How to Raise Silkworms? A Detailed Explanation of Silkworm Rearing Techniques, Methods and Management Key Points
In our country, silkworm rearing has a history of several thousand years. As early as ancient times, many people began to raise silkworms. This shows that the development prospects of silkworm rearing are very good; otherwise it would not have continued to the present day.
How to Raise Silkworms
Put them in a cardboard box, or a small rice-sifting basket; if using a sieve, put some paper in the bottom of the sieve as a lining.
When the young silkworms have just hatched from the eggs, you must be especially careful with them. Feed them relatively tender mulberry leaves. When changing the mulberry leaves, use a very soft brush to move them, and pay attention to the force used; sometimes the mulberry leaves are too dry, and if you are not careful, during the process of changing the mulberry leaves you will leave the young silkworms on the leaves to be discarded. They are a bit harder to raise when small, and once they grow bigger it is easier.
When they are about to spin cocoons, just take some wheat straw and tie it into a branched, twig-like shape.
After the cocoons break open, put them together in a box; they will mate together and then lay eggs. Sometimes, because few silkworms are raised, when the cocoons break open some moths will be left alone, but do not worry; as long as one pair of silkworms succeeds, believe me, that is enough for you to raise.
The mulberry leaves must be fresh. You can also collect one plastic bag at a time, use a few leaves each day in portions, and sprinkle a little water on the rest and store them in the refrigerator to keep them fresh. The collected leaves will have a certain amount of dust; they can be washed clean and then dried in the shade. They must be dried in the shade, otherwise if the young or large silkworms eat them they will get diarrhea, and they might even die.
Silkworm Rearing Techniques
1. Spraying mulberry leaves for supplementary feeding in silkworm rearing: add 5 milliliters of fermentation liquid to one jin of water, spray 10 jin of mulberry leaves for supplementary feeding, once a day. The silkworms love to eat, their droppings do not stink, they grow fast, the cocoons are thick and of good quality, and production can be increased by about 10%.
2. Spraying the silkworm body to cool them and relieve summer heat: in summer the temperature is high, silkworms are prone to illness, and if the room temperature is too high the silkworms are also prone to heatstroke and death. On high-temperature days, add 5 milliliters of fermentation liquid to one jin of clean water and spray it on the silkworm body, once each at midday and in the afternoon every day.
3. Spraying mulberry leaves to keep them fresh: in summer the temperature is high, and mulberry leaves collected and piled up for a long time will turn yellow and deteriorate; in autumn the climate is dry, and mulberry leaves collected and kept for a long time will dry out and harden. Add 5 milliliters of fermentation liquid to one jin of clean water, use it to moisten the mulberry leaves, then put the mulberry leaves into woven bags or pile them on the ground and cover them well with plastic sheeting; after 24 hours they will still be as fresh and green as at the beginning.
4. Spraying mulberry leaves to promote growth: add 1—2 milliliters of fermentation liquid to one jin of water, spray it on the mulberry leaves in the mulberry field, spraying 2—3 times a month; adding 0.2% potassium dihydrogen phosphate gives a better effect. It is best to spray until the mulberry leaves are completely wet but not dripping. The mulberry leaves grow fast, and the leaves are oily green, thick and plump, and production can be increased by 20—25%. It can also reduce pests and diseases.
Note: within 6 hours before and after using Huoli 99 fermentation liquid, antibiotics must not be used. No matter how long the fermentation liquid has been stored, as long as it still has a sweet, mellow qu aroma, it can be used; if it stinks, then it cannot be used.
What Should Be Noted When Raising Silkworms in Summer and Autumn
1. Prevent pesticide poisoning. During the silkworm rearing season, do not spray organic chlorine pesticides such as dimethoate in farmland near the silkworm room; their fumigant action will cause silkworm poisoning. Mulberry leaves fed to silkworms must be confirmed non-toxic through trial feeding before leaves can be collected to feed the silkworms.
2. Mosquito coils or mosquito-killing and insect-killing agents are prohibited in the silkworm room. If used in dwellings adjacent to the silkworm room, the doors and windows of the silkworm room must also be closed to prevent silkworm poisoning.
3. The silkworm room should be fitted with screen doors and screen windows to prevent flies from entering the silkworm room and harming the silkworms, and “silkworm fly killer” emulsion should be added or sprayed on the silkworm body to kill fly maggots.
4. Before raising silkworms, block rat holes. A certain distance should be maintained between the silkworm racks and the walls, and lime powder or silkworm medicine should be scattered around the legs of the silkworm racks to prevent rats from climbing up. For raising silkworms on the ground, do a good job of chemical rat control.
5. Summer and autumn silkworm rearing have relatively high temperatures, so doors and windows should be opened to strengthen indoor ventilation and air exchange. Spraying mulberry leaves with clean water and using an electric fan indoors to blow a gentle breeze are also helpful for lowering the indoor temperature.
6. Diseased silkworms found should be promptly cleared away and put into a disinfection basin containing bleaching powder solution or lime slurry. Diseased silkworms must not be used to feed livestock and poultry, so as to prevent the spread and diffusion of pathogens and contamination of the environment.
7. Silkworm droppings contain large amounts of pathogenic matter. Do not spread them out to dry around the silkworm room; they should be concentrated in the field for composting or put into a manure pit for composting, to prevent the spread of pathogens.
8. Summer and autumn have high temperatures, and pathogens multiply quickly. Pay attention to collecting leaves according to need, transporting leaves promptly, and storing leaves reasonably. The mulberry storage pool should be disinfected once each instar, and do not feed overnight mulberry leaves.
9. In hot and humid weather, avoid feeding wet leaves. Do not sprinkle water on stored mulberry leaves. Remove droppings frequently and scatter more fresh lime powder, dry rice straw and other materials to inhibit the breeding and multiplication of pathogens.
10. Outside the silkworm rearing season, do not store grain, bran and similar items in the silkworm room, so as to avoid dampness producing mites that will harm the silkworms during silkworm rearing.
What Tips Are There for Saving Mulberry Leaves in Silkworm Rearing
Under normal circumstances in silkworm rearing, every 1 kilogram of silkworm cocoons produced requires 15 kilograms of mulberry leaves. After adopting measures to save mulberry leaves, about 50 kilograms of mulberry leaves can be saved per sheet of silkworm eggs, while cocoon yield and quality can be completely unaffected. The measures for saving mulberry leaves are:
1. Mulberry leaves should be reasonably collected, transported and stored. As much as possible, collect leaves in the morning or evening, collect and transport them promptly, and transport them loosely packed and quickly. After collecting the mulberry leaves, loosen them and put them into a mulberry storage pool or mulberry storage room, and store them reasonably to prevent wind damage or heat buildup from piling that causes deterioration and waste of mulberry leaves.
2. Prevent mulberry leaves from wilting. During the young silkworm stage, use heated bed (room) rearing and plastic film mulching rearing to help keep warmth and moisture and keep the mulberry leaves fresh. During the large silkworm stage, after feeding the silkworms, appropriately close doors and windows, and wait until the silkworms have eaten about 70% of the mulberry leaves before opening doors and windows for ventilation; this can effectively prevent mulberry leaves from wilting.
3. Ensure the silkworm room temperature. The suitable temperatures for large and small silkworms are 24°C and 25°C respectively. Within the suitable temperature range, the silkworms have a strong appetite, reducing leftover and poor-quality mulberry leaves, and also increasing the leaf-to-silk conversion rate.
4. Promote few-feeding rearing and whole-branch mulberry rearing. Labor-saving silkworm rearing techniques such as flat-and-three-dimensional once-a-day rearing for young silkworms, two-feed rearing throughout all instars, and whole-branch mulberry rearing for large silkworms not only improve silkworm rearing efficiency, but also help the silkworms eat mulberry leaves, saving about 5% of mulberry leaves compared with ordinary rearing.
5. Planned mulberry use and quantitative mulberry feeding. Formulate standard mulberry amounts for each instar, each day and each feeding according to the different silkworm stages, so as to achieve “silkworms eat their fill without waste, saving mulberry leaves without starving the silkworms.” At the beginning and end of each instar, the silkworms eat less mulberry, so leaf feeding should be appropriate. During the peak feeding period of the 5th instar silkworms, let the silkworms eat their full, but the maximum daily mulberry amount should be controlled within 110 kilograms.
6. Supplementary feeding of molting hormone. When about 5% of the silkworms show maturity, use 1 vial of molting hormone per sheet of eggs, dilute with 25 kilograms of water, mix with 20 kilograms of mulberry leaves, and let the silkworms finish eating it in one feeding; this can prompt the silkworms to mature all together, and about 10 kilograms of mulberry leaves can be saved per sheet of eggs.
How to Grasp Several Key Technical Links in Handling Molting and Waking
Handling molting and waking is a very important silkworm rearing technique. Whether it is handled well or poorly affects the health status and disease incidence of the silkworms, as well as the amount of cocoons produced. Therefore, the following technical links should be focused on:
1. Timely molting removal. Young silkworms develop quickly, fall asleep quickly, and have short molting periods, so the molting net should be placed earlier; fourth-instar silkworms have a long hypnotic period, so the net should be placed a bit later. In high temperature and high humidity it should be earlier, and in low temperature and dryness it should be later; falling asleep in the morning should be earlier, and falling asleep in the afternoon should be later. During molting removal, when a small number (2-3) of sleeping silkworms are seen in the rearing bed, scatter bran ash or fresh lime powder (to make the silkworms quickly crawl up), then add the molting net and feed mulberry leaves (mulberry leaves suitably mature but slightly tender); after all the silkworms have crawled up, it can be carried out. If the molting net is added at night, molting removal should be carried out after feeding mulberry leaves once the next morning.
2. Pick out the green ones and divide into batches. After molting removal, feed two mouthfuls of mulberry leaves; if all the silkworms have settled into sleep, there is no need to pick out the green ones, and the very few weak, small, late-sleeping silkworms in the bed should be picked out by hand and eliminated. If half have not entered sleep, use the central batch-dividing method to divide the silkworms into two batches for sleeping. The method is: when half of the silkworms are asleep, add another molting net and feed mulberry leaves evenly, so that after the silkworms crawl onto the net they are moved to an added nest for rearing and sleeping. If the silkworms' growth and development are uneven, use the method of picking out the center and dividing the two ends, separate out the large batch of silkworms in the sleeping state, and merge the early-sleeping and late-sleeping silkworms into one bed for rearing at the time of feeding after waking.
3. Management during sleep. After the silkworms enter sleep, keep things quiet, ventilate and exchange air, and prevent direct sunlight. In high temperature and high humidity weather, scatter bran ash or lime powder on the rearing bed to absorb moisture, which both prevents the breeding of pathogens and prevents early-waking silkworms from eating leftover mulberry and causing uneven development.
4. Timely feeding after waking: the principle of late feeding after waking should be implemented, that is, feeding after waking is carried out when the silkworms have basically finished molting and 80-90% of the waking silkworms' heads are light brown. In high temperature and muggy weather or during white rain, feeding after waking should be earlier. Generally, feed after waking 5-7 hours after the silkworms are seen waking. Before feeding after waking at each instar, disinfect the silkworm body and rearing bed, then place the net and feed mulberry leaves; the mulberry used should be fresh and slightly tender.
5. Control daytime molting. To control daytime molting, focus on the third and fourth molts. Generally speaking, if the third molt is daytime molting, the big molt will also be daytime molting; if the third molt is night molting, the big molt will also be night molting. With daytime-molting silkworms, the mature silkworms are ready at noon, and mounting on the cocooning frame is also convenient.
How to Carry Out Incubation and Collection of Newly Hatched Silkworms from Silkworm Eggs
Silkworm eggs should be placed in a ventilated bamboo cage or on a thread rack, and must never be wrapped with plastic film, cloth, newspaper or similar materials, to prevent suffocating the silkworm eggs. After receiving the eggs, immediately place them in a disinfected silkworm room for incubation protection. On days 1-4, keep the room at 22°C; from day 5 to the hatching period, keep it at 25°C. If the indoor temperature is low in spring, add a brazier to raise the temperature and keep it warm (use charcoal, do not use firewood), and keep the brazier more than 1 meter away from the silkworm eggs to avoid baking the silkworm eggs to death; when adding fire to raise the temperature, remember to add water to replenish moisture. By the 8th day of incubation, one end of the silkworm egg has a small black dot, called dot-blue.
When 20% of the egg grains in one sheet of silkworm eggs show dot-blue, wrap the silkworm eggs with newspaper, put the egg-bearing surface facing down, and carry out light blocking and blackening to make the silkworm eggs develop uniformly. From the day of dot-blue, the next day they turn blue (the egg surface appears gray), and on the third day the newly hatched silkworms emerge from the shells. At 5 a.m. on the day the silkworms emerge, remove the light-blocking material and turn on the light for exposure, to promote uniform hatching. If there are silkworm eggs that hatch late, continue light blocking and blackening, and carry out exposure and collection of newly hatched silkworms again at 5 a.m. the next morning. Finally, carry out collection of newly hatched silkworms. In spring, when the temperature is low, do it around 10 a.m.; in summer and autumn, do it around 8 a.m. The mulberry used for collecting newly hatched silkworms should be picked that morning, and the mulberry leaves selected should be suitably mature but slightly tender; the amount of mulberry used is 4-5 times the amount of newly hatched silkworms collected.
Method for collecting newly hatched silkworms: directly scatter the cut mulberry leaves onto the silkworm egg paper; after 10-15 minutes the newly hatched silkworms crawl onto the mulberry leaves, then pour the newly hatched silkworms together with the mulberry leaves onto the rearing bed paper, and use a goose feather to spread the newly hatched silkworms evenly. After collecting the newly hatched silkworms, when giving the second feeding of mulberry leaves, disinfect the newly hatched silkworm bodies, using “Disease Prevention No. 1” (a special medicine for disinfecting newly hatched silkworm bodies; for young silkworms use one containing 1.25% formaldehyde, and for large silkworms use one containing 2.5% formaldehyde). Put the medicinal powder in a gauze bag and evenly scatter it onto the silkworm bodies; a scattering amount like a thin layer of frost is enough. After 5 minutes, scatter a layer of burnt bran (rice husks burned black) to separate the medicinal powder, and then give the second feeding of mulberry leaves.
What Emergency Measures Should Be Taken After Silkworms Suffer Pesticide Poisoning
1. Quickly open doors and windows or carry the silkworms to a ventilated place, scatter sand-separating material, and add nets to remove droppings and give fresh mulberry leaves.
2. Quickly identify the source of the poison, cut off the source of the poison, and avoid poisoning again.
3. Detoxification treatment: for young silkworms, spray the body with clean water; for large silkworms, rinse them in clean water for two minutes, then scoop them out and dry them in the shade; some can revive, and feed them fresh leaves; all toxic utensils should be washed with alkaline water and then sun-dried. After organophosphorus poisoning, those that can still eat leaves may be appropriately given atropine as a supplementary feed.
4. For lightly poisoned silkworms and revived silkworms, strengthen nutrition, give suitably mature but slightly tender leaves, and adopt small-amount, many-feeding rearing. A small amount of sugar solution can also be given as a supplementary feed.
From the above analysis, it is not difficult to see that silkworm rearing has many techniques and skills. Therefore, raisers must constantly summarize and constantly innovate in order to develop steadily and consistently forward; otherwise, society is always progressing, and if one cannot keep pace with the times in a timely manner, one may be eliminated.