How to rear summer and autumn silkworms? Key technical points explained

The key factors determining the success or failure of summer and autumn silkworm rearing are first leaf quality, climate and pests and diseases, followed by silkworm variety, silkworm rearing techniques and equipment conditions, etc. Therefore, to rear autumn silkworms well, one must carefully analyze the factors affecting summer and autumn silkworm production, grasp the key points, seize the timing, create conditions, and ensure stable and high yields of summer and autumn silkworms.

How to rear summer and autumn silkworms

1. Strict disinfection and disease prevention. The interval between silkworm rearing periods is short, pathogens are fresh and abundant and infection is easy, so the silkworm room, silkworm utensils and environmental hygiene should be thoroughly disinfected. Adopt the method of first spraying disinfectant, then cleaning and dismantling for washing; the spray dose must be sufficient and every surface must be sprayed. Strictly implement the "three disinfection guidelines" of "thorough disinfection before rearing, continued disinfection during rearing, immediate disinfection after rearing", and carry disinfection and disease prevention through the entire silkworm rearing process.

For pesticide application during summer and autumn silkworm rearing, information must be exchanged with leaf-picking households; mulberry leaves in pesticide-applied areas must be picked and test-fed only after the residual period, and only after proving non-toxic can leaves be picked for rearing. Summer and autumn silkworm rearing should prevent flies and rats to avoid losses.

2. Regulate the rearing room temperature. According to the different climatic characteristics of summer and autumn, adopt corresponding measures to regulate and improve the silkworm rearing environment. During the young silkworm stage, use plastic film covering for rearing, which can keep warmth and moisture and is conducive to healthy development of the silkworms. During the large silkworm stage, choose tall, spacious and well-ventilated houses for rearing to prevent stuffiness; trees should be planted around the silkworm house and a shade shed built to reduce radiation. In high temperature and stuffy heat, strengthen ventilation and air exchange; in high temperature and dryness, cool down and add moisture.

3. Strengthen mulberry leaf management. Strengthening fertilization and pest control for mulberry trees and promoting mulberry growth is the guarantee of a bumper summer and autumn silkworm harvest. During the young silkworm stage (instars 1-3), pick appropriately mature leaves with the standard of proper green color and soft feel. In particular, mulberry leaves for receiving newly hatched silkworms should be appropriately mature and slightly tender. Avoid leaves with insufficient sunlight, old leaves, withered leaves, diseased and pest-damaged leaves, and pesticide-contaminated mulberry leaves. In summer and autumn silkworm rearing, leaf picking should be done in the morning before the dew has dried or in the evening; absolutely do not pick leaves in the middle of the day (except on rainy days). Picked mulberry leaves should be picked and transported quickly to prevent water loss and wilting.

4. Strengthen rearing management.

First: when collecting and transporting silkworm eggs, note that the eggs must not be piled up or held over long periods, and contact with high temperatures should be avoided as much as possible; collecting and transporting eggs should be done in the morning and evening, and after bringing them back they should be spread out promptly to prevent piling, heating and damaging the eggs. Distribution of silkworm eggs should also be done in the morning and evening as much as possible. Silkworm eggs must not contact pesticides or any harmful gases to prevent poisoning of the eggs.

Second: during the young silkworm stage, use plastic film covering for rearing; the silkworms grow and develop quickly, so the rearing bed area should be expanded in advance to prevent crowding and starvation. Every day use 2% effective chlorine anti-stiffening powder or fresh lime powder to disinfect the silkworm bodies and rearing bed. At the time of molting and waking, use a 500-fold solution of "Candbing Yizhiling", "Miejunling" or "Kejunxing" for supplementary feeding; for young silkworm leaves, soak or spray with 0.3% effective chlorine "Yangcanhuan" water for disinfection, drain and dry before feeding to the silkworms.

Third: during the large silkworm stage, achieve the "three sparsities": that is, the silkworm racks in the silkworm room should be spaced sparsely, the silkworm trays on the racks should be placed sparsely, and the silkworms in the trays should be placed sparsely; this is conducive to ventilation and air exchange, lowers temperature, and can achieve full satiation. During the large silkworm stage, especially in high temperature and high humidity, remove silkworm droppings frequently to keep the rearing bed clean and dry. During the large silkworm stage, labor-saving silkworm rearing stands should be promoted. During the large silkworm stage, use a 300-fold solution of fly-killing tablets sprayed on silkworm bodies and a 500-fold solution for supplementary feeding to prevent damage by fly maggots. Fourth: strengthen management of mounting on cocooning frames. Vigorously promote automated mounting technology. The specific method is: when the silkworms develop uniformly and 5-10% mature silkworms are seen, for each sheet of silkworm eggs use 4-6 sticks of "Chuantuo" mixed evenly with 20-30 jin of mulberry leaves in cold boiled water (4-6 sticks mixed with 1-1.5 jin of water), feed the silkworms at 10-12 p.m., and give no more mulberry leaves afterward; at 10-12 a.m. the next day, scatter some rice straw on the rearing bed or lay silkworm nets, place plastic cocooning frames or square-grid cocooning frames and other mounting tools on top of the rearing bed, and let the mature silkworms mount automatically and spin cocoons. After mounting, strengthen ventilation and moisture removal in the mounting room (use an electric fan to remove moisture if conditions permit), keep the mounting room, mounting tools and environment dry, improve cocoon yield and quality, and ensure stable and high yields of summer and autumn silkworms.

What needs to be prepared before silkworm rearing  

1. Report the number of silkworm sheets  

New mulberry-growing households can report the number when the mulberry height is about 0.7 m; old households report the number for the first batch of spring and autumn silkworms when the mulberry height is about 0.5 m, and for other batches report the next batch number when collecting silkworms. 1 sheet of silkworms requires 450-500 kg of mulberry leaves, and it is about 25 days from reporting the number to receiving the silkworms.  

2. Silkworm room  

The silkworm room requires a level, clean floor, with convection windows front and back, and preferably ground-level windows. Doors and windows should be fitted with gauze netting to prevent flies, and ground-level windows fitted with wire mesh to prevent rats. Both greenhouses and cement houses are acceptable (in cold weather a cement house is best, in hot weather a greenhouse is best). Rearing 1 sheet of silkworms requires about 30 sq m of rearing area and 10 sq m of dedicated mulberry leaf room.  

3. Silkworm utensils and medicines  

For 1 sheet of silkworms, prepare the following silkworm utensils and medicines:  

① 15-20 silkworm winnowing baskets 0.8 m wide.  

② Four leaf-picking baskets, about 20 sq m of medicinal film.  

③ 2-3 pairs of slippers, placed separately in the silkworm room and the mulberry leaf room.  

④ Several red bricks, mainly to facilitate feeding silkworms during ground rearing; generally place 2 rows of bricks per room to make walking back and forth convenient.  

⑤ 2 buckets dedicated to silkworm room disinfection and 1 sprayer; buckets and sprayers that have held pesticides must never be used to disinfect the silkworm room.  

⑥ 260 square-grid winnowing baskets.  

⑦ About 60 kg of lime, sprinkled with a small amount of water to slake it 3 days before receiving the silkworms.  

4. Disinfection  

Disinfection is the prerequisite for preventing and controlling silkworm diseases and ensuring high yield and quality in silkworm rearing, and must be carried out carefully. The first disinfection should be completed within 1 week before receiving the silkworms. First thoroughly clean the silkworm room, mulberry leaf room and surrounding environment; silkworm utensils can be placed in sunlight to expose them, then disinfect the silkworm room and utensils. At present the best medicine is "Xiaoteling". The preparation method of "Xiaoteling" is: first crush the main agent, stir it with a small amount of water into a paste, then pour in 25 kg of water, afterward add the auxiliary agent and stir slightly, let it settle for 15 minutes and it is ready to use. Use a dedicated sprayer to disinfect the silkworm room and all silkworm utensils; disinfection must be comprehensive and thorough, and indoor walls and floors must be sprayed evenly and thoroughly; after spraying, close doors and windows and keep them moist for 1 hour. After the disinfectant dries completely, repeat the disinfection once according to the above method. Soaking films, shoes, silkworm utensils, etc. in the medicinal solution for disinfection is more effective. After disinfecting the silkworm room twice, open the doors and windows, and note that undisinfected things must not be placed into a disinfected silkworm room.  

Profit from silkworm rearing  

Mulberry silkworm cocoon rearing is divided into spring silkworms, summer silkworms and autumn silkworms; autumn silkworms are further divided into mid-autumn silkworms and late-autumn silkworms. Spring silkworms have the best quality, followed by autumn silkworms. Rearing varieties include Nongsang, Dazhonghua and others. The growth cycle of mulberry silkworm cocoons is limited by temperature; each year spring silkworm rearing begins around April 20, with 26-27 days as one growth cycle, summer pruning begins around May 20, and after the mulberry trees grow new leaves again, summer silkworm rearing begins around June 25, with 24-25 days as one growth cycle. Because the interval between mid-autumn silkworms and summer silkworms is short, and poor disinfection may affect growth and quality, mid-autumn silkworms are generally not reared; late-autumn silkworms generally begin rearing around September 5 and end in early October. For the summer silkworm season, due to factors such as temperature, environment and purchase prices, some rearing households choose to rear two seasons, spring and autumn silkworms, and some choose to rear three seasons of silkworms. From surveys it is learned that: one mulberry sapling costs 0.4 yuan, 1440 are planted per mu, with 7-8 years as one cycle, and the average annual investment in mulberry trees is 87.27 yuan/mu.  

The net profit per mu of mulberry silkworms is 7542.49 yuan, and the price of mulberry silkworms is 2817 yuan per 50 kg. Due to rising purchase prices, cocoon income has increased. In recent years, silk processing enterprises have grown rapidly, and the total output of silk processing and the total demand for raw material cocoons have risen substantially; in order to maintain normal production, silk processing enterprises have no choice but to jointly purchase raw materials even when raw material cocoon prices are high and profit margins are not large. 

From the above analysis we can see that silkworm rearing is an investment project with good market prospects, because China is a major silk country, China's silk market demand is very large, and China is also a major silk exporting country. But mastering silkworm rearing techniques is also very necessary.