SSTL-Bangaluru

SILKWORM SEED TECHNOLOGICAL LABORATORY
How to measure and rectify alkalinity and acidity of soils?

Conduct soil test and based on the report, apply required quantity of gypsum to alkaline soils and lime to acidic soils.
How to control root knot disease?

An Integrated approach can contain the disease. Apply neem / pongamia oil cake @ 2 Mt / ha /yr in four split doses. Apply Bioneema, a bionematicide . (1 kg of bionema) with 24 kg neem oil cake and 200 kg FYM . Apply mixture of FYM and bioneema around root-zone and cover with soil followed by irrigation. In the case of severe attack apply nematicide, Sebufos @ 30kg/hac/yr in four split doses for effective control.
What are the reasons for occurrence of root rot disease and suggest control measures?

In the case of shoot rearing practices, shoots are frequently pruned and lichens grow on the shoots. This will be resulting in decaying of barks and stems to cause root rot. As soon as symptoms of sudden withering of leaves and drying / death of plants take place, uproot the infected plants and burn it. Remove the soil up to one foot from the infected spot. Dust the pit with 3-4 g Dithane M-45 and new sapling be planted after treating the root system with1 % Dithane M-45 solution. Besides, a biofungicide Raksha @ 1kg for 100 plants may be applied (mix 1 kg of Raksha with 50 kg of FYM,keep under shade for one week & then apply). Each plant may be applied with 500 g of the mixture in the root zone, but for new sapling, 500 g may be put in the pit and root of sapling should be treated with1 % Dithane M-45 solution for 30 minutes. After covering the root with soil, irrigation may be given.
What is the quantity of organic manure and chemical fertilizers required/plant / ha/yr?

There are 13888 plants/ha in Indo-Japanese method and NPK @ 350 : 140 : 140 kg in five equal doses in five mulberry crops may be applied for V1 variety. From this per plant can be calculated for one time application. Similarly 40 mt of FYM may be applied in two split doses.
What is the cost of mulberry production?

The average cost of seed crop mulberry garden maintenance/ acre/ crop accounts to approx. Rs. 8000. However, the cost may vary based on change in labour cost and other inputs.
Which variety of mulberry leaf is ideal for chawki rearing?

S36 mulberry variety is the most ideal for chawki rearing. However, V1 mulberry leaf with moisture content of 72-75% from the existing plot can also be utilized for chawki.
What is the suitable orientation for planting mulberry in row system?

Paired row Indo – Japanese system is recommended ( 90+ 150) x 60 cm and is widely practiced. However, depending upon the mechanization and resource availability, the farmers may adopt wider spacing of their convenience.
How to control Tukra disease?

Apply 0.2 % of DDVP in 0.5 % soap solution twice at an interval of 10 days with safe period of 17 days after spray.
How to apply Glycil for the control of weeds?

Glycil is a weedicide. Two sprays per year in alternate crops are recommended. Mix 7.1 ml glycel and 5 g Ammonium sulphate in one litre of water to prepare 0.2 % solution. About 200 litres solution is required for spraying one acre.
Whether practice of green manuring is useful?

Inter cropping with green manuring leguminous crop is useful for soil health and proper mulberry growth.
What is the method of vermicompost preparation?

The excreta of earthworm is called vermi-compost. It contains high nitrogen % besides micronutrients. Vermi compost is prepared by addition of earthworms in the semi decomposed FYM / farm waste kept in trenches. Use 1.5 kg earthworms (Eudrilus euginae, Eisenia fetida, Perionyx excavatus) per trench in 8 trenches [in a shed of 7.5 x 6 m] of dimension of 2.5 x 0.6 x 0.45 m for one hectare of mulberry plantation. To maintain 30-40 % moisture in trench, sprinkle water once in 2-3 days. Vermi compost is prepared within 6-7 weeks.
What is the leaf yield in the initial crops in complete organic farming system?

In the first two to three crops, there is a slight decrease in leaf yield, but it will not have any adverse affect on the quantity of leaf. In a course of 2 years, complete organic farming is possible provided proper recycling of farm waste, green manuring, vermin-composting and other microbial fertilizer application are done.
What is the suitable period to apply Bio-fertilizers and how much gap to be maintained for chemical fertilizer application?

The Bio-fertilizers are to be applied after one week of pruning and after about 10- 15 days gap, chemical fertilizers are to be applied.
In high compost application gardens, more pests are being observed, suggest the remedial methods.

DDVP takes care of many pests , hence it is more useful for controlling most of the pests in mulberry cultivation. Use DDVP 0.2% in 0.5% soap solution for Tukra and other pests. Remove and burn the infested shoots besides adopting the biological control measures.
What is the ideal method of shoot preservation?

Preserve the shoots loosely in upward direction, cover with wet gunny cloth and keep the room dark.
How can the quality of leaf be assessed?

The quality of mulberry leaf may be assessed by biochemical methods, however in field condition thick, shiny and glossy leaf with high green tint indicates superior quality.
What is the ideal stage of mulberry garden for late age rearing?

60-65 days old shoot for IV Instar and 65-70 days old shoot for V Instar is ideal.
What are the contributory factors for seed crop mulberry cultivation in V1 variety?

The NPK dose for V1 variety is 350 : 140 : 140 kg. All together there is 17 % increase in macro-nutritional requirement for V1 variety compared to K2 variety. Simultaneously there is 10-30 % contribution of micro-nutrition, 15-20 % of cultural operation and 10-15 % of plant protection measures.
How to control leaf roller problem in mulberry garden?

Foliar application of 0.076 % DDVP in 0.5 % soap solution to be done with 8 days of safe period. Release of egg parasitoid Trichogramma chilonis and pupal parasitoid Tetrastichus howardii can also control the pest.
How to prepare solution for plant protection?

D = A X B/ C, where D - Required quantity of chemical, A – Required quantity of solution, B- required % of solution and C – strength of the chemical or pesticide/ fungicide expressed in %
What is the effect of moisture variation in seed crop rearing?

Tender, medium and coarse leaves are recommended as per requirement of chawki and adult age rearing. Tender leaf may contain 76-79 %, medium - 74-75 % whereas coarse may contain apprx. 70 % moisture.
What is the role of micronutrients in seed crop mulberry cultivation?

Micronutrients play a major role in several metabolic activities responsible for protein, sugar and enzyme synthesis leading to proper quality mulberry leaf production. In the case of multiple deficiency of micronutrients, the yield may be reduced to even 50 %. By compensating deficient micronutrients, there is chance of 10-30 % compensation in leaf yield and up to 7 % in egg recovery / kg of seed cocoon.
What is the quantum requirement of bed disinfectant for application in different moults?

Apply bed disinfectant @ 3g /sq.ft during chawki and @ 5g/sq.ft during late age rearing. Further, apply the following quantity of bed disinfectant for 100 DFLs in different moults.
Moult Quantity (g)
After I moult 50
After II moult 150
After III moult 600
After IV moult 900
4th day of V instar 1900
How to use Bleaching powder solution for surface disinfection of sheet eggs?

Dipping the sheet eggs in formalin solution (2%) for 10 min. helps in complete surface disinfection. Whereas, 0.4% bleaching powder solution is recommended for the removal of gum and also surface disinfection of loose eggs.
What quantity of K2CO3 solution is to be added for testing of pupa, moth etc ?

1:9 ratio for pupa, 1:4 for moths and 10ml/g in the case of testing the litter.
What are the control measures for muscardine disease?

Provide sufficient aeration during late age rearing and bring down moisture level to 60~65%. 
Use ‘Resham Jyothi’ bed disinfectant as per recommendations or ‘Vijetha’ supplement or 2% Dithane M45 in Kaolin (3rd day of IV age and 2nd & 6th day of V age).
Dust slaked lime to shoot rearing bed and avoid feeding of tender leaf with high moisture.
Last two feedings can be reduced depending on appetite and feed the shoots placing in criscross condition which will facilitate better aeration.
What is the suitable embryonic stage for surface sterilization of eggs during incubation?

The eggs can be surface sterilized with 2% formalin at any stage except during pinhead and blue egg stages.
What is the importance of decol as general disinfectant?

Decol works as general disinfectant , as it is non - corrosive and eco friendly.
Up to 5th day in CSR breed, there was no disease, but how suddenly flacherie appears on the 6th day?

The infection has occurred 2-3 days before its symptoms. The pathogens are under incubation condition for 2-3 days. Disinfection and hygiene, temperature, humidity, aeration and spacing should be maintained properly besides providing nutritious leaf to the larvae.
What are the reasons for occurrence of diseases in final stage?

Improper temperature and humidity maintenance, lack of proper aeration and spacing for the rearing beds and inferior quality leaf feeding.
Can pebrinized male moths cause transovarian transmission in eggs?

Pebrinized male moths cannot cause transovarian transmission in eggs. Since, the spore size of Nosema bombycis is bigger, it cannot enter through the micropyle of the silkworm eggs.
What precautions are required to control incidence of grasserie.?

Take up effective disinfection and hygiene maintenance. Adopt recommended temperature of 24±1°C, humidity of 65% besides providing sufficient cross ventilation during late age rearing.
What is the simple method for assessing the chlorine content of Bleaching powder?

Titration method is the reliable method to assess the chlorine content of bleaching powder.
Whether liquid bleach for disinfection is advisable?

The disadvantage of liquid bleach is instability of the solution. Hence, usage of bleaching powder or Sanitol/Sanitech as disinfectants is more reliable.
What quantum of disinfectants have to be used per unit area?

Apply bed-disinfectants @ 3g / sq.ft. during chawki and @ 5g / sq.ft. during late age rearing.
How to use Dithane-M45 for the control of muscardine?

Dust 2% Dithane-M45 with Kaolin base for the control of muscardine disease. All the care should be taken in the preparation of the mixture as the higher percentage / improper preparation is deleterious to the silkworms.
Can different bed disinfectants be used alternatively during rearing?

Use only one type of bed disinfectant throughout the rearing instead of using different types.
Whether lime powder made out of lime stone at rearers’ level is good or ready made lime sold in market is good for bed drying?

Preparation of lime powder with lime stone is cheaper, but proper pulverization to be done with correct mesh size (200~250).
What are the main reasons for getting diseases in the late instar larvae?

Diseases occur because of bacterial/viral infection to the larvae. Hence, thorough disinfection has to be conducted before rearing and maintain hygiene throughout the rearing period, besides using the bed disinfectants as per the recommendations.
How to control muscardine in cocoon/pupa stage?

Use lime and reduce the bed humidity during rearing and keep the bed thin to avoid the incidence of muscardine. If the lots are affected with muscardine, it is not appropriate to procure such lots for laying preparation.
What are the critical aspects of pebrine control ?

Mother moth examination should be a must, besides, testing egg, larvae, and pupae. Litter examination can also be conducted.
What is the optimum cocoon weight to get good laying recovery ?

620 ~ 640 cocoons/kg (1.60 ~ 1.56 g) in the case of bivoltine and 900 ~ 1000/kg (1.1 ~ 1.0 g) in the case of Pure Mysore are ideal to get good laying recovery.
What are the reasons for the occurrence of trimoulters?

The reasons for occurrence of trimoulters are incubation of layings continuously under darkness or light, exposure of III & IV Instar larvae to high temperature (>30°C) and high humidity (>90%).
How many layings can be black boxed in a unit area?

About 5-6 sheets (100 dfls) can be safely black boxed in 2’x 2’ black cover.
Why leaf consumption is high in the PM race?

Increase in the fecundity, survivability, growth and development of larvae are the main reasons for high consumption. However, 10% feed cut in V Instar will not affect cocoon yield.
What is the ideal bed spacing required to rear 100 dfls in V age?

The ideal bed spacing required for 100 dlfs (40,000 larvae) is 600-700 sq. ft. for V age larvae i.e., 70 worms / sq. ft.
Whether tender leaf should be removed during shoot feeding?

Adopt shoot feeding by placing shoots in opposite direction and avoid exposure of larvae to tender leaf. Ensure that moisture content in tender leaf should not exceed 75% during late age rearing.
What are the reasons for small sized larvae on 2nd day of V age noticed in CSR2?

Resume the batch to V age after all the worms come out of IV moult. If a few worms have not shed the mouth parts completely, such small sized worms may be removed. Provide sufficient bed spacing.
Whether bed cleaning is necessary in shoot rearing system?

Yes. Clean the beds by using rope especially during humid conditions in order to keep the bed thin and dry. If possible, the bed can be cleaned once after IV moult. Otherwise, care to be taken to dry the beds properly and rearing can be continued as such without any cleaning.
Whether shoot rearing practices can be adopted for Pure Mysore?

Shoot rearing of Pure Mysore can be conducted and resort to picking of ripened worms before mounting for spinning.
Why do crops fail during hailstorms?


Sudden fluctuations in environmental conditions, high pathogen multiplication and feeding poor quality leaf are the main reasons for crop failures.
What are the reasons for occurrence of unequal worms in silkworm rearing?

Improper chawki rearing care especially care for resuming worms from each instar, crowding of worms due to insufficient bed spacing and non-maintenance of optimum temperature and humidity are the reasons for occurrence of unequal worms.
What are the ideal conditions for chawki rearing?

27~28 °C temperature and 80~90 % humidity are the ideal conditions for chawki rearing.
What is the ideal condition for spinning?

Temp. of 24~25°C and 65~70 % humidity is ideal during spinning.
When to harvest the seed cocoons?

The seed cocoons are to be harvested on 7th/8th day of spinning after ascertaining the proper development of the pupae.
How many hours can be delayed for resumption under unavoidable conditions?

Up to 4 hours delay in resumption will not have any bad affect on the rearing and grainage performance. Prolonged delay will certainly affect the health of the larvae.
How to control the non - hibernation in CSR4?

The main reason for getting non - hibernated eggs in CSR4 layings is high temperature during late age rearing. By providing optimum temp. of 24-26°C during late age rearing and spinning, the occurrence of non-hibernated eggs can be minimized. Also follow the photo period of 10h : 14h (L : D) during seed cocoon/pupa preservation to minimize the incidence of non hibernating eggs.
How to control the unfertilized eggs in CSR breeds.

The main reason for unfertilized eggs is high temperature during late age rearing and spinning.
Whether top clipping of tender leaf should be practiced before feeding?

In shoot rearing method, top clipping of tender leaf need not be adopted. However, if high moisture content is noticed during rainy season, too tender leaf can be removed. Place the shoots in opposite direction during each feed so as to expose the larvae uniformly to different stages of leaf.
Whether chawki rearing refers to II or III instar?

Chawki rearing is up to II moult. If chawki reared worms are supplied to the seed farmers after II moult, the farmers should adopt chawki rearing technologies during III instar also before taking up late age rearing.
Is it advisable to follow wrap-up method of chawki rearing during high humid conditions?

Ensure required humidity inside chawki rearing room. Avoid wrapping of paraffin paper sheets during high humid conditions. Care should be taken particularly during II instar by regulating feed and providing proper spacing.
What is the correct age and time for chawki worms transportation ?

Chawki worms can be transported in cooler hours when the worms are in second moult.
What are the critical points of management during moulting and spinning?

Apply lime powder when the larvae stop eating. Sufficient space should be given and allow the bed to completely dry, 25 oC temperature and 70 % humidity are required during spinning. Avoid self mounting during high humidity conditions.
What are the reasons for crop success in July-Oct for CSR2 and for CSR4 in Oct-Jan ?

All crops will be successful if the recommended packages of practices are followed.
What are the reasons for unequals in CSR crop, but no disease observed in microscopic examination ?

The non-maintenance of optimum humidity and temperature during chawki rearing, the resuming of larvae before all the worms are out of moult, inadequate spacing and inferior leaf quality are the major reasons.
How to control the hibernation in CB layings?

The main reason for occurrence of hibernated eggs in CB layings is due to the low temperature during late age rearing of Pure Mysore. By providing optimum temp. of 24-25°C during late age rearing and spinning, the occurrence of hibernated eggs can be minimized.
Is it advisable to allow the moths for 48 h oviposition?

It is always better to maintain the optimum conditions in the oviposition room and allow the moths only for 24 h oviposition. Since, 2 days oviposition will create some problem in uniform development and hatching, it is not advantageous. If required, the unlaid moths can be collected on the second day, paired once again and allowed for oviposition.
What are the reasons for getting pink colour in the cold stored CB layings?

When the eggs are cold stored before reaching the longest embryonic stage, light red / pink colour develops in the eggs. It is better to cold store the eggs at 36 hours after egg laying by considering 8 PM of the oviposition day as zero hour.
How the fluctuation of temperature in cold storage affects hatching?

Fluctuation of ±1°C will not affect the cold storage of eggs. If, the temperature raises to more than 7°C for longer duration, the embryonic growth occurs and it affects hatching.
How to maintain pairing efficiency in the male moths of CSR2?

Maintain 75-80% humidity during male moth preservation which helps in maintaining the potency of male moths.
Can CSR hybrid male moths be used in cross breed egg production?

Bivoltine hybrid males can be used for CB laying production during the scarcity of Pure races.
How to calculate the age of eggs for preservation in different seasons?

If the temp. and humidity are maintained in the oviposition room, 8 PM on the day of oviposition can be considered as zero hour to calculate the age of eggs. If the temp. is low the layings can be preserved 3-4 h later than the recommended time.
What is the ideal Photo period for seed cocoon preservation?

Ideal photoperiod is 10L: 14D.
How to maintain humidity in refrigerators during preservation of male moths?

Preserve male moths only in 7°C cold chambers. However, in the refrigerators humidity can be maintained by covering the male moth preservation frame with wet cloth or by keeping saline water.
What is the suitable technology for synchronization of moth emergence?

To procure the lots with suitable spun on dates for effective synchronization. However, if required the cocoons can be preserved at low temp. of 7-10°C just before emergence for 2-3 days in PM and up to 5 days in Bivoltines.
How long can Kolar gold layings be preserved to postpone hatching?

If the layings are cold stored at the age of 36 hours (stage 15) cold storage period can be extended upto 20 days.
For how many days can PM layings be preserved?

By following proper technology, PM layings can be preserved up to 10 days.
What is the ideal no. of cocoons / kg required for seed production?

For CSR breeds – 550 to 700 and for Pure Mysore – 900 to 1000 is the ideal no. of cocoons / kg.
For how many days cross breed layings can be preserved to postpone hatching?

If the layings are cold stored at the age of 44 hours (stage 17) cold storage period can be extended up to 50 days under double refrigeration.
What is the ideal embryonic stage and duration of preservation of Pure Mysore layings?

Stage 15 (longest embryonic stage) is the ideal stage and the layings can be preserved up to 20 days at 5°C.
What is the reason for occurrence of pink colored eggs in Pure Mysore ?

Preservation of eggs before stage 15 leads to occurrence of pink colored eggs in Pure Mysore.
What are the reasons for delayed hatching in pigmented eggs of Pure Mysore?

In pigmented eggs, the embryonic growth is slow up to blastokinesis stage which results in delayed hatching.
How to calculate ‘zero hour’ of embryo?

Under optimum conditions 6 pm on the day of oviposition will be the zero hour for CSR breeds, for CB it will be 8 pm.
What are the problems due to fluctuation of temperature in cold storages during layings preservation?

If the temp. reaches to 7-8°C, the embryonic growth starts, and if continued for longer duration, the embryonic stage is to be verified for further continuation of cold storage, otherwise leads to poor hatching.
What is the influence of light intensity on the oviposition?

Maintain complete darkness in the oviposition room. This helps in uniform egg laying.
What is suitable temperature and stage for preservation of CSR2 cocoons for synchronization?

One day prior to emergence, CSR2 cocoons can be preserved at 7.5 to 10°C for three days.
Whether seed cocoons with heavier weight are good for quality seed cocoon?

Heavier seed cocoons are not good for quality seed production.
Is there any adverse effect on eggs if egg sheets are dipped in 2% formalin for 10 minutes during surface sterilization?

No adverse effect. They should be dipped in 2% formalin for 10 minutes for proper surface sterilization.
What are the criteria for seed cocoon selection

The criteria for seed cocoon selection are high pupation rate, pebrine freeness and standard number of cocoons / kg.
What are the reasons for occurrence of unfertilized eggs?

High temperature and low relative humidity during cocooning, cocoon preservation and oviposition lead to occurrence of unfertilized eggs.
What are the precautionary measures for incubation?

Maintain required temperature, relative humidity and aeration to facilitate uniform development of embryo.
What is the safe interval between two pairings?

The safe interval between two pairings is 2 – 3 hours after giving rest to males at low temperature.
Whether eggs can be transported after 5th day?

Eggs can be transported safely under suitable temperature and relative humidity conditions.
What are the reasons for early hatching and late hatching?

Maintenance of optimum temperature and humidity during incubation results in better hatching at appropriate time.
Whether double cocoons can be used for seed preparation?

Yes, the double cocoons can be used for seed preparation.
What is the appropriate time for acid treatment for eggs?

Appropriate time for acid treatment of eggs is after 18 – 20 h from 0 hour.
Can we use CSR4 in place of CSR2 for CB production ?

It is not a designated combination, but can be used as a last resort.
How to get high fecundity?

Preserve cocoons at optimum conditions of temperature (23 – 25°C) and humidity 70 – 80% so as to obtain maximum emergence of moths (> 85%) with high vigour. This results in high fecundity.
How to reduce the incidence of dead eggs ?

Appropriate condition for cocooning, transportation and processing in grainages.
What are the critical stages of embryonic development for seed preservation ?

Stage 15 (longest embryonic stage) is the ideal stage and the layings can be preserved up to 20 days at 5°C.
Whether CSR2 race can be used for more than two matings?

Yes, CSR2 race can be used more than 2 times, if the cocoon quality is good.