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
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