenjoy all five kinds of silk, i.e. mulberry, muga, eri, tasar & oak-tasar and ranked second



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in silk production after China among 58 silk producing country in the world. The CSB (Govt.

of ) is the leading house of governing & guiding all the sericultural activities in India. The

work related are R&D, technol.dev. & transfer, developing experties, extension, adoption

rearer, trg., linkage network with NGO's, state & abroad. which automatically helpin

generation employment & improving socio-economic status.

SERICULTURE AND SILK TYPE:

Name of Silkworm Name of food plants

1) mulberry Silkworm Mulberry plants

Bombayx mori Morus alba

2) Eri Silkworm Arendi plant Caster ricinus

Attacus ricuni, Philosamia ricini

P. Cynthia

3) muga Silkworm Som & salu plants

Antheraea Assamensis Arjun & Asan plants

4) Tasar Silkworm Oak plants

Antheraea proylei, Antheraea roylei, Quercus serratye,Q. dealdbata,

Antheraea pernyi Q. incana, Q. himalayan

SILK PRODUCING STATES IN INDIA:

1. Mulberry sericulture is practiced mainly in J&K, West Bengal, Doon Vally, Manipur,

Assam, Punjab, Himachal Pradesh, Andhra Pradesh, South India and some parts of Uttar

Pradesh. The silkworm feeding on mulberry leaf, forms encasement around it, toprotect

itself at the time of metamorphosis. This encasement is known as a cocoon, which is the

commercially important product in sericulture. The mulberry sector can bedivided into two



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zones i.e, uni-voltine and bi\multi-voltine. There are two common mulberry tree speciesi.e

the native red mulbery (Morus rubra), and the Asian white mulberry(Morus alba). The

malberry only grown up to 65 feet, with rough, redddish-brown bark. The white mulberry

only growns up 40 feet tall, with rough, lighter, ochre-gray bark and spreading branches.

2) Eri sericulture is practiced in Assam, Manipur, Nagaland, West Bengal, Orissa, Bihar, M.P,

Meghalaya, Arunachal Pradesh and Jharkhand mostly. Eri silk worms may be of the species

of Philosamia ricini or P. Cynthia. The P. ricini is domesticated and is fed on castor leaves. Eri

cocoons are open ended cocoons utilized fpr spinning purposes only. The filament of the

cocoons is not continuous likes mulberry silk and also noteven of uniform in nature. The Eri

silk is white or brick red in colour.

3) Muga sericulture is practiced only in Bhrahmaputra valley Assam. However, anegligible

quantity of muga silk is produced in Arunachal Pradesh , Mizoram and Nagaland. The

Machilus bombycina (som) and Litasaea polyantha (soaiu). Secondary food plants also exit.

Muga silk is very attractive and golden in colour.

4) Tasar sericulture is practiced in West Bengal, Orissa, M.P., U.P., Bihar, Maharashtra,

Assam, Andhra Pradesh, Chhattisgarh and Jharkhand. Tasar silk is generated by the

silkworm, Antheraea mylitta which mainly thrive on the food plants Asan and Arjun. Tasar is

copperish colour, coarse silk mainly used for furnishings and interiors. It is less lustrous than

mulberry silk but has its own feel and appeal. the rearing are conducted in nature on the

trees in the open. Tasar culture is the main stay for many atribal community in India.

5) Oak Tasar sericulture is in the sub-himalayan belt of India covering the state of Manipur,

Himachal Pradesh, U.p, Assam, J&K and Meghalaya. it is a finer variety of Tasar generated by

the silkworm, Antheraea proyeli J. In India which feed on natural food plants on oak. China

is the major producer of oak in the world and this comes from another silkworm which is

known as Antheraea pernyi.

CLASSIFICATION OF SILKWORM:

Phylum - Arthopoda

Sub Phylum - Mandibulata

Class - Insecta

Sub Class - Pterygota

Order - Lepidoptera

Family - Bombycidae/ Saturnidae

Genus - bombyx, Antheraea, Attacus, Philosamia



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Species - Mori, Mylitta, Proylei, Assamensis, Ricini

SERICULTURE PRACTICES AND PACKAGES:

A) SILKWORM SEED PRODUCTION

B) SILKWORM REARING

C) SILKWORM DISEASES & PESTS

A) SILKWORM SEED PRODUCTION:

Production of quality silkworm seed is a vital step in successful sericulture.

Hybrida are commercial for production. For good quality hybrid eggs, a sound organisation

for multiplication of pure breeds is essential. Production of silkworm eggs is classified into

reproductive seed and industrial seed. Reproductive seed are those from which the pure

breed cocoons are obtained. Rearing of pure breed of silkworm is comparatively different as

they are not strong and are easily susceptible to diseases. Industrial seed are hybrids

between two or more races. This is used for production of cocoons on industrial scale. The

steps are given below-

1) GRAINAGES - Grainages are the centeres where silkworm eggs free from diseases are

produced in large quantities. It may produce layings either of the pure races or the hybrids.

2) LOOSE EGGS - Commercially 50 t0 100 months are allowed to lay eggs on a sheet of paper

coated with gummy substance. The egg sheets are soaked in water for 30mint and washed

to loosen the eggs.

3) SEED ORGANISATION AND SEED SUPPLY - The research institutes maintained breeds

stocks of the approved breeds of silkweorms required for production of hybrids silkworms

seeds. Hygienic and ideal conditions for silkworm rearing are provided. Only certified

cocoons are supplied to the grainages to prepare hybrid layings. Only approved hybrid

combinations are supplied to the rearers.

B) SILKWORM REARING:



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The objective of silkworm rearing is to produce cocoons for reeling or for seed

purpose. Rearing of silkworms can be regarded from two points of view- Technical and

commercial. Steps involved in silkworm rearing are as below -

1) DISINFECTION - The rearing room and appliances should be thoroughly cleaned with

water to removed dirt, dust and dead larvae to prevent infecton.

2) BRUSHING - It is done to seperate the newly hatched worms from the shells of their eggs.

3) BED CLEANING - For the health of the silkworms, the litter piled on the rearing beds with

waste mulberry leaves are removed periodically.

4) SPACING - It is donr privent overcrowding of the worms and to provide space for their

orderly growth.

5) MOULTING - The silkworm casts of its skin four times during bits life. There is no feedinghere for uniformity of its growth.

C) SILKWORM DISEASES AND PEST:

THere are four main diseases of silkworm namely: Pebrine, Flacherie,

Muscardin, Grasserrie.

A) PEBRINE : This is one of the most destructive diseases of silkworm and is the main cause

of the decline of silk industry. It is caused by a Protozoan parasite nosema bombycis.

B) FLACHERIE : It is caused by faulty rearing. It is caused due to high temperature, Bad

Ventilation, Bad leaves, over feeding, overcrowding etc.

C) GRASSERIE : It is caused by borrelina virus. It is a kind of dropsy which may appear in any

stage of rearing. Steam or hot water sterilization of rearing tools is desirable.

D) MUSCARDINE : This is caused by a fungi which gets lodgment in the body of silkworm and

pentrate in all diretions with its network of blood sucking hyphae. White muscardine is

casused commenly in India. It is caused by Beauveria bassiana.

E) The common silkworm pest are Uzi fly, yellow fly, Dermestid beetles, and predatorsare

lizard rat etc.



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DISINFECTION & HYGINE IN SERICULTURE

Disinfection is the process that kills the germs and application of scientificknowledge to the preservation of health and prevention of the spread of

diseases or the science concerned with the prevention of illness and

maintenance of health is known as hygiene. During the operation of silkworm

rearing, there is a possibility of disease occurrence in silkworm cocoon crop.

These diseases are transmitted either from parents or through horizontally.

Hence disinfection is an important and necessary step to ensure healthy and

successful silkworm rearing. The objective of the disinfection is total

destruction of disease causing pathogens. Several bacteria, virus, fungi and

protozoan cause silkworm diseases. These pathogens released by diseasedsilkworms easily accumulate and spread in the environment. They can survive

for long periods, even fifteen years, under congenial conditions. The spores of

pathogens like fungi are very light and easily carried by wind and can spread

from one rearing house to another. Many bed-disinfectants have been

formulated to prevent the silkworm diseases but there are no curative

methods for any silkworm diseases. Therefore, prevention of the disease is the

best cure which could be ensured by proper disinfection and maintenance of

hygiene in and around rearing house/room. Disinfection can be done by the

following methods:

Physical method

Physio-chemical method

Chemical method

PHYSICAL METHOD:

Disinfection by physical methods can be done by washing andexposure of sunlight. The microbicidal activity of sunlight is mainly due to the

presence of ultra violet rays. The sunlight also generates heat hence the ultra

violet effect and heats both combing sterilization. The ultra violet rays provides

natural method of disinfection by killing bacteria suspended on the surface of

the articles and heat acts by oxidizing effects as well as denaturation and

coagulation of proteins The rearing articles must be washed thoroughly with

clean water and kept in bright sunlight at least for six hours. Sunlight provides

natural method of disinfection by killing the bacteria on the surface of the



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articles. The sun light is more effective in killing the bacteria due to the

combination of ultra violet rays and heat during bright day light.

PHYSIO – CHEMICAL METHOD:

A physio – chemical method adopt both physical as well aschemical. Fumigation of a rearing room by streaming formaldehyde is an

example of physio- chemical method of disinfection.

CHEMICAL METHODS:

Disinfection done with the help of chemical, to eradicate the

germs by using chemicals from the environment, is referred as chemical

method and the chemical used for the purpose is known as chemical

disinfectants.

Chemical disinfectants are products that kill germs (harmful

bacteria, viruses and fungi). All disinfectants kill bacteria called bactericidal.

Some also kill fungi (fungicidal), bacterial spores (sporicidal) and/or viruses

(virucidal). An ideal chemical disinfectant should have following properties:

Wide spectrum of activity

Active at any pH

Stable

Long self life

High penetrating power

Non-toxic, non-allergic, non-irritative and non-corrosive.

Not have bad odour

Not leave stain and after all

Not be expensive & easily available.

The efficacy of disinfection depends on contact time, prevailingtemperature, concentration and type of ingredient, quantum of microbial load

and presence of organic matter. The chemical disinfectants at working

concentration rapidly lose their strength on standing hence it should be

utilized immediately after preparation of the solution.

Disinfectants

1. Formaline: It is commonly used disinfectant in sericulture.

It is commercially available as 36% formaldehyde solution. It is more effectiveat the temperature of 25 C and 70% humidity and further efficacy increases as



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the temperature rises. A mixture of 2% formalin + 0.05% detergent is an

effective solution that can be used for disinfection purpose. Formalin is

effective only if the rearing house is airtight. It has a strong irritant effect on

eyes and nasal mucous; hence utmost care is required at the time of

application. It is advisable to wear gloves and gas mask at the time of formalinspray.

2. Bleaching powder: Bleaching powder releases nascent oxygen and chlorine

which have bactericidal action. Hence for an effective disinfection, a high grade

bleaching powder with 30% active chlorine content must be used. It should be

stored in sealed bags away from moisture. Under wet and contact conditions

the action of bleaching powder is very effective. Therefore surface and the

walls should be drenched with this solution. A 2% bleaching powder mixed

with 0.3% slaked lime is effective and can be sprayed.3. Slaked lime: Slaked lime has antiviral properties and it also absorb moisture.

Hence, it is a very effective bed disinfectant, especially against virus. It can be

used to regulate bed humidity and maintain hygiene in the rearing room.

Application of lime dust in combination with bleaching powder in and around

rearing houses and premises improve hygiene in the environment. For disposal

of disease or dead worms, slaked lime is more useful than formalin solution.

4. Chlorine dioxide: Chlorine dioxide is marketed as Sanitech and is an ideal

disinfectant for Sericulture. The disinfectant available at 20,000 ppmconcentration is a strong oxidizing agent is diluted to 500 ppm and cause

damage by oxidising sulfydryl groups of enzymes. . It is stable and can be

activated at the time of disinfection with activator. It has a characteristic odour

and non-corrosive at the suggested dilution.

Materials required for disinfection:

Disinfectants, detergent, sprayer ( Rocking, Gator, power sprayer

or multipurpose pump),buckets measuring jars, weighing scale, gas mask,

metal pans, room heaters, hand glove and muslin cloth.Calculating the area of rearing house:

Floor area = Length x Breadth ( of the floor) Example:

Length=20’, breadth =15’ Area=20x15=300 sq ft =28 m2

Estimation of quantity of disinfectant required:

Solution required for spraying inside the rearing house.

Solution required to disinfect appliances inside the rearing

house= 25% of floor area.



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Solution required for spraying outside side the rearing

house= 10% of floor area.

Total solution required =a+b+c. 2 lit/sq mt or 185 ml/sq ft

floor area is required.

For above example,

28 x 2= 56 lit of solution is required for disinfection inside

the rearing house

56 x 25%=14 lit solution is required for disinfection of

appliances.

56x 10% = 5.6 lit solution is required for disinfection outside

the rearing house. Total solution required = 56+14+5.6= 75.6 lit =75 lit.

Disinfectants:

1. 2% belching powder in 0.3% slaked lime, or

2. 2.5% sanitech (Chlorine dioxide) in 0.5% slaked lime, or

3. 2% Formaline + 0.05% detergent solution.

Preparation of solutions:

1.Preparation of bleaching powder solution: To obtain 2% solution of

bleaching powder, 20g bleaching powder with active chlorine content of

30% and 3 g slaked lime in one lit is 2% solution is used. To prepare 75

lit solutions, 75x20=1.500 kg bleaching powder + 75x3=225 g of slaked lime

is required.

2. Preparation of 2.5% sanitech solution: Preparation of 1 lit Sanitech,

Solution A: Add 2.5 g of activator crystals to 25 ml of sanitech solution stir

and allow for 5 minutes to stand the solution till colour changes to yellow.

Solution B: Mix 5 g of slaked lime powder in water and make it up to 975 ml

of water. Mix solution A and Solution B.

To prepare 75 lit of sanitech in 0.5% slaked lime solution, Solution A:

75 x 25= 1.875 lit sanitech concentrate solution+ 75 x 2.5=187.5 g activator.



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Solution B: 75 x 5 =375 g slaked lime Mix and add 75-1.875=73.125 lit water

3. Preparation of 2% Formalin solution: One part of 36% formaldehyde

solution = 17 parts of water is 2% formaline solution. Add 05 g detergent per lit

of Formalin. To prepare 75 lit of 2% Formalin, 75/17=4.17 lit. Take 4.17 litFormaldehyde solution and add 75-4.17=70.59 lit of water. Add 75 x 0.5 = 3.75

g of detergent.

Disinfection: The North Indian states are bivoltine zone and bivotine

silkworms are more susceptible to diseases compared to multivoltine

and cross breed silkworms. Further, pure breeds are more susceptible to

diseases than hybrid. To avoid the loss due to diseases in silkworm

rearing prevention is best method. Effective disinfection of rearing

house, its surrounding, rearing appliances and maintenance of hygienic

measures are most crucial in the silkworm rearing.

Any of the disinfect viz, 2 % bleaching powder in 0.3 % slaked lime, 2.5

% Chlorine dioxide in 0.5 % slaked lime or 2 % formalin + 0.05 % detergent

solution may be used for disinfection.

Disinfection of rearing house, appliances, etc., inside the rearing house:

Spray disinfectant using powerful jet sprayer, the required quantity of

disinfectant, uniformly to drench all parts of rearing house inside

appliances and outside. Keep the rearing house closed for a minimum

period of 6 to 10 hours. After 18-24 hours, shift the rearing appliances out

of rearing house and sundry for 10 – 12 hours. Disinfect bamboo

mountages with 2% formalin solution. Use 1-2% bleaching powder

solution for disinfection of plastic collapsible mountages.

Silkworm rearing using the mulberry shoot does not require the rearing

trays but uses the platform. Rearing trays are the main source of infectious

agent and most difficult and expensive to achieve disinfection. To avoid this,

changing over to rearing silkworm on shoot is advantageous. This method does

not require additional disinfectant for appliances as only the rack and nylonnets are used.

Fumigation:

Disinfection in the gaseous form is known as fumigation and is

effective only in air tight rearing rooms. The rearing room and equipments

can be disinfected at a time by this method.

Formalin can be used for fumigation. The quantum of formalin can

be calculated as per the size of the room and diluted 4-5 times. It may be kept

in a pan, put on a charcoal stove/ sigri in the rearing room and ready for



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disinfection/ fumigation. Formaldehyde can also be used which sublimates on

heating and releases formaldehyde fumes. In order to fumigate an area of 10

cubic metres. About 60 gm of paraformaldehyde is required.

The rearing room should be kept closed after disinfection for at

least 24 hrs. All the doors and windows should be opened 1 to 2 days before

use to allow free circulation of air.

Disinfection prior to brushing:

Disinfection process should start 4-5 days prior to brushing. However,

the eggs may be incubated in separate disinfected incubation room.

Five days before brushing:

Clean the mounting hall, rearing house and appliances and make all

free of dust, wash in water and sundry all appliances. Arrange them inside therearing house.

Dipping in disinfectant:

Disinfect the rearing appliances that could be disinfected with 2 %

bleaching powder in 0.3 % slaked lime solution by dipping them for 10

minutes in the solution in a disinfection tank. A tank of 2 feet depth and 4

feet diameter is suitable for disinfection. Prepare the disinfectant solution to

fill half of the height of the tank. To determine the quantity of disinfectant

solution to be prepared in the tank, calculate the volume of the tank usingthe formula 22/7 * r

2 h (where r is the radius and h is the height of the tank)

Disinfection by spraying:

Beside disinfection of appliances by dipping in disinfectant, disinfection

can also be carried out by spraying the disinfectant.

Spraying the appliances using 2 % formalin + 0.05 % detergent solution

or 2.5 % of Sanitech in 0.5 % slaked lime or with 2 % bleaching powder in 0.3 %

slaked lime solution @ 35 ml/sq ft surface area or 700 ml for a tray of 3.6 feet

diameter is also effective. After the spray, put them together and keep

completely covered with vinyl sheet for a minimum period of 6 hours can also

be disinfected by this method.

Cleaning of rearing house and appliances:

Immediately after the completion of the silkworm rearing and

disposal of the cocoons, all the refuse of the rearing including dead larvae and

pupae should be collected in one place inside the rearing house. Disinfect the

rearing house including this debris with 5% bleaching power solution and

dispose off by burying at 2 ft. depth or burning out the rearing waste.



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Disinfection process should start 4-5 days prior to brushing.

However, the eggs may be incubated in a separate disinfected room.

Four days before brushing:

Sun dry the appliances. If the prevalence of viral diseases (Grasserieand flacherie) were high during the last crop, spray 0.3 % slaked lime in water

(3 g/lit) to the rearing house and appliances @ 2 lit / sq m floor area +

additional requirements. Sun dry the appliances after 1-2 hour of spray.

Three days before brushing:

Conduct second disinfection of rearing house and appliances. Shift all

the disinfected appliances into the disinfected rearing house and arrange in

the room. Disinfect the rearing house and appliances by spraying 2 %

bleaching powder in 0.3 % slaked lime solution or 2.5 % sanitech in 0.5 %

slaked lime or 2 % formalin + 0.05 % detergent solution. The quantity of

disinfectant solution required is calculated and sprayed as per the first

disinfection. After disinfectant spray, keep the room closed preferably for 24

hours. The second disinfection may follow the first if the gap between the

two is not much.

Two days before brushing:

Dust 5 % bleaching powder in slaked lime powder @ 200 g/sq.m at the

entrance of the rearing house and the passage to it. Sprinkle water @ 1

lt/sq.m floor area. Open the windows of the rearing house and ventilate to

drive off all the odour of disinfectant. Prevent contamination of rearing house

and appliances.

One day before brushing:Arrange appliances for chawkie rearing and maintenance of hygiene. Keep the

rearing room and mounting hall closed and open only one day before the

larvae are to be shifted.

Maintenance of Hygiene in rearing house:

Sprinkle bleaching powder and slaked lime mixture

(1:19 ratio) at the entrance of the rearing room and



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its surroundings, three days before to avoid any

secondary contamination.

Place foot mat with bleaching powder and slaked

lime mixture (1:19 ratio).

Floor of rearing room must be swapped with 2%bleaching powder and 0.3% slaked lime solution.

Change foot wear before entering in rearing

room. Wash hand with disinfectant solution/

germicidal soap before entering in the rearing room

and after each feeding/cleaning.

Maintenance of Hygiene during silkworm rearing:

Maintenance of hygienic conditions during rearing facilitates in

preventing the entry of disease causing pathogens from outside and also

checks the spread of diseases. Following precautions are needed for getting

good cocoon production:

1. Entry in the rearing room should be restricted.

2. Persons entering the rearing room should wipe their feet on foot mat

and wash their hands with a solution containing decol or detol solution.

3. Diseased and dead larvae collected during rearing should be put into

lime containers.

4. Compost pit should be prepared away from the rearing house.

5. Rearing appliances should not be borrowed.

6. Paraffin paper and old news paper should not be used after one

rearing.

7. Store mulberry leaves in a separate room with separate entry from

outside.

8. Dust slaked lime on worms settled for moult.

9. Dust bed disinfectant half an hour before resuming the moult and 4th

day of the final instar as per the schedule.



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10. Pick diseased and non spinning larvae from the mountages and

dispose into 2% bleaching powder and 0.2% slaked lime mixture.

Different diseases of silkworm and their management

Life cycle of a mulberry silkworm-

Mulberry silkworm reared in north india are mainly bivoltine.Disease that may cause severe harm to

the worms are as follows-

A. Protozoan diseases

The protozoan diseases of silk worm is called Pebrine because of the characteristic pepper -

like black spots appearing on the infected silk worm.This disease is caused by the infection of the

protozoan Nosema bombycis Nageli .

Symptoms

All stages of mulberry silk worm are affected by the pebrine spore.



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Control measures

a. Rearing only disease free laying prepared in grainage after mother moth examination.

b. Removing disease larvae from the rearing tray and burning them.

c. Disinfecting rearing room and rearing appliances with 4 to 5% formalin or bleaching powder to kill

spore that may be present in the appliances

B. Bacterial diseases ('Flacherie')

Formerly, all diseases with the symptoms of diarrhoea and vomiting were collectively called

'Flacherie' and were believed to be caused by bacterial infection. Later on it was found that

infections of bacteria were not always associated with flacherie. (Photo )

Bacterial Oacherie or Gastric injury flacherie

This disease considered to be caused by multiplication of bacteria in the alimentary canal

which has become weakened due to bad environmental condition.

Causative organism Various pathogens have been suspected to be the causative organism. In the

initial stages of the disease Streptococci, in the advanced stage approaching death, coliform bacteria

and in dead worms Proteus group of bacteria have been isolated from the diseased larvae.



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c. Symptoms

The diseased larvae show the following general symptoms of flacherie are loss of appetite,

sluggishness and retardation of growth and softening and inelasticity of the skin.

d. Control measures

This control measures consists of the following.

i. Provision of optimum environmental conditions and providing good quality leaves during rearing.

ii. Avoidance of unhealthy larvae by incubating eggs at uniform optimum temperature (22-25°C) and

humidity (80-85% RH).

iii. Disinfection of rearing house and appliances with 2% formalin.(Photo required)

3. Grasserie disease

This viral disease is called jaundice as the infected larvae appear yellow in colour and excrete

white faeces filled with viral polyhedra.

There are three different kinds of polyhedrosis disease nuclear polyhedrosis, midgut cytoplasmic

polyhedrosis and mid gut nuclear polyhedrosis



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a. Control measures

Hygienic rearing, avoidance of unsuitable leaves, giving proper ventilation, removal of dead

and sick larvae and sterilization of rearing room with steam or 2% formalin or bleaching powder.

This disease is controlled by oral administration of nalidxic acid, p-propiolactone, p-

aminobutyric acid and tropical application of Imagine.

D. Fungal diseases

Fungal diseases of silkworm are called Muscardine. The characteristic feature of this disease

is the mummification of the infected larvae till and after death by deposition of calcium oxalate

salts. Hence, this disease is also called calcino.(Photo required)

Symptoms

The common symptoms are the following:

i. loss of appetite, lag in growth resulting in 'unequals' in the rearing bed,

ii. oily specks and spots on the skin which may have black or green margin,

iii. diarrhoea, vomiting, shrinkage of body and inelasticity of the skin,

Control measures

If muscardine attack is noticed, control measure have to be taken both during rearing and in

between successive rearing.

i. Infected larvae and litter must be removed immediately before formation of conidiospores on

them and burnt. Infected and healthy larvae can be separated froin each other by spreading a net

with fresh leaves over the rearing bed, when healthy ones alone crawl up to the net.

ii. Provision of good ventilation and low moisture in the rearing room.

iii 0.4% to 0.8% formalin is mixed with burnt paddy husk in the ratio of 1:10 and spread over the

rearing tray form 30 minutes for one or two days particularly after the molt.

iv. High grade chlorinated lime (containing 0.1 % chlorine) is sprayed till the larvae are wet. After half

an hour fresh food is supplied on a net and healthy larvae come out to feed and by this treatment

any spore on their body is prevented from growing.

v. A number of chemicals have been newly evolved for surface disinfection of the larva to prevent

muscardine growth. These include, Dithane M -45 with lime, aliband, sunace, kinuban, pafsol,

kabinuron, chemichlon, shinsha dust, benzoic acid and benzoal knonium chloride. Central Silk Board

(CSB) has evolved resham keet ooshash for this purpose.



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Introduction of sericulture at RSRS,Sahaspur

Regional sericulture research Station(RSRS), Sahaspur is a research station which works for teimprovement of the sericulture in India. Its nodal centre is at Mysoore. Area under mulberry

plantation is about 9.824 acres along with other buildings such as rearing house, administrative,

seed house etc. include 3.664 acres. the total area of the station is about 15.62 acres. It runs many

research programs as well as many training programmes are also conducted here. some of the

projects running over here are as follows-

1. Silkworm breeds to evolve viable and productive silkworm genotypes/hybrid for sustainable

bivoltine sericulture

2. Evaluation of elite bivoltine silkworm germplasm under different agroclimatic conditions

3. All India silkworm germplasm evaluation programme

4. Maintainance of GPB

5. Maintenance of parental line and breeder stock



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Reference

1 .Mulberry cultivation – Chaudhary P.C.

2. Integrated Skill Development Scheme Studies mater- Dr. Anil Dhar

3. Hand book of sericulture –S.B Dandin

sericulture priject

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