Commercial Chawkie Rearing Centre - Seri.ap.gov.in

PROJECT MODELS - 2 & 3MODEL PROJECT FOR ESTABLISHINGCOMMERCIAL CHAWKI REARING CENTRE (CRC)IntroductionRearing of young age silkworms rearing up to 2nd moult is called as 'chawki rearing' whichusually lasts up to 10 days, and is a vital aspect of sericulture industry. Chawki rearingrequires technical skill which is quite often not available with the common sericulturists.Further, many sericulturists do not have the necessary equipment to rear the young agesilkworms under ideal conditions. These difficulties could be mitigated to a great extent, ifrearing of young age worms is conducted in Chawki Rearing Centres (CRCs). In CRCsrearing of young age larvae is conducted by trained technicians in a common place, which isprovided with the requisite equipment for maintaining the optimum temperature andhumidity. Mulberry leaf required for the young age worms is obtained from a wellmaintained garden so that quality of leaf is ensured. The worms are distributed to the farmerswhen they have settled for second moult or out of moult.Chawki worms, reared with care under ideal conditions and technical supervision of experts,tend to grow vigorous and healthy and give stable crops when shifted to the rearers' house.This system cuts down the cost and also the rearing period at individual farmers' houses andis proven to have better returns.The concept of chawki rearing is not new. In developed countries like Japan, China andKorea, chawki worms are supplied to the farmers in majority. For example, in Japan about95% of the worms are distributed only after chawki rearing. On the contrary in India, onlyabout 10% of the rearers receive chawki reared worms.Advantages of exclusive CRC Stabilisation of cocoon crop and increase in yield Improvement in quality of cocoons Control over disease spread Reduction in rearing expenditure Distribution of labour for other works1

Technology Package for Commercial Chawki RearingThe basic requirements for chawki rearing are a well maintained irrigated mulberry garden, asuitable rearing house with required appliances and well trained manpower. The CentralSericultural Research and Training Institute (CSRTI), Mysore developed specific package ofpractices, covering all aspects of commercial chawki rearing to make it economically viableand easily adaptable. The technology developed by the CSRTI is briefly outlined below:A. Establishment of Chawki Mulberry GardenOf the different factors responsible for healthy chawki rearing, leaf quality plays an importantrole. Moreover, the nutrient requirement of chawki worms is totally different (soft, succulentleaves rich in protein and carbohydrates) from that of late age worms (which require coarseleaves with less moisture, less carbohydrates but high protein). Since such specific qualityleaves are not produced from a general garden, especially the leaves contain very lessmoisture (less than 76%) and are poor in nutritional constituents, a separate mulberry gardenfor quality leaf production for young age silkworm rearing is imperative.The Technology Soil: The plantation of mulberry should be taken up in flat land with porous and fertilesoil. Sandy loam soil is preferred with good drainage. Variety : For new gardens, varieties like V-1 or S-36 should be selected. Spacing : Ideal spacing to be adopted is 90 cm x 90 cm or 60 cm x 120 cm. However, ifa CRC desires to adopt partial mechanisation of the garden, paired row planting adopting aspacing of (150 cm + 90 cm) x 60 cm is ideal. Training Schedule : after an establishment period of about one year, the plant should bepruned at crown (20 cm above ground level), during the onset of monsoon. After 35 days ofbottom pruning, harvesting of leaves may be commenced for next 7 days (up to the end of2nd moult). At the end of 10 days, the top terminal bud is clipped. Twenty five days aftertop clipping, second leaf harvesting as shootlets is to be done for rearing of worms up to 2ndmoult. Thereafter, the plants are again pruned at crown (80 days after first pruning). Thiscycle has to be repeated four times to get 8 crops in a year.2

Advantages of the Production TechnologyLeaf Yield : The above technology ensures a yield of 25 MT of chawki leaves/ha/year, asagainst 7 MT/ha/year of chawki leaves obtained from common garden through selectedharvesting. In this method, almost 100% of the leaves produced are suitable for chawkirearing.Leaf Quality : Qualitatively, the leaves produced by the above technology are superior(80% leaf moisture, 25% leaf protein and 13% leaf sugar) to the leaves obtained from thecommon garden (76% leaf moisture, 21% leaf protein and 11% leaf sugar).Rearing capacity : Annually, approximately 1,25,000 dfls per ha can be reared up to 2ndstage by adopting this package @ 20 kg chawki leaves /100 dfls against approximately40,000 dfls/ha/year from a general garden. Manure and Fertilizer Schedule Manures : The annual dose is 40 MT FYM per hectare, to be applied in two equal splitsin first and fifth crops (June and November). Fertilizers : The recommended chemical fertilizer dose is 260 : 140 : 140 kg NPK per haper year. It is to be applied in 8 equal splits after each harvest. Chemical fertilizers shouldpreferably applied in the form of ammonium sulphate, single super phosphate and muriate ofpotash. Irrigation : 3.75 ha cm of irrigation water is to be provided once in 4-5 days by ridgefurrows method (85000 gallons of water/ha each time). Leaf Harvest : Individual leaf plucking is recommended for 1st, 3rd, 5th and 7th crops,while the shootlets are to be harvested in 2nd, 4th, 6th and 8th crops for the purpose ofrearing. Pruning : Plants are to be pruned at the crown four times in a year after 2nd, 4th, 6thand 8th crops, matching the training schedule.3

B. Chawki Rearing Technology Disinfection and hygiene maintenance during chawki rearing : Early instars (1st -3rd) of silkworms are more susceptible to diseases compared to late instars. Bivoltine racesilkworms are more susceptible to diseases than multivoltine races. To prevent the diseases,it is necessary to maintain good sanitation and adopt hygienic rearing techniques. Handling of Silkworm Eggs (DFLs) : While transporting the eggs (DFLs) from thegrainage, the following precautions may be taken: Transport eggs during the cool hours of the day Avoid exposure to direct sunlight Avoid contact with chemicals, fertilizers and pesticides Avoid injury to eggs by physical shock Provide optimum temperature (25 o C) and ventilation to avoid suffocation of eggs.To meet all the above requirements, specially designed egg transportation bags may be used.These are made of two layers of nylon net with a foam sheet in between. Water should besprayed and the bag has to be made wet to meet the required temperature and humidity whiletransporting eggs. Surface Sterilisation of DFLs: In case of eggs in sheets, the sheets should be dipped in2% formalin solution for 10 minutes and wash them with clean running water and dry inshade. Incubation of Silkworm Eggs : The process of providing optimum temperature andhumidity to facilitate healthy growth and development of embryo is known as incubation.This should be done at incubation chambers or special facility attached in CRC itself. Forincubation of loose eggs, loose eggs incubation frames can be used. These frames are usefulfor incubation, black boxing and brushing of loose eggs. Black Boxing : The DFLs on reaching head pigmentation stage are wrapped with blackpaper / cloth to obtain uniform hatching of high percentage at a given time when exposed. Brushing : Eggs are brushed in CRCs. On the expected day of hatching, eggs areexposed to light at around 7.00 am for uniform and maximum hatching. Chopped mulberryleaves are sprinkled over the eggs sheets on the hatched larvae and after two hours when allthe larvae had crawled over the leaves, they are transferred to the rearing trays. In case of4

loose eggs before their exposure to light, two layers of mosquito net are spread over theeggs. Chopped leaves are sprinkled over the net and after about 30 minutes, the top net alongwith larvae is transferred to the rearing tray. Lower net helps in holding back the unhatchedeggs and empty egg shells.Characters of Chawki Larvae Resistant to high temperature, high humidity and badventilation Weak against pesticides and chemicals Disease resistance is very less Ingestion is less but digestion is more High growth rate. Out of the total leaf requirement, only 6% isconsumed during chawki stage, but the larvae grow 400 times inbody weight, 300 times in body size and 500 times in silk glandweight. Body water content is very low in the newly born larvae, butincreases rapidly till second instar. So, it requires high watercontent in mulberry leaves and high humid condition in rearinghouse. Chawki Rearing Methods:popular methods are stand rearing and chamber rearing.Chawki rearing can be done in different ways. The most Stand Rearing : Chawki larvae are reared in plastic rearing trays of 3' x 4' size. Thetrays are arranged in rearing stands. Paraffin paper is used as seat and cover. Box Rearing : Plastic trays are used for rearing. But the trays are arranged one abovethe other on a chawki rearing stand and put together thus looks like a box. This method helpsin maintaining the temperature and humidity. Rearing House : A separate rearing house wit adequate rearing space, sufficientventilation and light is essential. This will enable effective disinfection and also to maintainrequired humidity, temperature and other hygienic conditions. The rearing house to beconstructed away from the dwelling houses. Feeding : Mulberry leaves should be harvested during cool hours of the day andpreserved with wet gunny cloth to avoid leaf driage. Two-three feeds per day isrecommended. Leaves need to be chopped and fed to enable uniform feeding. The quantum5

of leaf required to feed 100 dfls is given in Tables 1 (for CSR bivoltine hybrids) and 2 (forCross Breeds). Spacing : As the larvae grow faster in size, they require more bed area. Usually, youngage rearing is conducted in crowded condition. The space required for rearing 100 dfls ineach instar is given in Tables 1 and 2. Bed cleaning : Left over leaf and litter accumulated in the rearing bed increases the bedhumidity and leads to multiplication of pathogens. Hence, periodic bed cleaning is necessary.However, cleaning during first instar is not recommended as it could increase the percentageof missing larvae. Cleaning is done twice during the second instar, i.e., once after resumptionfrom first moult and another before settling for second moult. Cleaning nets should be usedfor bed cleaning to avoid secondary contamination. Moulting care : When the larvae start settling for moult, the top paraffin paper isremoved, bed is spread and feeding is stopped. A thin layer of lime dusting (@ 3 g/sq.ft.)helps in drying of the beds, specially during rainy season. When more than 95% of the larvaeare out of moult, Vijetha, bed disinfectant (VETCARE) is dusted and after an hour feeding isresumed. Transportation of chawki larvae : Chawki warms are to be checked for occurrence ofdiseases before distributing to the farmers. Larvae are distributed to the farmers when theyare settled for second moult. Rearing bed is rolled and piled up in a tray and then transportedin a vehicle. Transportation should be done during cooler hours of the day, preferably duringevening.Plan for a CRC with a brushing capacity of 2500 DFLs per crop (32 crops/annum)Plans for brushing 32 crops per year with 2500 dfls of bivoltine races per crop and 3125 dflsof Cross Breed races are presented in PLAN - 1 and PLAN - 2, respectively. In both theplans, a mulberry area of 1.60 acres is required to meet the chawki leaf requirement.Indicative project cost and economics of these activities are presented in Modules 8 and 9,respectively. It may be seen that both these project modules are financially viable andbankable. The financial indicators of these modules are presented in the next page:6

Particulars Project Model-2 Project Model-3Production programmeBV races 2500 dfls/crop CB races 3125 dfls/cropNo. of crops /year 32 32Area under mulberry (ac) 1.6 1.6Total production capacity of dfls per year 80,000 100,000Project Outlay (Rs. lakh) 3.58 3.59Bank Loan 3.04 3.05IRR (%) 33 47Benefit Cost Ratio 1.12 1.22Net Present Worth at 15% DF (Rs. lakh) 2.28 4.22Repayment period9 years with 2 years 9 years with 2 years gracegraceTABLE - 1. Recommended amount of mulberry leaf and rearing bed space for100 dfls of CSR Bivoltine Hybrids (50,000 larvae approx.)Instar Day Leaf (kg) Space (sq. ft.)At the At the EndBeginning1 1.0 6 sq.ft. (one trayof 3’ x 4’) 830024 sq.ft. (twotrays of 3’ x 4’)Firstlarvae/ sq. ft. 2100 larvae/ sq. ft.2 1.53 2.04 0.5Total 5.0Second 1 5.0 24 sq.ft. (twotrays of 3’ x 4’)2100 larvae/ sq. ft.2 7.03 3.0Total 15.0Grand Total 20.060 sq.ft. (Fivetrays of 3’ x 4’)800 larvae/ sq. ft.TABLE - 2. Recommended amount of mulberry leaf and rearing bed space for100 dfls of Cross Breed Races (40,000 larvae approx.)Instar Day Leaf (kg) Space (sq. ft.)At the At the EndBeginning1 1.0 6 sq.ft. (one trayof 3’ x 4’) 666624 sq.ft. (twotrays of 3’ x 4’)Firstlarvae/ sq. ft. 1666 larvae/ sq. ft.2 1.23 1.54 0.3Total 4.07

Second 1 4.0 24 sq.ft. (twotrays of 3’ x 4’)1666 larvae/ sq. ft.2 5.03 3.0Total 12.0Grand Total 16.048 sq.ft. (Fivetrays of 3’ x 4’)800 larvae/ sq. ft.Plan for a Commercial Chawki Rearing CentreParticulars Project Model-2 Project Model-31. Race of silkworms2 No. of DFLs per batch3. No. of batches per annum4. No. of DFLs per annum5. Requirement of chawki leaf per 100 dfls6. Requirement of chawki leaf per crop7. Total requirement of chawki leaf per annum8. Variety of mulberry9. Yield of chawki leaf/ac/year10. Extent of mulberry area requiredBivoltine25003280,00020 kg500 kg16,000 kgV-1 or S-3610000 kg1.60 acCross Breeds3125321,00,00016 kg500 kg16,000 kgV-1 or S-3610000 kg1.60 ac11. Plan of Chawki Garden Management :The whole plot of 1.60 ac of mulberry can be sub-divided into 4 plots of 0.40 ac each,sufficient to rear 2500 dfls at a time for every 10 days. Thus, 32 crops can be realised peryear, as per the following harvesting schedule.Plot 10.40 acLeaf harvest : Crop Nos. 1,9,17,25Shootlet harvest : Crop Nos.5,13,21,29Plot 30.40 acLeaf harvest : Crop Nos. 3,11,19,27Shootlet harvest : Crop Nos.7,15,23,31Plot 20.40 acLeaf harvest : Crop Nos. 2,10,18,26Shootlet harvest : Crop Nos.6,14,22,30Plot 40.40 acLeaf harvest : Crop Nos. 4,12,20,28Shootlet harvest : Crop Nos.8,16,24,328

Labour requirement and calendar of events for rearing 250 dfls of chawki wormsDay No. ofActivitypersondaysrequired1 1 Transportation of eggs fromgrainage to CRC2 1 Black boxing of the eggs3 2 Preparation for brushing4 2 Brushing5 2 Rearing6 2 Rearing7 1 Moulting care8 3 Rearing 2nd age9 4 Rearing 2nd age10 3 Distribution of chawki worms,cleaning and washing11 3 Disinfection of CRC equipment andrearing houseTOTAL 249