chawki rearing presentation with detail information about chawki rearng.ppt

chawki rearing presentation with detail information about chawki rearing and it will give all information about chawkirearing Silkworms, particularly the young ones, need to be fed with fresh succulent
leaves. This is more so in the case of young larvae which feed on the surface as
it would be difficult to scrap the surface without succulence and softness. Higher
temperature and dry atmosphere cause withering faster. Therefore, the leaves
should be harvested during cooler hours of the day, i.e., either early in the morning
or late in the evening. The leaves plucked from the garden should be brought to
the rearing house in baskets covered with wet gunny cloth to maintain freshness.
Transported leaves are immediately preserved in suitable containers like leaf
preservation chamber and covered with gunny cloth to maintain its moisture contentChawki rearing starts after brushing of silkworms into the rearing trays. The tiny
worms which feed on the surface of the leaves should be able to reach the surface
of the leaf easier and speedier. To facilitate this, we provide them chopped leaves
of about 1cm2 size. Chopping of leaves also helps in loosening and spreading the
bed when the bed is required to be dried which helps in killing the pathogens on
the bed. As the worms grow in size, the size of the chopped leaves can be
increased. Silkworms are fed three to four times a day depending on the climate.
During rainy seasons with cooler climate, even two feedings would be sufficient
while in hot and dry climate, the number of feedings is higher. The current general
practice is three feedings per day (8.00 am, 2.00 pm and 8.00 pm). Around 20
kg of tender leaves are required for rearing 100 dfls of the first two instars of
larvae and quantum varies from breed to breed depending upon the size of the
worms and the fecundity. The ideal temperature and humidity are 28°C and
85-90% for the first instar and 27°C and 85% for the second. To prevent loss
of moisture from the leaves and maintain them fresh, the worms are maintained
on a paraffin paper in the rearing tray and after feeding, the bed is covered with
another sheet of paraffin paper and the edges of both sheets folded together and
this is called 'wrapping up' (Fig. 2.4). Wherever paraffin paper is not available,
polythene sheets of 400 guage thickness can be used.Before each feeding, the paraffin paper cover is removed and the bed gently Chawki Rearing
spread and the left-over leaf is allowed to dry. The fresh chopped leaves are then
fed and covered with paraffin paper again. The rearing trays after feeding are
usually piled up one above the other on small stand altogether looking like a box
and therefore called "Box method of Chawki rearing" (Fig. 2.5).
If the trays are kept in the rearing stand, it is known as 'stand rearing' (Fig. 2.6).
About 100 dfls of crossbreds require around 15 ft2 bed area at the end of 1st
instar and 45 ft2 at the end of second instar; and bivoltines require 24 ft2 and
65 ft2, resp

1. Chawki Rearing of Silkworm

2. 26-Apr-24 RDP, DDN (UK) 2
Importance of Chawki Rearing
•Disease tolerance is low.
•Susceptible to low temperature and
humidity.
•Growth and development is vigorous.
•Require leaf with high nutrients and
water content.
•Need more.

3. 3
•Toraisehealthyandrobustyoungsilkworm.
•Tostabilizecocooncropandtoincreaseyield.
•Toimprovecocoonquality.
•Tocontrolspreadofdiseases.
•Toreducelabour.
•Tominimizerearingexpenditure.
Objective

4. 4
Environmental Condition for Chawkirearing
•Temperature: 28 °C –27 °C [1
st
and 2
nd
instars].
•Humidity : 85% -90 % and 80% -85 % for 1
st
and 2
nd
instars respectively.
•Light :More light is necessary
•Air Flow : Cross Ventilation

5. 26-Apr-24 RDP, DDN (UK) 5
Requirements of CRC
•Rearing House
•Incubation facility
•Rearing Equipments
•Mulberry Garden
•Disinfectants
•Skilled man power

6. 6
Location of CRC
•Isolated from commercial rearing area
•Nearer to the farmers
•Closer to the mulberry garden
•Located in cooler area

7. 7
Facilities of CRC
•Incubation of eggs.
•Storage of mulberry leaf.
•Rearing of worms.
•Storage of equipments and rearing
materials.

8. Ground plan for Chawki Rearing House
8

9. 26-Apr-24 RDP, DDN (UK) 9
Features of Rearing House
•High roof to allow maintenance of cooler
tempeture.
•Hotter zones –False roofing / roof covered
with straw.
•Walls should be built with hollow bricks –to
provide insulation.
•Ventilation and windows to provide for
circulation of air.
•Varanda all round the Rearing House

10. 26-Apr-24 RDP, DDN (UK) 10
Rearing House

11. 11
Rearing house

12. 26-Apr-24 12
Rearing Equipments
•Equipments for incubation
•Rearing trays
•Rearing stands
•Leaf preservation chamber
•Bed cleaning nets
•Room heaters, sprayer, hygrometer,
max-min. thermometer etc.

13. 26-Apr-24 RDP, DDN (UK) 13
Rearingmaterials
•Paraffin paper
•Disinfectants
•Bed disinfectants

14. 26-Apr-24 RDP, DDN (UK) 14
Mulberry Garden
•Fertile land.
•Suitable Mulberry variety.
•Wider spacing –3’ x 3’
•Irrigation facility.
•Application of FYM and NPK

15. 26-Apr-24 RDP, DDN (UK) 15
Chawki Mulberry Garden

16. 16
Incubation
•Incubateeggsat25±1°Cand85%RH
foruniformgrowthanddevelopmentof
embryoandtogetgoodhatching.
•Bivoltineeggsareincubatedin16
hourslightand8hoursdark.

17. 26-Apr-24 RDP, DDN (UK) 17
Incubation of eggs

18. 18
Black Boxing
•Atheadpigmentationstage,eggsaresubjectedto
completedarknesssincethedevelopmentofthe
embryoisfasteranduniforminlightuptopinhead
stageanddarknessenhancesuniformdevelopment
frompinheadtoonsetofhatchingThisiscalledblack
boxingtechnique.
•Covertheeggswithcleanblackpaperorclothoneday
priortohatchingi.e.atblueeggstage.
•Removetheblackclothandexposetheeggstobright
lightonthedayofhatching,

19. 19
Blue egg stage

20. 20
Black boxing

21. 26-Apr-24 RDP, DDN (UK) 21
Exposure to light

22. 26-Apr-24 RDP, DDN (UK) 22
Hatched larvae

23. 23
Brushing
•Brushhatchedlarvaeinthemorning
hours.
•Cutmulberryleavestoabout1cm
2
size.
•Sprinklethemonhatchedlarvae.
•After30minutes,inverttheeggsheet
andtapgently.
•Makeasquarerearingbed.

24. 24
Leaf chopping

25. 25
Brushing

26. 26
Bed making

27. 26-Apr-24 RDP, DDN (UK) 27
Temperature and Humidity
•Maintain 28°C and 27°C
temperatureand85%and80%
humidityinIandIIstage.
•Useparaffinpapertomaintainthe
humidity.

28. 16 Feb., 16 CBT, PAMPORE 28
Light and Air
•Fresh air and light is necessary.
•Remove paraffin paper cover
before feeding to allow fresh air.

29. 26-Apr-24 RDP, DDN (UK) 29
Selection of mulberry leaf
•Leaf should be tender, succulent and rich in
water and nutrients.
•Select 1,2 and 3 number leaf after glossy leaf
and 4, 5 and 6 number leaf in a branch for 1
and 2 stage worms respectively.
•The leaf should contain -
Protein : 26-27 %, Carbohydrate : 11 % and
Moisture : 78% -80%

30. RDP, DDN (UK) 30
Selection of tender leaf

31. 26-Apr-24 RDP, DDN (UK) 31
Leaf harvesting

32. 26-Apr-24 RDP, DDN (UK) 32
Leaf preservation
•Harvest the leaf in cooler hours i.e. in
morning and evening.
•Transport harvested leaf immediately.
•Preserve in leaf chamber covered with wet
gunny cloth.
•Preservation should be less than 12 hours.

33. 33
Leaf preservation

34. 34
Feeding
•Chop leaves to the size of 0.5 –1.5
cm
2
and1.5 –4.0 cm
2
for I and II
instar.
•Feed 3 –4 times a day.
•About 16-20 kg. of leaf/ 100 DFLs
is required.

35. 26-Apr-24 RDP, DDN (UK) 35
Feeding of larvae

36. 26-Apr-24 RDP, DDN (UK) 36
Spacing
•Increasethebedsizeasperthegrowth
oflarvae
•Bedspaceof4.4–7.5sq.ft.for1
st
stage
and17.5–52.5sq.ft.for2
nd
stageis
requiredfor100dfls.

37. 37
Cleaning
•1
st
Instar –No bed cleaning.
2
nd
Instar –Two cleaning.
•Use cotton net for bed cleaning.

38. 26-Apr-24 RDP, DDN (UK) 38
Moulting care
•Do not disturb worms during
moulting when the larvae settle for
moult.
•Remove paraffin cover.
•Reduce bed thickness prior to
moulting.
•Dust lime powder.
•Ensure ventilation to dry the bed.

39. 26-Apr-24 RDP, DDN (UK) 39
Use of bed disinfectant
•Dusting of bed disinfectants is important to
avoid secondary contamination. The quantity
and schedule of dusting of different bed
disinfectants for 100 dfls is given as under:
Dosage RKO Vijetha Resham
Jyothi
After 1
st
moult
60 g 50 g 50 g
After 2
nd
moult
120 g 100 g 100 g

40. 40
Lime dusting

41. Requirement of chawki rearing up to 3
rd
stage:
Factor. 1
st
stage. 2
nd
stage.3
rd
age
Temperature. 27 –28°C 26-27°C. 25-26
0
C
RH %. 85-90. 80-85. 75-80
Qty. of leaf. (Kg.) 3.5 –4.0. 14.0 –16.045-50
Leaf size. (cms.) 0.5 –1.5 1.5 –4.0 Chopped
Bed area. (Sq ft.)
(At the beginning)
(At the end)
4.4
18.0.
18.0
55.0
55.0
125.0
Feeding period 3 -3.5 days2.5 -3.0 days3-3.5 days
Moulting period 22-24 hr. 18-20 hr.26 –32 hrs.
Mesh size of cleaning nets5 sq mm 10 sq mm 15 sq mm

42. Advantage of chawki rearing:
•Ensures quality cocoon crop.
•Healthy and disease free worms.
•Uniform and vigorous worms with a minimal loss
of larval population.
•Reduction in rearing expenditure and saves
labour.

43. Thank you