Ex. No.1 Date :

STUDY OF DIFFERENT SPECIES OF SILKWORMS AND THEIR HOST

PLANTS

Silk is a natural proteinaccaus fiber secreted by silkworms in the form of fine

thread. Many insect and non-insects are known to produce the silk. Out of these, four

species of silkworms have been commercially exploited to produce the silk. India is the

only country producing all the four types of silks.

l. Mulberry silkworm, Bombyx mori (Lepidoptera bmnbycidae)

The mulberry silkworms is the most common source of silk raised domestically.

Egg is oval with flat sides. Freshly laid eggs will be yellow or pale yellow in

colour. Larvae are glabrous and elongate with a mediodorsal horn on eighth

abdominal segment. The body of the larvae consisting of head, thorax fUld

abdomen, has three pairs of thoracic kzs and five pairs of abdominal legs. The

larvae form lens CDcoons. Shape and colour of the cocoon vary according to the

race. Cocoon is composed of a single contmuous reelable thread ranging from 400

to 1500 meters in lengdI depending on the rax, Therefore can be industriously ree!

t'-<i to produce raw silk. The pupa is obtect. The moth is milky white in colour,

medium sized and it has white coloured fore and hind wings with smoky wavy

1ines. The apax of the fore wing is slightly elongated and curved.

2. Eri Silk worm Samicoynthia ricini ( Philosamia ricini) Lepidoptera: Saturniidae)

Eggs are avioid and candida white caterpillars on batching are yellowishih green.

The grown up larve is yellowish white robust pocesing socoli all over the body.

The larve constructs dense firm open cocoon silk is not reelable. Pupa is obtect.

Moth is balck / cahcholate brownish , balckish or cahchoalte ground colour

having ocellus and pterostigma.

3. Tropical tasar silk worm, Antheraes mylitta ( Lepidoptera :saturniidae)

Egg are oval and dorsoventrally flattened, Larvae is typically emciform green,

robust with scoli and shining spots. Cocoon is dense, firm possesing ring

supporting stalk or ~uncle. Colour varies. The filamemnt is continuous measuring

500 to 1300 metres in length. Pupa is obtect.

Moths show varied colours and exibit distinct sexual dimorphism males and

females are bigger with distended abdomen and narrow bipectinate ,ultannae

being grey and yellow in colour. The wings in both sexes are provided with a

transparent eye spot near centre,

4. Muga silkworm. Antheraea assamensis (Lepidoptera: satumiidae )

Eggs are brownish, oval and dorsoventrally flattene without streaks. Caterpillars

are green with brown head and semidomesticated, Cocoon colour varied from

golden to ii~ brown.. They have rudimentary peduntule. The silk is reelable. Pupa

is obtect.

Adults are larvae comparable to tasar moths. Wings have a small transparent eye

spot at the centre. Here also the females are bigger than males,

Besides the above listed for important insects Coricuila trifenestrata anaphe spp.

Fagara silk. Attacus atlas and coan silk Pachypasa otus are also known to yield

silk. Among non insect Pinna suamosa ( bivalve ) and Nepi madaoscarensis

(spider ) are the two important sericigenous species.

HOST PLANTS OF SILKWORMS

Larvae or caterpillar is the only feeding stage in the He cycle of all the four

commercially exploited silkworms.

1. Larvae of Bombyx mori is mostly monophagous as it has mulberry (moros spp) as

its only food plant. Mulberry leaf protein is the source for the silkworms to bio-

synthesize the silk which is made up of two proteins. Mulberry is gr9wo as bush

in tropical countries and tree in temparate countries. 11Iere is considerable

amount of confusion in the taxonomy of genus Moros. However, there exist

several species and varieties under this genus, like Moros serrala; Moros alba,

Moros 'nigra, Moros indil.:a, Moros laevigal, Moros sen'ala, Moros mullieaulis

etc. Moros alba is generally found in tropical and sub- tropical regions.

In Karnataka the varieties of mulberry viz, Victory-I (V-I) Mysore Local, kanva-2

(M5). S-54, S-30. S-41 and S-)6 are being cultivated by the sericulturists. S-13

and S-14 are the varieties recommended for rain fed areas.

Mysore local has lobed leaves, yields less but well-suited to rain fed area. It is

popular in the traditional sericultural belts of Karnataka

Kanva-2 (M-5) is claimed to be superior to 10c~lstrain and yields 40 per cent

more foliage. It has entire leaves with serrated margin and responds well to

fertilizers with serrated margin and responds well to fertilizers and irrigation.

Victory-I (V -I) is found to be superior to Kanvo.-2 and yield about 25-30 pet cent

more leaves. It has broad leaves with good keeping quality.

S-54 is another variety; evolved through selection which yields 40-60per cent

higher leaf yield compared to farmer varieties. It has broad boat shaped entire

leaves with blunt serrations at the margin.

2. Larva of Samiatynlhia rieini is polyphagous.

However it has strong preference for leaves of castor Ridnus communis. It also

feeds on Kesseru, Heleropanax jragans. Tapioca, Manihol u/ili.mma, papaya,

carica, papaya, champa, Plumoria acut!{i.Jlia, barkesseru, Ailenthus execlsa,

payam, Evodia flaximfolia and kanagalu (temple tree), plumeria alba.

3. Tasar larva is polyphagous. The tropical tasar silkworm primarily feeds on the

leaves of Asan, Terminalia lomenlosa; Aryun, Terminoiw or/una: saL S/iorea

rohusla; Ztz}phus jlljub,'ber,\ZiZ)phus mauritiarp and anjan., Hardwlckw bma/a,

Secondary host plants includes Termmaha cllI:'bula. The/ohm. 1'. catappa. T

panieulata, Syzygrum cumim (Jamun), LegeslrmlllQ pamglora (sidha), Bautrinia

variegala (kechar).

4. Muga silkworm Antheraea assamensis is also polyphagous Larva feeds primarily

on evergreen som, Machilus bomhycina and saolu, Listsaea polyantha. The other

food plants of muga include Listsaea citrate, Cinnamonum obtusifolium and

symplocos grandiflora, Michelia champaka (sampige), Tamarandus indica

(tamarind), Michelia oblonga (champaka).

DIRECTIONS

1. Observe various species of silkworm and draw neat diagram

2. Observe the food plants provided and make habit sketches of them. Prepare

herbarium of an) of the food plants of silkworm.

Ex No. 2 Date:

PRUNING AND STORAGE

Cultivation of mulberry assumes priority in mulberry silkworm raising Morus

Alba is grown as rain fed in arid and semi arid zones receiving 15 to 30 inch rainfall from

May to October during South West and North East monsoons. It can be cultivated in

varied types of soils namely red loamy to black cotton soils.

Land preparation: Land should be ploughed deeply and thoroughly to loosen the soil, to

still the pests and weeds and to facilitate easy rooting.

Variety:

M-5 can be used since it has the following commanding advantages over local variety.

1. Thrives well under rain fed conditions.

2. Yields 25% more

3. Responds well to manuring

4. Leaves are succulent and moisture

5. Easy propagation by cuttings and grows vigorously.

Shoot selection /cutting preparation: planting material is the land wood cutting of one

year old selected the shoots should be of pencil size thickness and the length should be 20

to 22 cms with 3 to 4 eye buds. The lower goes into the soil should have a slanting cut.

Planting

Planting can be done eight in row system / pit system. June -august is the best

season.

Cutting should be planted in a slanting position with one eye bud above the

ground level. Sapling raised in nurseries can also be used.

Spacing: Varies depending on the water availability and type of garden normally pit

system of planting is advocated in view of quality leaf production.

Pit system 0 9 x 0.9 m or 0.6 x 0.9 m

Row system 0.45 x 0.15 m (irrigated)

Kolar system of planting: shoot harvesting of mulberry is common on Kolar district.

Hence, dense planting with a spacing of 30cm x 10 cm is done.

Manuring: 5 to 10 tons of FYM or compost per hectare (rain fed) / 10 to 20 tons of FYM

or compost per hectare irrigated) should be given at the time of annual pruning as basal

dose under irrigated conditions.

Fertilizers: 50:50:50 Kg of N, P2O5 and K0O has to be given as basal dose during June-

July and 50 kg of N as top dressing in October after harvest for rain fed mulberry per

hectare per year Fertilizer schedule corresponding to five harvests for irrigated mulberry

is as follows:

After Fertilizer in Kg /ha

N P2O5 K2O

I Harvest 60 60 60

II Harvest 60 - -

III Harvest 60 - -

IV Harvest 60 60 60

V Harvest 60 - -

Total 300 120 120

Irrigation should be given once in 8-10 days ( sandy loam soisl ) or 15 days ( clayey soils

to a depth of 1/12 acre inches)

Ridging: Ridging between mulberry rows and plants helps in wetting and prevents water

run off thus improves water penetration.

Mulching: Pruned mulberry branches sugarcane thrashes can be spread in between

mulberry rows as good surface mulch. Green manure crops like cow pea, horse gram, or

dhaincha can be grown in between mulberry rows which also serves as mulch.

Weeding: As weeds compete with mulberry leaves for nutrients and water, periodical

weeding should be done either by hand writing or mechanical methods, Weed free

condition is very important to prevent the disease and pests in mulberry.

PRUNING OF MULBERRY

Pruning: "Methodical removal of certain branches' of mulberry plant to give size and

shape to the Plant"

1. It is done to give proper size and shape to the plant.

2. To increase leaf yield

3. To drive nut rents for optimum production of foliage

4. To facilitate intercultural operation easy.

5. To facilitate intercultural operations easy.

6. To synchronies leaf production for silkworm rearing.

Mulberry plants are pruned in different ways. Three methods of pruning" are

practiced According to climate, geographical condition, forms of silkworm rearing and

method of leaf harvest.

1) Bottom pruning 2) Middle pruning 3) Stepwise pruning:

Bottom pruning: (Annual pruning: mulberry shoots should be spurned during July –

August at 10 -15 cm above ground level for free branching and maximum bush

development. This is practice in both irrigated and rain fed pit system garden.

Middle pruning: Mulberry shoots should be pruned at 90-cm height above the ground

level at first shoots harvest and there on during January in irrigated pit system garden.

Stepwise pruning: The shoots are cut at different heights. Shoots are cut to the ground

level once a year middle cut after every two crops. This will give more yields than

frequent bottom pruning. It is followed only in irrigated mulberry garden.

Harvesting of mulberry: The method of harvesting mulberry depend on the rearing

practice in vogue.

There are three methods of harvesting.

a) Leaf picking: Mulberry leaf is plucked in irrigated as well as rain fed pit system

gardens ."In this method the leaves are picked individually from the plants. The terminal

bud and the axilary buds are allowed to develop further. In India, the leaf picking starts

about 10 weeks after bottom pruning and the subsequent pickings at an interval of about

7 to-8 weeks thus obtaining five to six harvests per year.

b) Branch harvests: The branches with leaves arc out from main stem and fed to the

silkworm after third mould. It is practiced in Kashmir, west Bengal and parts of

Karnataka.

c) Whole shoot harvest: This system is practiced in Kolar region of Karnataka and

Malda district of west Bengal in India from row system gardens. The entire shoots are out

close to the ground level and fed to the worms after third molt. Clipping of terminal bud

helps for uniform maturity of the leaves on the plant. The shots are generally harvested

at an interval of 10-12 weeks, obtaining four to five harvests in a year. Therefore the

leaves should harvested with in cooler hours of the day in the morning 8-10 AM or

evening after 5.00 pm

Leaf yield : By leaf picking an average of 8000-10000 of leaves is obtained per annum

per hectare. In irrigated mulberry generally shoot harvested at 8-10 weeks intervals thus

getting 5 crops a year amounting to 30,000 Kg of leaves per year per hectare.

Selection of leaves: Suitable leaves are harvested depending on the larval instar.

I Instar top 3rd, 4th, 5th leaves

II Instar top 4th, 5th, 6th leaves

III Instar top 5th, 6th, 7th leaves

IV & V Instar mature leaves

Leaf storage: The fresh mulberry leaves are more palatable and nutritious to silkworms.

The individual leaves on harvest are collected in baskets, covered with wet gunny cloth

sand transported to rearing house. The harvested leaves should be preserved in moist,

cool and clean place in order to preserve the succulence. During long period of storage,

considerable nutrition changes take place in the leaves. Thus the leaves become poor in

their nutritive value. These leaves arc preserved is cool in their nutritive value. These

leaves are preserved as cool and moist as possible The ideal atmospheric condition as

temperature below 20° C and over 90 per cent of relative humidity, Leaves should not be

helped but spread loosely in layers and covered with get gunny cloth. In summer the leaf

should be preserved in wooden leaf preservation.

DIRECTION:

1. Prepare the given piece of land by digging for planting mulberry

2. Practice selection of cuttings and preparation of cuttings for planting

3. Study and practice different methods of planting mulberry and sketches.

4. Practice bottom and middle pruning of mulberry.

5. Harvest mulberry leaf suitable for different instars and learn the method of

storage.

6. Write down the systematic package of practices to be followed for rain fed and

irrigated mulberry both under pit and row system.

Ex. No. 3 Date:

PESTS AND DISEASES OF MULBERRY AND THEIR MANAGEMENT

Mulberry being an evergreen perennial plant with luxuriant foliage affords an

unlimited source of food, nutrition space and shelter for a variety of insects. Some of the

insects in addition to causing damage to mulberry also act as disease carriers aIrl6ng

plants and to the silkworms. These insects infest mulberry crop at different stages and the

intensity varies month of month. Based on the type of injury inflicted to the crop, the

pests have been grouped under root feeder stem borers, sap feeders and foliage feeders.

I ROOT FEEDERS: (Termites Odontotermes Ohesus ( Isoptera : Tennitidae " Termites

are serious pests in virgin land where mulberry planting is taken up. They damage the

cuttings when freshly planted and also grown up plants feeding on the roots.

MANAGEMENT:

(a) Cultural Method:

1. Location and destruction of termite colonies, which is achieved by breaking, open the

mound and removing the queen.

2. Frequent irrigation of the crop

3. Clearing of affected twigs and burning of crop residues reduce the termite population.

(b) Chemical Method:

Treating the mounds with certain insecticides like aluminium phosphide at the

rate of two tablets or phornte 100 at the rate or 50g per mound

II DEFOLIATORS:

I. Bihar hairy caterpillar: (Spilosoma Obliqua ( Lep : Arctidae )

A polyphagous pest serious from November to January. The early instar caterpillars

feed gregariously skeletonising the leaves and disperse during later instars.

Control: collection and destruction of egg masses and young larvae. Application of 0.2

DDVP

2. Grasshoppers: ( Neorthacris Acutices ) ( Orthoptera : Acrididae )

All the grasshoppers, both in nymphal and adult stages, feed on leaves, leaving the mid

ribs and stalks, the sporadic attack by the grasshoppers starts from May-June and

continues till December-January. The intense of the attack will be more in rain fed crop.

Management:

1. Deep ploughing should be taken to expose the egg pods to the natural enemies.

2. Application of 8 Kg fndosldi"311 4% dust on the crop and also on bunds would al

protec-tlon. Care should taken not to harvest the mulberry leaves till 8-10 days to the

residual toxicity.

3. Weevils: Myllocerous viridonus M. discolor ( CoJ : curculionodac)

The adult weev;ls feed from the margin of the leaves. The mature leaves are sub more

attack. Under severe condition, the leaves get skeletonised. Spraying or dustin~

EndosuJj):m. -

4. Root grubs: A.dorelWl versulus

Adult of white grubs or roots grubs damages the mulberry leaves/roots. Management:

I . Adult collection has to be done sta..'1:ing, from May rains hy trapping them to the

trees.

2. Application of Malathion dust mixed in equal quantity of farmyard manure to av

emergence orear!y stage.

III SUCKING INSECTS:

1. Jassids (Empoascajlavesens) ( Hemiptera: cicadellidac)

A sucking insect pest severe during Qctober!~JV1ay, both adults and nymphs sue from

the underside of the leaf causing hopper hurn.

Control: spray 0.02% DOVP (Nuvan)

2. Seale insects: Hard scales: Aonidiella auran/if (Hemiptera: Dia<;pldidae ) Black

Saisselia mgra

TIle scale insects infest the tender parts of the piant in large numbers, dessp nonnal look

foJiowed by fading liTld drying up of the infested shoot or plant. Management:

1. prune the infested parts and bum.

2. Spray the crop with 0.15 ml Dichlorovasor phosphamidon or 1.5 mlofDim!

per litre of water. Safe period 8-10 days. .~--

3. Thirps: (Pseudodendrothnps mort) ,

( Thysanoptera : Taeniothnps o!aratris Thripidae Heplothrips c%ralus T glycmes

T. melanicornis

"Dle nymphs and adults despair the plant by way of laceration. As a rest!

white spot appear on the leaves. v control: spray 0.05% DDVP

4. Mealy bugs: Afaconellicoccus hirstustus (hemiptera :Pseudococcidae)

Mealy bugs infest render parts of the plant including leaves ai,d suck the sap, resulting in

leaves turning vellow.....and withering.These mealy bugs congregate along midribs and

tenuously, the vigor as well as quality 0 leaves show u£..ward curling&become deformed

it has been incriminated with spread ofTukra disease of mulberry.

Management --- . ~_ ..

I. In case of severe infestation by mealy bugs prune the infested parts and burn, so that

spread and multiplication of the pest population can be minimized

2. Spray_l~_!!ll o[dirnethoateor } .25 ml ofmonocrotophos per liter of water and a safe

period

of leaves 10 days is allO\v~ -- ..

3. Spidermites (J'etranychus telarius) } (Tetranychidae:Acari) -0 c: v:

(Hotetranychus eugomamersis) }

("' ~ ,',' '" '{ r, ,',J ';;

IVti Stem borers: lndarbeia quadrinotata (Lepidoptera: Metarbelidae)

',.~

The bark caterpillar infestation can be easily detecte.d by the prest-"11ce of winding

galleries of flossy web on the stem and near forks or angles of branches. 111e caterpillar

remains in the tunnel at the exiles of branches and move about conceal4s inside the silken

gallery and feed on the bark by scrapping. Heavy infestation retards the growth and

affects the leaf.

Management:

1; Removal oflarvae from galleries on the stem using hooks and swabing with o. I per

cent

" . Malathion.

;:tJjt~~j~l:~.Jt~tor: The grubs damage the shoots by girdling.

Management: Removal of caterpillars by use of hooks I swabing with Malathion.

DISEASES OF MULBERRY

The diseases are classified as fungal, bacterial, viral, mycoplasma, nematode and

defiance disease.

FUNGAL DISEASE

I) Root rots:

a) White rot: Rosellima necatrix

Plant has feeble growth, leaqves are shed extensively and roots begin to rot.

b) Violet rot: Helicobacldium mompa

Leaves have withered appearance collapse of planets during rainy season is

common followed by rotting of roots.

Management: uproot and burn affected plants. Irrigate the garden and srerilizatyion of

the soil using calcium cynide

2. Stem canker : Botryoiplodia theobromer

Greenish – black lesions when on stem which ultimately transform to black

carbonaceous structures.

Management: Cut and burn the affected plants

3. Powdery mildew: Phyllactimia corylea

The leaves show presence white powder which is common in winter "Leaves dry'

after turning yellow brown or black

This disease can be managed by releasing yellov,' bird hcet,:L :nd v,hite spotted

the field. Chemical control can he hrought ahout by usmg Dithanc \1-4" i(l 1%1. Calexin

(0.05%), leaves can bc harvested only ancr a we~of applicatlun of chemicals

4. Leaf spot ('ercospora moricola

Severe In thc~y sea<;on.~1faves devdop spots wilh yellow hah and generally litil

prematurely····· .. /

Management OfthlS disease is possible by picking and burning diseased leaves and also

removal of alternate hosts (weeds). B~';'l?tin (O.2~o) or Difola{Gn spr?y ,

5. Leaf rust: /lecidlUnl mori

Reddish broV.'l rusty spots ~~ the leavtts arc clear cut symptoms of the disease.

Managcn: the same as under leaf spot.

BACTERIAL DISEASE

Leaf blight Pseudomonas mort

Young leaves are wrinkled. distorted and curled. Older leaves have water socked irregu

spots on the ventral surface.

Management is possible by bumung diseased parts. Rot disease: Bacterium manco/um

(B. man)

Rotting of leaves twigs and stem is the typical symptom. Buming of diseased plants is

effc~ti\c m the m,magemcnt

2.

3.

Viral diseases:

Leaf mosaic: Wrinkling ofleaves and shortening, of ShOOl tips are

evident :vlanageTIlcnt Eradicaae H1SCCt 1;.'cctors USIng pest1cIJc~ RC11V)\"C and

hum the disC;lscd

4.

Mvconbsmai disease:

o o

Dwa.rf c!Jse35c: St}lillXi appe:]rance of plants a.s short m!crnodt''; aTe small and

ona.1ged ineguiariy.

Leaves are

Vianagemcnt' Sanle as /{)f viral disease

.:: Nematode disc,ase:

Root knot disease: ,MelmdoKfne inw~mla

Plants have shun led growth as the roots develop knotty g'!!!s

\1aI13gemcnt: pull and destroy <!ned plant parts Dc:>!roy weeds. which serve as

alternate hosts._.~ _

Deficiency diseases:

! } J\ltwgen: Plants are weak and grow siowly Lcavc<; show yellowing. SiC;;, is light

green and slendl","f, the root system IS poorly developed

\~anag'~rnenf: tJse urcCl., ~l!nrnoHlurn nltra!e or ('!/\r~

2, PcHasium: Leaves me coarse I1,Hmg rUc,ty brown patches Stem IS slender and

marginal, ~,corching of k"aves is evident.

'\, lanagcment: l 'se pot:1sh ;(;rti lizer.

~) Phosphorus: Older leaves ShOVi intra-venal chlorosis and defr,liation occurs,

Management: Apply potassIUm fertilizcrs or b<lJanccd N PK

c1 ,l111e micro clements" iL. ~\io. Lu., Fe etc can also -.;ausc deficiency symptoms.

Directions: Examine the displayed pests, damage.o speclluen of mulherry on account of

pests and diseases, Make suitable diagrams of all material displayed and label the same.

Visit mulberry garden, collc!,;t pests, Identify plant parts affected by pests and diseases,

Preparation ofherharis or presen:ation of her bans or preservation of pests is optional and

may be done as suggested.

Ex. No. 6 Date:

STUDY OF LIFE CYCLE OF SILKWORMS

AND THEIR MORPHOLOGY

All the species of silkworms that arc exploited for production belong to order -

Lepidoptera. These undergo complete metamorphosis. Hence all the stages egg larva,

pupa and adult are found in the life cycle of these silkworms.

DIRECTIONS:

Observe carefully the developmental stages of silkworm and draw figures

depicting the morphological features and developmental duration.

A. MULBERRY SILKWORMS

Mulberry silkworms (Bombyx mori) is a highly domesticated commercially

silkworm reared in over 30 countries. In India there are over 200 races maintained but

few have been exploited. This silkworm undergoes complete metamorphosis and has four

stages. VIZ. eggs, larvae pupa and adult. The duration of each stage varies with race,

climatic condition and quality of leaf provided.

Duration of different stages in the life cycle of mulberry silkworm

Stage Multivoltine Uni-bivoltine race

Egg 9-12 Days 11-14 days

Larva 20-24 Days 24-28 Days

Pupa 10-12 Days 12-15 days

Adult 3-4 days 6-10 days

Duration of different instars and moults:

Multivoltine race Bivoltine race

I Instar 3 days 3 days

I Moult 20 hrs 20 hrs

II Instar 2 days 27oC 2 days 27 oC

II Moult 20 hrs 80-82% RH 20 hrs 85% RH

III Instar 3 days 3 days 25 oC

III Moult 1 day 1 days 80%RH

IV Instar 4 days 25-26oC 5 days 22-24 oC

IV Moult 1 day 70-80 % RH 1 day 80%RH

V Instar 6-7 days 9-10 days 20-23 oC

Total 22-23 days 26-27 days 70 % RH

B. TASAR SILK WORMS

The tasar silkworm is generally Bi or Tri Voltines. The incubation period is 10

days. The larvae after emergence move in search of food crawl on to the leaves of the

host plants. The larval period lasts for 30 to 35 days in summer. It is longer in winter.

Larvae pees through four moults and five instars before they become ripe for spinning the

larvae feed voraciously on the larves and continuously defoliate the trees.

The larvae is brown at first and change to green at the second instar. The normal

tasar silk worms at the final instar are green in colour with violet tubercles distributed

over the body. Each larvae at maturity weight 20 to 60 g and measures 12 to 15 cm in

length.

The cocoon is compact and pendued pupal period of the first generation 15 to 20

days. The second generation pupa undergoes diopatise.

The male moths vary in colour from brick red to dark gray while the females may

be yellow to gray or various shades of brown. Emergence of moths takes place in May /

June in the evening hours. After the copulation for 9 hours. Females by eggs for 48

hours. A moth lays 150 to 200 eggs in two days.

C. ERI SILKWORMS

Assam in India is the home of the Eri silk industry. The ERi worm is Multivoltine

in nature, the incubation period is about 10 days laterally takes place in the morning

hours. The newly emerged larve yellow with black segments. There are four molts and

five instars during the larval stage. The larvael period lasts 30 to 35 days. After 5 to 7

days in the fifthe instar , the larve matures , stops feeding and starts searching for proper

place to spin the cocoons. The cocoons spun by worms are open and the filament is not

continuous. The cocoon is not reelable. Coccon is elongate measuring 4 to 5 cm in length

and 2 to 3 cm in width. Pupal period lasts 10 days. Moth emerge in the morning hours.

After 3 to 4 hours of mating a female moth lays 300 to 500 eggs.

D. MUGA SILKWORMS

The golden yellow silk produced by Muga silkworm, Athcraca assama is found

only in Assam in India.

The Muga silkworm is multivoltine and passes through four moults and five

instars. Generally 4/5 crops are raised in a year. Incubation period is 8 days young larvae

immediately crawl up and starts feeding. The young worms are yellowish with black

body markings. The larvae feed voraciously and pass trhough four moults and each the

nature stage. In the final stage the larve is greenish blue with prominent tabercles. The

larval period lasts fro 30 to 35 days. The muga cocoon is golden or light brown 4 to 6 cm

length and 2 to 3 cm broad with rudimentary peduncle. Pupal period last for 10 days.

EXTERNAL MORPHOLOGY OF IMMATURE STAGES AND ADULTS OF B.

Mori.

Silkworm pass through a complete metamorphosis (HolomctaooaI) from egg to

adult stage through two intermediate stages namely larve and pupa.

EGG: Oval, tiny as big as the head of a pin. Smooth and yellow , non hibernating egg

brighter than the hibernating eggs and measure 1 to 1.3 mm in length and 0.9 to 1.2 mm

in width, weight 0.5 to 0.6 mg. the eggs of European races are comparatively large and

heavier. Races producing white cocoons lay pale yellow eggs while races producing

yellow cocoons lay deep yellow eggs. In both the cases the Japanese races lay slightly

darker eggs that Chinese’s races. In case of hibernating eggs laid by bivoltaine and

univoltine races, the egg colour changes and becomes dark brown or purple with the

deepening of the colour of the serosl pigments. The egg is covered by an egg shell called

chorion which is provided with follicular imprints on surfaces. At the anterior end of egg

there is micropyle.

LARVAE: Eruciform, body divisible into head, thorax and abdomen, Freshly hatched

larvaes with larva lustrous black head, dark brown body with hairs, attains maturity in

about 26-28 days.

HEAD: Head formed by 6 highly fused embryonic segments, light grayish – brown, the

epicranium forms the whole upper region of the head, inverted ‘Y” shaped Epicraanial

sulcus. The important appenddagesa re pair of 5 segmented, antennae and moth parts.

Labrum, labiomaxillary complex. Pair of hard mandibles and six paris of ocelli near the

base of antennae.

Mouth parts are adopted for biting and chewing ( mandibukate type) represented

by two hard powerful mandibles for cutting or crushing the food. Two maxilla with 2 or 3

segmented maxillary palpi. Submentium is divided into 3 sculeriteis, mentum very large

and less chitinised part. Prementium is bporne on mentum carrying spinncret and 2

segmented labial palp on either side.

THORAX: This consist of 3 segments

DIRECTIONS:

1. Observe the different parts of pupa and moths (male and female) carefully and dmw

sketches of wings, legs, genitalia end position of spiracles.

2. Study the \\lng venation of male and female moths.

Ex. No. 15 Date:

STUDY OF SILK GLANDS AND DIGESTIVE SYSTEMS OF THE SILKWORM

B mori

Silk glands:

These are transformed .abinl glands;... ,.ctodcrm?Jjn origin, cylindrlcal and tubular with

charactenslicaHv b17l.J1ched nuclei, l~'" af~ 0:1 the rnid

m" tes'in" "n'~ tl,~:;;,nS"';'''\r f'nd'· ·"'i' !-1;';0 '\Ill,~t';(,rlv tIl<' p"lf'''' G'V"':> l'",dn and

l'lp"rJ into th.n

~. ~~ oo _ ~ ,,"I ~~" j,i'l..F"l,""'J.'~j \,,00 .oo _!' t,,~....., t,)!.lJo. < i , il~ ~" '... .oooo.

-.:4.1, ~", .o ~ 11., U .. dt:lt"",_,~ , .. ' "" ' 'll..i.~""

spum::>I'Ct Silk gland. fray be dlYidcdin to three distinct al1teriQf, middle and pcstcrior.

TIle waH sH k n compose.d of thrc'C 13.yers. the tun:l.:tl propn the gland ceUS; ....o.

and ·I.,e tn""ca i'lt:'n" ,~""ico"i!l" t'lC lu''''''n ('flhi' ..

Ut Ulo-:;;r." ., oo l.i;IG",,", .o ~'....,J',,-~.) b It, ,1'.. oo "",- ) \'~,' oo.

. Fibron atrl:f'SCn~'mand instars. Fibroin the silk protein, is

secreted fTC;,.] the posten or f o .::t:: :1,; u reservoir for the maturation of

fibroin and ;:dsosecre!cs.scri~m arou,.'1d the fi~_'nlCanterior region of the silk gland

does not secrete any particular subst;:mc~~ and It $!mpry acts as a pa.,<;s3ge.

A pair of glands called riHipi's or glands is located at the junction ofth~two

aIiterior regions. A \"is~~lJwd 1:, secreted these gland;-; and their enact function is

notclear. H

is believed to hell) i."r adh~ fibrom and sericin together fu"1d hardening

"--------- - -

Digestive system in the larva IS more or less as straight tube from the mauL'! to the arms

divided into three more pa.'1s the forget or stomopacum Imdg'~nt or mesenteron and

hindgent or

.. pt:0ctodacum. 'nIe oral operatunc opens into the mouth cavity which is followca by a

na.rrow pharynx and esophagus. The esophagus is rnarrow at I.llc anlcnor emf and

to',vards the postcrior end. The midget lS a long, wide. Cj hr\dlrlc:al tub;,: narrow at the

po"terior

qld, Digestion and of foud tal,es place mmilly in the Inldgenl /\.n inner layer present

LVi the Inid~tcnt IS the c:H1bra1:1c. "TIle hind gent consists of ih:;- srnaH intcstine~

colon and

iectum,

The malpi~hian tubes are the pmnary organs of excretion. T'ncse tubes arise at the

junction. TI1CSC 'rubes arise at the junction ocsma1Dntestme c.nd colomnthe hind gent

ofthe digestive tract. 'llIe tube ansing en each side of tl}e hind gent is enlarge.d into an

excretory chamlx."I' from which two branches an""'. f the tubes situate-j on the dorsal

side branches future into two tubes. In aU the'"' ar three pairs PviahinhJan tubules. They

run towards the

anterior side, farm back at ultimate LO the~"tu. -

'----

Ex. No. 6 date:

GRAINAGE TECHNIQUES FOR Bombyx mari

Grninagc is the most imp0l1ant aspect of scncultural industrv since the suc.cess of

s:enculrure industry largell.' deD.cnds on !h. e {I'Llalitv silkwGffil C"25 pr;"l"~l.C(1 'n

the g.r!ll:Tl"np .t'7" .. o. 'C'

~ J.I. '" t.,'""..:..--; ",lit- .~_'-li tit ii.!..l ~ Lit?"'"',· - E-;.!:)'"

are~ofnv0t)'pes.'. ReproductIve seed blIndustriai (eommcrcial}scc<l,.b laymg may

coni'ilii'a)

Fg~eggs (colo3JL~19!maJ,~lat~h !~l.'):lL gays) b) Unfef~I!!~ eggs (l:()lQuIJ?ale, do no!

t!JIlltlue and fa:1 to hatch) c) Dead eggs (eggs that die in the middle

ofembryorUcdc:;dci.-n;nt). Grainagic operatIOns should be performed by weB trained

personnel. Grainage must be \veH ventiiated sl!Q.!JI.d !mve enough space for s.eed

cocoon storage, oV!poratloR microscopic examinatIOn, egg !l:"~tInen!,-disinfecting,

refrigi.'fation, incubation etc .. Grainage techniques includes selection, storage anti

preservation of seed cocoons <md preparation of disease frce layings (dft5)_ TIle

common grmnage operations are: .

I. Selection and storage of seed cocoons:...During the process of seicction melted, flimsy,

!JIi.I!ated, uJi pierced., rnam)~!Tl..~ aVId double cocoons arc to be r~iccted and only

good cocoons are selecteEj{lr~urposeThe ,1os"s"orsC!ecteococoor1"s wIll ga";/e to be

removed to facilitate ea.'"' em~l?,~"~ufmoths and preserved at a temperature of 24-25e'c

in smgle layer for obtaining " t maximwn cclosion. Th~ (,;(}(;(}ons.ar~ refrigerated at 4-

7c {{)r3io 5 days-to synchroni~eeclosion

during cross breed layings preparatIOn: Sexing can be- done"aat pupal-:~tage~ _ ..

2. Moth emergence -The moths emerge nomlaHy during mornmg hours withirl_!.2 to

i4A?ys aA~ Sp,i,!lning. FcmaIcs arc heavier tha..'l males. Sexing can also be done at

moth stage by their activity and looking into the genitaha,

.3, Coupling - TIle male and female moths should be wHeeted separately and allowed to

pair for abotJt three hours When males aTe less in number. they can be used for more

than one

mating. M<llE~C~ll} also be presqv~<!~!.5_~~_r.0~} t~1""4?y~_~~"~~~dfor mating.

4. Oviposition: Soon after dcpairing, the female modi should be transferred on to a SIeve

or paper for discharge of waste fluid-meconimn after which it is enclosed in a moth

fU.m:.e! (cellule) on egg card and kept in dark place for 24 hours for oviposition. In

addition to prepa.'1ltion of eg,gs on cards, loose eggs can also be prepared and sold in

boxes containing50 dfls or II to 12 grams of eggs. . .". ~""~,",-"

S. Mother moth examination (MME) Tl1i?j~,Q~steur's method ofpebrine

elimination.After egg laymg the abdominal portion of the female moth is crushed and the

suspefiSTonis examined under microscope and ifit is found positive for the presence

ofpebrine spores, the entire batch ofC'~ laid by that female is rejected. This disease is

oftnms ov,uian in nature. Individual> sample and mnss type mother moth examinat;;:ns

arc G)HO\vcd

8 .o. , Handling ofbi\oltll1c The eggs (au bi.': cold stored by following h' 0'schcdu!

cJrQml.El~llths to 10 months duration, Dei~"dl ' 1 tl~ need the eggs COl

made ~Q l~tch-b}.Jollo\'\ ing Illbcrnatl\J.ll5c~X_l~ \\ llhGut" gi\ liL .. an:-c- t1'catr

the fOllO\ .oo. mg schcdule "I::::\";:""~\'_~~'<). -

Hibernation schudule for 3, 4,6 &: 10 mnn! h~ 1\,l: r (: J .... -

. . -T-::'------,·-:---,-L-·--i'-::::'~-~ "-!"/~_ ':--'--r ."._ "-~~- 'I "-:-:-'---'-r --~,-------' ;--;---:---

r

HlbematlOn I Temp ,In "c ; ·,e 1(;,C il~( :, ','(' ,,'( i,e i C

eriod i '> "(, ! Jo : '> ,</ 1'7 I( ( I 0 f~ <;

f.',' 3 l\,fon't"hs r\"c",~):',') ~~t~,~~_~t"J3C+,,-c,', :,-'l',:' tii-:--,;-r}(l;' iK,1>~i5

J \ "', ~ ~:> J '''- ", _.:,(','.1 s ... p: t',

r---------, ---r---------T··----·,-------'--- .. -- --, .. --

i 4 Months \:t' \'1" ! 10 : 2 i 2 : ,) i -:0

r6MonthSt--0-T'I'-- i()--·T-E~---i-i6-T·I of '-5 \ \

I~l·-----·_· .... __ · + , .. -- .. ~+.~. "--+ ..--- ....

I10 Months :j.q:' ',\'1 50 ! 4U j 25 i 25 ; 60

_~ '" __ .. _L_.,_~ __ .. ---J.., __ , --'--- __ . __ .. _" ~_ _.L.~, _. __ ,.

b, Refrigeration of non-hibernating! artific~:l hatching of eggs

Since these eggs arc not resistant to lov, h:mpcratllr.: n.:frig..:ral1on IS us~mlly a'

tease ofnecessit) the eggs arc coU st ,;A :;~ -:;\, T !' .. ~ 'r. Pcd':Iabi) the c~

,,1\ need to be subjected to refngeratlOn I.,j \."":; > ::: pl!!Ll\:nt:;Uoll stag'

v;:' r' change the voltinism, In cold ~;tor:lg'_' a ImnmJit\ 7"-S()'\, needs to h.:- ensured

since

".., ~ makes ne\vly h:ltchcd s.llk\\orms llrcd soon..:r ~=

'f

6, Egg treatment: 111: eggs afmultiH)!tinc f::C;,;S do n;~t

c,}lmtrics H'

the i.iggs ofunivoltin:.: and bi\ol;m~; ra"y, ;,l!',:, The cges ('fu::~\oI6nc~ bi,'z"ihulL' anel

i~lU1U\tJ; In!..' r~!cc<..;' \\hli:

colour, whJL: hours and d;1rk

mabl lay~ "~, h::(ch by ct~G;L cleC1l

. \,,!i'

indicates that the: egg;,: arc b1bcn:~l:!; methods. \ i2.. h\drochlonc ~;ud.

Hot hydrochlorisation: The eggs an: U1l)PCU Il1 2, in" for n to 1 '~ mmutcs a in shade.

Thcn the cgg cards arc dlppcd m hot Indwell 101ic aChl \\ ithm :'- to 20 hOUI

oviposition. Currently. for acid trGllmcntlf bl\ o:tll1C egg.; I I I n(,-. ~ p Gra .oo. lt)

46,loC is being used i~;r .. ~:~:;; L trc:

batch. i\ft:; .. :f trC:.1tn'Jcnt

7. Disinfection of eggs ·niC eggs arc dlppcd m 2°.) tiJmdm 1','1' 1 to I:' 'iHlt..:S for s

disinfl:cting aitcr which thc\ arc thOl\.mghly \)a~,hcd In \\~ltcr and dried m shad\:

9. Incubation of eggs:

The silkworm eggs have to bc~incubatl':d ,It:l / of2S-26°(' ~nd RH of75·g eggs at body

pigmentatwn st:lgc arc subJected to d:>rk tn::Hmcat (black boxing) to syr development

and tbincrcasc hatching.

Ex. No Date:

PLAN OF A MODEL SILK WORM HOUSE AND REEARING EQUIPMENTS

Mulberry silkworm being completely domesticated is reared in indoors as it

demands certain specific environmental conditions particularly with regard to

temperature and humidity. Therefore the silkworm rearing houses planned and

constructed to provide and maintain proper environmental conditions to ensure high

yields of good quality cocoons.

The size of rearing house is decided by the size of mulberry garden and leaf yield.

The plans of rearing houses are prepared so as to suit the type of rearing. Generally three

types of rearing are known - shelf rearing shoot rearing and floor rearing. Shelf rearing is

popular in Karnataka, since the rearing space required is less compared to other methods

of rearing.

The rearing house planned for rearing about 300-400 layings should ordinarily

have the following accommodation in shelf method of rearing

1. Chawki rearing room: 10' X 12'

2. Leaf storage room: 10' X 10'

3. Late age worm rearing hall: 20' X 20' (with verandah of 5' width on all sides)

4. Mounting worms: 12' X 12'

A silkworm rearer with one acre of irrigated mulberry requires the above space

for rearing.

PLAN FOR A MODEL REARING HOUSE:

1. It should be a rat proof building with a ledge around.

2. Building should have verandah around with glass windows and doors to provide good

ventilation and light.

3. The ceiling of rearing house should generally be made of wood or concrete.

4. Windows should be placed such that there is provision for free passage of air.

5. Orientation of rearing room: The long axis of the building should be north south in

temperate and subtropical region and cast west in tropical regions.

Rearing houses constructed with mud walls and thatched roofs are good for

tropical conditions.

DIRECTIONS:

Study the given plan and make the sketches and visit a rearing house.

STUDY OF SERICULTURE EQUIPMENTS

Shelf rearing method requires the following equipment

1. Rearing stands

These are the frames used to accommodate the trays in which worms are kept

during rearing. This may be made of wood or bamboo or iron. The size depends upon the

trays.

2. Rearing trays

They are the portable receptacles for keeping worms during rearing. They vary in

shape and ·size. The commonly used rectangular trays measure 3.5' x 2.5'. The diameter

of the circular trays generally used is 3.5' to 4'.

3. Nets

Cotton or nylon nets are used for cleaning the rearing beds. The net is spread over

the worms over which the chopped leaves are spread. The worms move up from the old

bed through the meshes and reach the freshly supplied food. At this stage the net along

with the worm is transferred to another tray.

4. Cocoon age (Chandrikas of Montages)

These are meant to enable the ripe worms to spin cocoons. It is a rectangular

bamboo mat on which is fixed a spiral of bamboo tape, is fixed which forms the edges

for the women to spin the cocoons.

5. Dry and wet bulb thermometers

These are helpful in recording the room temperature and humidity during the

rearing period Hygrometer can be also used to record humidity.

6. Maximum and minimum thermometer

This helps in recording the maximum and minimum temperature of the rearing

room.

7. Room beaters

These are used in raising the room temperature whenever the temperature falls

below normal.

8. Miscellaneous requirements

Wax coated paper feather. chopping board. chopping knife, leaf preserving

baskets, preserving chamber, ant wells, sand beds. foam rubber, feeding stands, nylon

mesh.

DIRECTIONS:

Study the given equipment and make necessary sketches.

Ex No. 8 date

REARING TECHNOLOGY OF SILKWORMS

The practice of keeping silk worm eggs under managed environmental condition

for matching at the desired length of time and hour is called incubation.

The purpose of egg incubation is to achieve uniform hatching on a desired day by

keeping the eggs at and optimum temperature of 25°c and RH of 75-80 % in a room

already disinfected with 2% formalin thoroughly.

Multivoltine eggs can be incubated after surface sterilization with 2% formalin.

Univoltine and Bivoltine eggs when acid treated are to be surface sterilized before

incubation.

Multivoltine eggs are incubated at fanners rearing houses by placing the egg cards

between two sheets of paraffin paper kept in tray and a moist foam rubber strip is placed

around the eggs when prevailing humidity is low.

Eggs that have already turned blue (9 day old, eggs of Multivoltine / acid treated

eggs of other types are generally transferred into a (cardboard) 'black box! and kept

undisturbed for 24 hrs. Then the next day preferably during sunrise the eggs remove from

the .box and exposed to light The eggs tend to hatch out uniformity in development of the

growing embryos within the egg.

Brushing:

The newly hatched larvae are black and hairy commonly referred to as 'ants'.

Hatching is a photoperiodic response and begins with sunrise and continues till noon. The

process of separating 'ant' from the egg cards and transferring them to the rearing tray is

terms brushing' .The ideal time for brushing is 10.00 am as the peak of bathing would

have occurred.

Eggs are generally prepared on egg cards and the common methods adopted for

brushing are tapping method and net method.

1. Tapping / knocking off method or direct or feeding method:

This method is employed for brushing worms from eggs prepared on egg cards.

Freshly chopped tender mulberry leaf bits are sprinkled on egg cards with hatched out

worms. The worms occupy the leaf bits provided. After one hour the egg card is gently

inverted and the mulberry leaf along with the crawled worms will be made to fall on to

the wax paper spread in a tray. The worms still clinging on to eggshells can also be made

to fall on the tray by gently tapping at the back of inverted egg card. Then the bed is

prepared uniformly using chopsticks or white feather.

2. Net method:

This method is suitable for brushing loose eggs. The net is spread over the

hatched out worms and freshly chopped tender mulberry leaves are sprinkled over it

After half an hour, the net along with mulberry leaf bits and crawled larvae is gently

taken and spread in a tray , and the bed is made uniform using chopsticks.

3. Feeding:

Four times feeding/day is considered optimum. The quantity of leaf required for

50 DFS/a box containing 20,000 loose eggs in 550 to 600 Kg for Bivoltine and 350 to

400 eggs for multivoltine races. The leaf is either chopped/whole leaf is fed.

Stage Size of the Leaf

I 0.5 cm to 2 cm sq

II 2 cm to 4 cm sq

III 4 cm to 6 cm sq

IV Entire leaves

4. Cleaning: Often the worms are fed more than required. Hence cleaning is necessary

Instar No. of cleaning

I Once

II Twice

III Thrice

IV Daily

V Daily

CHAWKI AND LATE AGE MULBERRY SILKWORM REARING

TECHNIQUES

Brushing

The egg cards with worms are placed in the rearing trays or boxes and tender

mulberry leaves cut into small Squares (0.5 cm2) are sprinkled over the egg cards .the

Worms crawl on to the tender leaves and start feeding. Later the cards are tapped on to

the rearing bed. After Sometime the bed is uniformly prepared in the rearing trays and the

first feeding of mulberry leaves is given. Paraffin Paper is used as a bottom layer and as a

cover for rearing bed in the usual rearing trays.

Feeding silkworm

Care should be taken to feed the silkworms with sufficient quantity of leaves.

Otherwise it results in irregularity in the growth of worms. The first three instars feed

voraciously and leaves should be supplied accordingly. Entire leaf feeding Or twig

feeding is followed for the fourth and fifth instar Worm Four feeding (6.00 am to 11.00

am. 4.00 PM and 9.00 PM) are recommended where in more quantity of leaves should

be given at last feeding (900 PM) there is no necessity of covering the bed with paraffin

paper in fourth and fifth instars. Paraffin paper cover on the had should be taken out 30

minutes before Each feeding and also during molting in chawki rearing. Feeding Worms

should be stopped when the worm settle for moult and Started again when majority of the

worms come out from moult and started again when majority of the worms come out

from moult.

Bed cleaning

The accumulated old mulberry leaves, faceal matter. Exuvia, dead and unhealthy

worms should be removed periodically, usually the bed is cleaned once during first instar,

twice during second instar (just after first moult and again before settling for Moult).

three times during the third instar (just after second moult in the middle of the instar and

just before setting for third molt). And once day during fourth and fifth instars.

Spacing requirements for 50 laying (20,000 eggs)

Silkworm is a vary fast growing animal and records a 10.000 fold Increase in

weight and about 7000 fold increase in Size during the short period of 20-30 days.

Following is the spacing requirement for B mori

(Space in sq. mtrs)

For univoltine & Bivoltine

races

At the beginning each age At the end of each age

I Instar 0.2 1.0

II Instar 1.0 2.0

III Instar 2.0 5.0

IV Instar 5.0 10.0

V Instar 10.0 20.0

I

For multivoltine &

Bivoltine races in Tropical

areas

At the beginning each age At the end of each age

I Instar 0.2 0.5

II Instar 0.5 1.5

III Instar 1.5 3.0

IV Instar 3.0 9.0

V Instar 9.0 18.0

As the age advances the size of the bed should be increased at

the time bed cleaning .

Mounting

Transferring of ripe worms to suitable substrate (mountage or chandrika) for

spinning creating optimum conditions such as humidity (65-70%) temperature (24-25°C).

The mounting along with the mounted worms are placed in verandah or in open place

under the trees in a plant position immediately after mounting to facilitate dropping of the

liquid excreta on to the ground and to avoid staining of the cocoons.

During rainy seasons the mountages are places in well ventilated room with

gunny cloth spread on the floor to facilitate the absorption of urine and they are

periodically replaced to maintain dry condition during mounting.

The worm starts spinning Immediately and complete spinning approximately in a

day (24 hrs) later the worm transforms into pre-pupa and remams In this condition for 24

to 48 hrs-and the transforms to pupa 10 48 to 72 hrs

Harvesting of cocoons

In case of multivoltine races the optimum time of harvesting is 16th day after mounting.

while 10 Bivoltine it is 7th day after mounting. The cocoons are harvested manually by

hand and are sorted into good and defective cocoons. later the cocoons arc cleared by

separating the leaf bits, sticks and other extraneous materials for improving the quality

thus enabling to get higher price in the markets. Cocoons will be graded based on their

size, shape and compactness into different grades, viz., A, B, C etc.

Silkworm rearing index card

Log sheet no ______________Date of egg laying ___________

Bed no ______________Date of treatment ___________

Race ______________Date of brushing ___________

Procured form______________No. of eggs! laying ___________

No. of unhatched eggs__________

~-._--_._._._. __ ._-_ ... _-.- ---

8 Day l~ _

Date ofmounting: ._____ Date ofharvesting: _

Total cocoon yield. a) weight: __ ._ Kg b) Number: _

No of superior cocoons. . __ . __ . _

'\0 oflOfenor cocoons a) Thin ends: b) Stained: , _

c) \1clted: d) Others:_~ _

'\0 of double cocoons . _

./

i~ F (".A", f\ ," f~ ,no (.{ /)-;11[' i:..~ -h t1 (/7jx' (Aj 0 I (fJ J' :

IDENTIFICATION OF MOULTING LARVAE/RIPEWORMS:

All the species of silkworms have four stages in their life cycle namely, egg, larva pupa

and moth. During life process called moulting. Moulting duration ranges from 20 to 36

hours. Worms during moulting stages should be handled with utmost care.

1. Characteristics of moulting larvae:

Moulting is the process of shedding of old skin.

A. Larvae settling for moult (larvae preparing for moult)

1. Body becomes stout and shiny

2: Head appears small and dark in relation to its body size

3. Reduced feeding rate

4. Appearance of tight skin on the body

B Larvae in moulting :

I. Body becomes transparent with tight skin

2. Head is small

3. Feeding is completely stopped

4. No movement in worms. Sit at a place by raising head and thorax

5.Appearance of brownish triangular patch between head and prothorax

C. Larvae out of moult:

1. Larval body will have rusty colour

2. Head is pale brown and bigger than the previous instar

3. Worms become very active

4. Worms arc less shiny and have loose wrinkled skin

D. Ripe silkworms:

Silkworms attain maximum size after, 4th mouth seven day. Finally they stop feeding.

turn to pale yellow (local races), shinning and will moving restlessly in search of edges or

support for spinning, normally the ripe worms crawl towards corner of the trays or

periphery or edges of the trays. Such worms are to be picked and collected in plastic

bowls and transferred on to the suitable substrates for spinning. If they are not picked and

collected in plastic bowls and transferred on to the suitable substrates for spinning. If they

are not picked in time they start expelling the silk and spin a cocoon in the tray itself.

Ex No. 9 Date:

STUDY OF PEST AND DISEASES OF SILK WORM Bombyx mori L..

In addition to infection by several pathogens, the silkworm, Bombyx mori is also

infested by some insects and non insect pest, which contribute for cocoon crop loss.

1. Indian usifly : Exorista bombycis ( Diptera tachinidae)

It is commonly known as usifly. This is an endeparsite. These fly parasite

silkworms in chine, south Korea, Japan, India and Thailand. In India, it also

infests other commercially silkworms, namely Tara, Oak, Tasar, and muga.

In Karnataka, the infestation is maximum during rainy season followed by winter

and least during summer.

Life cycle : there are four distinct stages in the life cycle of this fly

1) egg: eggs are creamy white. 0.45 – 0.56 mm in length and 0.26-0.32 mm in

width. Oblong in shape and adhered on to the body. Incubation period is 24 to 36

hrs.

2) Maggot: Maggot passes three instar. It is fusiform in shape. Some what acute

anteriorly and rounded posterioly. The three instar are distinct in size

I instar 0.7 to 1.5 mm instar 2.75 mm

II instar 1.3 to 1.6mm

Yellowish white in I and II instars and creamy white in III instar maggot period is about 6

days.

3) Pupa puparium is oblong, bareel shaped, some what oval anteriorly and rounded

peosterioly reddish brown to a dark reddish brown. Body 11 segmented and measures

0.9-1.2 cm is length and 0.4 -0.6 cm width pupal period is about 14-16 days.

4) Adult : Adult is blackish grey in colour male is longer in length then female. There are

four longitudinal black lines on the dorsal side of thorax. Lateral regions of abdomen are

covered with bristles, which are more dense in male than in female. Male can be

distinguish from female by the present of external geneitalia covered with brown hairs on

the ventral side of the abdominal tip. The mated female fly lays around 300 eggs.

Nature of damage : two to three eggs are laid on the body of silkworm preferably during

4th and 5th instar, the young maggot on hatching from egg bores its way into the body of

silkworm through integument as a result of which black scar is observed in that part of

the skin. The maggot feed on the tissues of the silkworm, especially the far bodies . the

fully grown maggot punctures the body of the larva or pupa comes out and pipates in

cracks and crevices, the uzi pierced cocoons will be unfit for reeling.

2. Dermestid beetles (coleopteran : dermiestidae )

The grubs of these beetles feed on stifled cocoons that are stored fro ling time,

holes are bored and pupae and silk are eaten.

Adults are small beetles with brown to black elytra and club shaped antennae.

They lay eggs on some living matter like stored or stifled cocoons the larvae are small,

fusifrom. The pupa are naked. The larvae and adults feed on freshly spun, stored or

stifled or stifled cocoons cut them and make unreelable.

3. The straw mite: Pyemotes ventricosus ( Arachinda : Acari pyamotidae)

This mite is an ectoparasite of power post beetle, rice borer etc., which is

accidentally transported to the rearing house along with bamboo and straw. While

rehacthing and attacks silkworms larvae.

The symptoms of the infestiaons are

1. The affected worms loose appetite and become inactive

2. Difficulty of green fluid and excretion of black fluid by worms

pulsation becomes slower an irregular and dies.

4. Ants componotus compressus Tapinoma S. ( Hymenoptera formicidae)

Ants pose a serious problem to silkworm in poorly maintain rearing houses. They

attack the silkworms in raring trays and also while spinning and kill them by way of

feeding. The pose problem in graninge too.

5. Earwig Labia arachidis ( Dermsotera lebiidae)

It is one of the grainage pest living in crevices and rim of trays. The adults earwig

is dark brown and smooth measuring 1.3 cm in length and 0.3 cm in width.

The adult earwigs hold the abdomen of moths with the help of mandibles and

pitch the same with the aid of forceps like cerci. As a result black scar developed on the

moth. The affected moths will die after some time.

6. Rat :House Rate : Rattus. House Mouse. Mus musculus

They are considered as potential pest in grainge . rearing room and filatures. Rate

have special attraction fro silkworms, pupa and egg which from highly platable and

proteinous food for them. Rats feed on grown up worms and spinning worms on

mountages ( leaving aside silk glands they eat the reaming part of the body. They also

cut the cocoons and feed on pupa and egg. They also damage the equipment in addition

to these squirrels, bids and lizards also cause considerable loss to silk worms.

Directions

Observe the given pest their stage and the damages specimens and make diagrams

DISEASES OF SILK WORMS

The silk worm, Bombyx mori is domesticated since time immemorial is prone to

the attack of a number of diseases. Among the disease pebrine, pgraserie, flacherie and

musardione are important.

1. Pebrine disease : ( Nosema bomovois) Microsporida: Nosematidae)

The microsporidiosis of the silkworm is popularly known as pebrine all over the

world. Doquatrigages ( 1960) gave the popular name pebrine to this disease

because of the characteristic infrction and appearance of the dark pepper like

spots on the body of the diseased silkworm larvae.

Symptoms : Infected larvae shoe black pepper – like spots all over integument.

Larvae become pale unequal in size and sluggish. Infected pupae are heavier ,

black spots are also seen. Cocoons are flimsy moths from diseases pupae are

deformed with small crumpled wings and distorted antennae. Egg laying is very

irregular,. Eggs adhere loosely to the substraturn and they are clumsy in nature.

2. Muscardine disease

The fungal pathogens causing disease in insects are called muscardione disease

depending upon the etiology and colour of the spores, different kinds of

muscadines of silkworm are identified. They are white muscardine green

muscardine, yellow muscardine, red muscardine, purplish muscardione and

aspergillosis.

A. White muscardine ( Beauveria bassiana )

SYMPTOMS: It is severe in winter and particularly on Bivoltine., diseased

worms show loss of appetite become inactive. On progress of disease moist

specks oily specks appear on different parts of the larva. Larva experience

diarrhea and vomition. Body losses its elasticity negative response to external

stimuli. After death, body becomes stiff and hard. White efflorescence emerges

out around spiracle and inter segmental areas. In about 1-2 days entire body is

covered with white specks becomes mummified.

B. Green Muscardine ( Metarrhizuman anisopliae)

Symptoms : During infestion worm loses its apetite becomes inactive, diseases

specks notices all round the body. On ecolalpese large specks are formed. after

death, gradually worm becomes stiff and hard in 2-3 days. Later the entire body is

covered with green mycelia which bears conidia.

C. Aspergillosis ( Aspergillus tamari)

The disease is very serious in Japan in chawki worms raced chawki rearing

centers as the conditions maintained for developed of worms is favorable to the

growth of fungi

SYMPTOMS: Infested young worms become compact to lustrous and dies soon.

Hardening of body infection is localized . after death mycelia emerge out.

Generally young worms body will not rot but in case of late age worms , the are

which is not covered by mycelia mill not die to secondary infection . if it is 1

tamarii initially it will be white greenish yellow, green and finally brown and dark

brown with large head like structure.

3. Flachetie

The term flacherie refers to flaccid condition of larvae suffering from dysentery.

It maybe due to virus or bacteria.

A Viral flacherie ( Cytoplasmic polyhedrosis virus Billisappe )

This virus infect cytoplasm of the cell. This exhibit various symptoms of

flacherie.

Symptoms Infected worm show stunted development leading toprolonged larval

period on progress midgut becomes opaque and pale yellow later discharge

whitish faces and soil the bed. The midgur is tubnied white. Which adbcaes from

posterior to anterior direction and polyhedra pass along with aces inservere state

chain excreta and rectal protrusion are also noticed.

b) Kenchu virus disease ( Kempusappe or kempanachu )

The particular disease occurs very frequently on early instar worms in Karnataka

SYMPTOMS : Dullness paleness, disproportionately large head in some cases,

retarded growth, chroncity, affected with convulsions die in a short period, dead

worms gradually turn to brown blackish and rot, foul smell is emitted by such

worms.

B. Bacterial Flacherie

a) Sotto disease ( bacillus thuringiensis Var Sotto )

The infected worms are killed bny the toxin produced by the organisms

SYMPTOMS Loss of appetite , inactive affected with convulsion die in a short

period. Dead worms gradually turn to brown, blackish and rot, foul smell is

emitted by such worms.

b) Rangi or court disease ( serratie marceacence)

This is a monir bacterial disease. The body of the infected worm appears red due

to the pigments produced by the bacterium.

4. Nuclear polyhedrosis ( Jaundice of silkworm )

In kannada it is commonly called “halu or haluthonde”

SYMPTOMS : about a week after infection intersegmetnal memebrance become

swollen and the larvae appears to be under stress. haemolymph becomes trunied,

skin lose tension, becomes fragile and rupture easily releasing the milky

haemolymph.

DIRECTIONS

1. Study the given diseased specimens of Bombyx Mori L with special references

to the symptoms and make necessary drawing.

Expt. No. Date

STUDY OF SILK WORM REELING AND VISIT TO MULBERRY GARDEN

REARING UNIT, COCOON MARKET, GRAINAGE AND REELING UNITS

The cocoons are judged by the actual tests

1. Shape cocoons described as spherical oval, spindle irregular and double irregular

and double

2. Size : Size is measured by number. The cocoon held in a kg of raw silk is counted.

3. Hardness : this is the dentist of the cocoon layer and is determined by feel and

elasticity of the cocoons.

4. Thickness : the shell of the cocoon should be uniformly thick at each part if cocoon

are not uniformly thick, they can not be uniformly cooked and reeling is affected and

filament o not unwind freely.

5. Structure of silk layer : The worm first spins loose fluff which looks like cotton and

subsequently cocoon layer is more regular. The cotton like appearance is termed floss.

The floss forms a distinct counter layer of the cocoon. It is well pronounced and heavy in

Multivoltine races.

6. Wrinkles : the first formed outer layer of the cocoons dries up to a greater extent

then the inner layers. Consequently the cocoon develops wrinkles/furrows on the outer

layer. The inner layer remains smooth.

7. Slime : S\ilk filament in a cocoon is described as slime or have weight of the cocoon.

Weight of the shell cocoon shall ratio are the other important parameters

Unwinding of the silk filaments from required number of cocoons and winding

them on to a reel is called silk reeling. The end product of silk is Raw silk

Raw silk is the compact, untwisted and under gummed silk formed by combing

required number of silk filaments from as many separate cocoons.

Steps in silk reeling

1. Purchase of reelable cocoons: cocoons have to be purchased from the cocoon markets

2. Preservation of cocoons

a stiffing of cocoons : Process of killing of pupa inside the cocoon without damaging the

cocoon shell.

b. Sorting of cocoons: The good reelable cocoons have to be sorted from the lot., the

defective cocoons viz. melted cocoons etc. are to be separated.

c. Storing of cocoons: good cocoons should be stored in rodent – proof well ventilated

storage structure. Cocoons have to be spread uniformly in thin layer on trays are stored

between the stands.

3. Cooking of cocoons : the reelable cocoons have to be cooked in boiling water for 3-5

minutes to soften the serion layer in the cocoon shell.

4. Brushing of the cocoons : After cooking the cocoons are subjected to constant stirring

by using a bamboo stick, broom stick of mechanical brush to remove the outer floss and

to trace the continuous filament.

5. Determining the size ( denier) of the filament : Denier is the expression of size

gravimetrically of 450 mts of the silk filament weight 0.05 gm then it is called as one

denier more conveniently 9000meters of silk filament forms one denier

Denier weight of the silk filament (g) x 9000 Length of the silk filament (m)

Two types of denier 1. Cocoon denier 2. Raw Silk Denier

Cocoon denier can be calculated by the above formula. Raw silk denier is predetemiend.

The international standards for eh raw silk are

1st category 18 denier and below ( fine )

2nd category 19 to 33 denier (Medium)

3rd category 34 denier and above ( coarse)

6. Formation of reeling end: the filaments from the required number of cocoons are

combined and passed though the jettaboutte of the threader and then passed through the

pore of the porcelain button. Later the filaments are inter twined ( croissure) to compact

raw silks later the thread is passed through the distributor and tied to the reel for reeling.

Types of reeling machines

1. Charaka - 4 ends traditional/improved

2. Domestic basin - 5 ends traditional

3. Cottage basin - 6 ends improved

4. Multi and filature basin 8-10 ends

5. automatic reeling machine

a. Constant number of cocoon maintainer type

b. Constant denier type

After reeling the raw silk is re-reeled to form a standard hank, then laced and

twisted to from a skeins ( 65-70 gm) are bundled to from a book. (2 kg) several books

are bundled to form a bale ( 60 kg).