CATDOLL : CATDOLL: What are the tips for raising silkworms? (What do the tips for raising silkworms mean?)

1. Seven tips for raising autumn silkworms?

Before raising silkworms, the area around the silkworm room should be cleaned and garbage and weeds should be removed. The silkworm room should be washed with clean water, and the silkworm tools should be washed in the river and pond before being exposed to the sun. A layer of soil should be scraped off the silkworm room and filled with new soil. The silkworm room should be whitewashed with lime slurry, and the silkworm tools should be immersed in lime liquid for disinfection. After the cocoons are collected, the surrounding area should be disinfected to prevent the spread of the disease source and the spread of bacteria. In addition, during the silkworm raising process, sick silkworms and underdeveloped silkworms should be strictly eliminated.

2. Select improved varieties in batches and reasonably

Autumn silkworms are divided into three stages: early autumn, mid-autumn, and late autumn. The general requirement is: raise more early autumn silkworms, raise mid-autumn silkworms well, and raise late autumn silkworms according to the leaves. In some places, autumn silkworms are raised five or six times, with too many batches, the silkworm room uses the same silkworm tools, and large and small silkworms are mixed, which will cause poor disinfection and the spread of pathogens, resulting in outbreaks of silkworm diseases and very few cocoons. Therefore, the batches of autumn silkworms should be reasonable, and the interval between the previous and next batches should be about half a month.

To raise autumn silkworms well, you should pay attention to choosing summer and autumn varieties that are easy to raise and high-yielding. These varieties generally have strong vitality. In addition, you can also save spring silkworm seeds for autumn. Spring silkworm varieties such as Dongfei Jiaohuahe and Hecheng Jiao 754 are all excellent varieties.

3. Strengthen mulberry tree management

"If you want good mulberry trees, there should be no weeds in the mulberry fields." Mulberry fields should be loosened and weeded in time, and watered during droughts to ensure the growth of mulberry trees. Leaves should be picked properly. One sheet of autumn silkworm seeds requires 800-1000 kilograms of mulberry leaves. Do not pick too many leaves or "strip them all". Mulberry leaf picking, transportation, and storage should be done well to prevent the leaves from deteriorating. Generally, leaves are picked mainly in the morning, supplemented by leaves picked in the evening. Load less and transport faster, and store in a relatively cool and humid place to ensure the freshness of the mulberry leaves.

4. Raise silkworms well and lay a good foundation

As the saying goes, "Raising silkworms well is half the battle". When transporting silkworm seeds, three precautions must be taken: prevent heat, sun and rain, and toxic gases. The transported silkworm seeds should be placed in a room with a temperature of 25℃ and a relative humidity of 80%. If the temperature is high, sprinkle well water to cool them down. The harvesting of silkworms should be completed by 8 am. The harvesting should be done on the same day the silkworms are born and the silkworms are raised in batches. Do a good job of handling them during the dormancy period. Make sure they are well fed before dormancy, take good care of them during dormancy, and feed them well when they are picked up. Promote the co-rearing of silkworms. The small silkworm room should be away from the large silkworm room, so that they can be raised by a dedicated person with dedicated utensils and in a dedicated room.

5. Raise silkworms well to ensure a good harvest of cocoons

Silkworms eat a lot, so they need to be well fed. Silkworms are prone to silkworm diseases when the temperature is above 22℃ and the relative humidity is 90%. Therefore, attention should be paid to cooling and heat prevention, ventilation and air exchange. The silkworm beds should be placed sparsely, and well water can be sprinkled during high temperatures at noon. In hot weather, the silkworms should be moved outdoors at night to "cool down". The moisture in the silkworm body is mainly absorbed from mulberry leaves. In a hot and dry environment, adding water leaves to feed the silkworms will have a better effect.

6. Pay attention to the prevention and treatment of silkworm diseases

Common diseases of autumn silkworms include gastrointestinal purulent disease and hollow-headed softening disease. You can use "Disease Prevention No. 1" or fresh lime powder to disinfect the silkworm seats. To prevent and treat stiffness disease, you can use anti-stiffness powder. To prevent and treat fly maggot disease, you can use "silkworm fly killer" medicine to sprinkle mulberry leaves on silkworms or spray on silkworm bodies. To prevent and treat bacterial diseases, you can use 500 times chloramphenicol solution to spray on mulberry leaves and feed silkworms. Starting from the fourth instar, add food once or twice per instar.

2. What are the correct methods and techniques for raising silkworms?

Silkworm eggs: Silkworms reproduce by laying eggs. Silkworm eggs look like fine sesame seeds, about 1 mm wide and 0.5 mm thick. A female moth can lay 400-500 silkworm eggs, 1700-2000 silkworm eggs, weighing about 1 gram. The color of silkworm eggs is light yellow or yellow when they are just laid, and turns into light red bean color or red bean color after 1-2 days, and then turns into gray-green or purple after 3-4 days. It will no longer change, which is called fixed color. The outer layer of silkworm eggs is a hard eggshell, and inside is yolk and serosal membrane. The embryo in the fertilized egg continuously absorbs nutrients during the development process and gradually develops into an ant silkworm. It crawls out of the eggshell, and the eggshell becomes white or light yellow after it is empty.

Ant silkworm: When the silkworm hatches from the egg, its body is brown or reddish brown, very small, and has many fine hairs, which looks a bit like an ant, so it is called an ant silkworm. The ant silkworm is about 2 mm long and 0.5 mm wide. After it crawls out of the egg shell, it will eat mulberry leaves after 2 to 3 hours.

The sleeping nature of silkworms: Silkworms eat a lot of mulberry, so they grow very fast and their body color gradually fades. But their appetite gradually decreases or even completely stops eating. They spit out a small amount of silk, fix their abdomen and feet on the silkworm seat, raise their head and chest, and stop moving, as if they are asleep. This is called "sleeping". The sleeping silkworms may seem motionless on the outside, but they are preparing to shed their skin inside. After shedding the old skin, the silkworms enter a new age. From ant silkworms to spinning silk cocoons, they shed their skin four times in total. Having the sleep nature is one of the growth characteristics of silkworms. Sleep nature is a genetic trait of silkworms and is also affected by the environment. The silkworms currently raised in my country belong to the four-sleeping varieties.

Silkworm age: also known as age, which indicates the development stage of the silkworm. From the ant silkworm to the first molt is the first age; after waking up from sleep, it enters the second age; after molting again, it enters the third age; after the third molt, it enters the fourth age, and the fourth molt is also called the long sleep. After the long sleep, it enters the fifth age. The fifth-age silkworm grows very fast, with a body length of 6 to 7 cm and a weight of about 10,000 times the weight of the ant silkworm.

Mature silkworms: When silkworms reach the end of the fifth instar, they gradually show the characteristics of maturity: first, the feces they excrete change from hard to soft, and from dark green to leaf green; their appetite decreases, and the amount of food they eat decreases; the front digestive tract is empty, and the chest becomes transparent; then they stop eating completely, their bodies shorten, and their abdomens tend to be transparent; their head and chest are raised, they spit out silk threads from their mouths, and they swing left and right and up and down to find a place to build their cocoons. Such silkworms are called mature silkworms.

Cocooning during the adult stage: People put mature silkworms in special containers or on cocoons, and the silkworms will spin silk and make cocoons.

Cocooning can be divided into four processes: 1. The mature silkworms first spit out silk, which is bonded to the cocooning device, and then spit out silk to connect the surrounding cocoon branches to form a cocooning support, that is, a cocooning net. The cocooning net does not have a cocoon shape, but is just some soft and messy cocoon silk layers to serve as a support for cocooning. 2. After the silkworms make a cocooning net, they continue to spit out messy silk circles to thicken the inner layer of the cocoon net, and then spit out silk in an S-shaped manner, and the outline of the cocoon begins to appear, which is called a cocooning coat. The silk fibers of the cocoon coat are fine and brittle, arranged very irregularly, and have a high content of sericin. 3. After the cocoon coat is formed, the cocoon cavity gradually becomes smaller, and the front and rear ends of the silkworm body bend back to form a "C" shape. The silkworm continues to spit out cocoon silk, and the spinning method changes from S shape to ∞ shape, which begins the process of forming a cocoon layer. 4. When the silkworm's body is greatly reduced due to a large amount of silk spinning, the swing speed of the head and thorax slows down, and there is no certain rhythm. The spinning begins to appear messy, forming a loose and soft cocoon silk layer, called a pupa lining.

3. How do modern people raise silkworms?

How did ancient people raise silkworms?

I will answer 1 answer

Anonymous user 2013-11-30

The Development and Dissemination of Ancient Sericulture Science and Technology

China is the earliest country in the world to plant mulberry trees, raise silkworms, and weave silk. The ancient Chinese working people invented the technology of planting mulberry trees and raising silkworms. In the long-term production practice, it has been continuously developed and improved, and has been spread to various countries in the world. Raising silkworms to produce silk is one of the most significant examples of the great achievements made by the ancient Chinese people in developing and utilizing biological resources. This is an outstanding contribution of ancient China to the people of the world.

A long history

According to legend, sericulture and silk weaving were invented by Huangdi's wife Leizu. Of course, such a great invention as sericulture and silk weaving can only be the result of the broad masses of people's continuous accumulation of experience in long-term production practice, and it is definitely not the invention of any one individual. However, this legend shows that my country's sericulture production does have a very long history.

Chinese archaeologists found a batch of silk fabrics in bamboo baskets at the Qianshanyang Neolithic site in Wuxing, Zhejiang, including silk pieces, ribbons and threads. This shows that my country had a relatively developed silkworm and silk production at least 4,000 years ago. If we go back further, in 1926, archaeologists found a cut silk cocoon at the Xiyin Village Neolithic site in Xia County, Shanxi, which is older than the Qianshanyang site. This cocoon may have some connection with the silk production activities of our ancestors.

Silkworms originally lived wild on naturally growing mulberry trees and mainly ate mulberry leaves, so they were also called mulberry silkworms. Before silkworms were domesticated, our ancestors knew how to use wild cocoons to reel in silk. It is still difficult to determine when artificial silkworm breeding began. However, as early as the Yin and Zhou dynasties, my country's sericulture production had already developed greatly, which shows that artificial silkworm breeding began long before the Yin and Zhou dynasties.

We can see direct records of sericulture in ancient documents. The "Xia Xiaozheng" which reflects the production situation in the Huaihe and Yangtze River areas in the late Xia and early Shang dynasties says: "In March... mulberry trees were trimmed... and concubines and daughters began to raise silkworms." This means that in the third month of the Xia calendar (the fourth month of the lunar calendar), mulberry trees should be trimmed and women began to raise silkworms.

The oracle bone inscriptions of the Yin Dynasty not only contain words such as silkworm, mulberry, silk, and silk, but also some complete divinations related to silk production. According to the research of oracle bone scholar Hu Houxuan, some oracle inscriptions record that people had to go through nine divinations to check on silkworms. It can be seen that sericulture was a very important production business at that time. There are also records about the silkworm god and the sacrifice to the silkworm god in the oracle bone inscriptions. At that time, in order to raise silkworms well, people offered rich sacrifices such as cattle or sheep to the silkworm god.

Archaeologists have discovered lifelike jade silkworms in Yin tombs more than once. For example, jade silkworms from the Shang Dynasty were unearthed in Yin tombs in Anyang, Henan and Subutun, Shandong. Silkworms were also often found as decorative patterns on bronze vessels of the Shang Dynasty. All these show that silkworms occupied an important position in the minds of people at that time.

Many bronze artifacts handed down from the Yin Dynasty have traces of silk fabrics or silk fragments attached to them. According to research, some silk fabrics reflect that there was already quite advanced silk weaving technology at that time; and there are a lot of facts that show that silk fabrics were becoming more and more important in the social and economic life at that time, and had become an intermediate medium for the exchange of goods. To produce a large number of silk fabrics, only by developing artificial sericulture can sufficient silk raw materials be provided.

By the Zhou Dynasty, mulberry planting and silkworm breeding had flourished in vast areas of my country from north to south. Silk had become the main raw material for clothing for the ruling class at that time. Sericulture and silk weaving were the main production activities of women. There are many poems in the Book of Songs that mention silkworms and mulberry trees. For example, the Book of Songs·Binfeng·July: "The spring sun is shining, and the orioles are singing. Women hold the baskets and follow the birds to pick tender mulberry trees for the silkworms." It means: There is sunshine in spring, and the orioles are singing. Women carry baskets and walk on the path to pick tender mulberry trees for the silkworms. This vividly depicts the labor scene of women picking mulberry trees and raising silkworms at that time.

Mulberry trees were planted on a large scale in the Zhou Dynasty. In the Book of Songs, Wei Feng, Ten Mu, there is a line "Ten Mu, the mulberry pickers are leisurely", which means: Ten mu of mulberry gardens and green trees, the mulberry pickers are so leisurely. This shows that mulberry trees were planted in large areas during the Spring and Autumn Period, and a mulberry field was as large as ten mu. The mulberry trees planted at that time were probably shrubs and trees. We can still see the vivid image of ancient working women picking mulberry trees with baskets in the mulberry picking pictures on bronze vessels from the Warring States Period, and we can also see the two types of mulberry trees planted at that time, tree-like and shrub-like.

According to ancient books such as The Book of Songs, Zuo Zhuan, and Rites of Rites, silkworms were not only raised indoors, but also had special silkworm rooms and silkworm-raising equipment. These equipment included silkworm racks ("栚" or "锤"), silkworm foil ("曲"), etc. This shows that by the Yin and Zhou dynasties, my country had already developed a relatively mature set of mulberry planting and silkworm-raising technology.

Development of sericulture technology

1. Mulberry Tree Technology (by Long Zhijing)

In the "Guan Zi·Shan Quan Shu Pian" of the Warring States Period, it is said: "For those who are proficient in sericulture and can keep silkworms free from disease, one pound of gold and eight stone of food are given to them. Their words are carefully listened to and stored by the government, so that they have nothing to do with the army." This means that if there are people among the masses who are proficient in sericulture technology, can raise silkworms well, and keep silkworms free from disease, they will be invited to share their experience and be rewarded with gold and exemption from military service. Indeed, the most experienced and knowledgeable people are the broad masses of people engaged in production practice. Among them are many sericulture experts and masters. In their long-term silkworm production practice, they have continuously created and invented, and accumulated extremely rich and valuable experience for the silkworm industry in my country and the world.

There are many books about mulberry planting and silkworm breeding in ancient China. The Han Dynasty mentioned that there were sericulture works such as "Silkworm Law", "Silkworm Book", "Planting Trees, Hiding Fruits and Silkworms" in ancient my country. Unfortunately, these ancient books have been lost. However, since the Han Dynasty, over the past two thousand years, there are still many ancient books about sericulture, such as "Si Sheng Zhi Shu", "Qimin Yao Shu", "Qin Guan Can Shu", "Bin Feng Guang Yi", "Guang Can Sang Shu", "Sang Sang Ji Yao", "Ye Can Lu", "Chu Jian Pu", etc., which either focus on sericulture or talk about sericulture. These books record the rich experience of the working people of our country in planting mulberry and raising silkworms.

To develop sericulture, it is necessary to breed mulberry trees and develop mulberry gardens. As early as the Western Zhou Dynasty, people used sowing seeds to breed mulberry trees. At the latest in the fifth century AD during the Northern and Southern Dynasties, layering was already used in mulberry breeding. This method is described in "Qimin Yaoshu". Layering uses mulberry branches to breed new mulberry trees, which shortens the growth time a lot compared to sowing seeds. Since the Song and Yuan Dynasties, silkworm farmers in southern my country have invented mulberry grafting technology, which is an advanced mulberry planting technology. It is of great significance to the rejuvenation of old mulberry trees, the preservation of the excellent traits of mulberry trees, the acceleration of mulberry seedling breeding, and the cultivation of excellent varieties. It still plays a major role in production today.

Mulberry leaves are the main food for silkworms. The quality of mulberry leaves is directly related to the health of silkworms and the quality of silk. my country invented the technology of trimming mulberry trees very early. As early as the Western Zhou Dynasty, there were already low mulberry trees, which may be the "ground mulberry" (Lu mulberry) mentioned later. The "Book of Si Sheng" in the Western Han Dynasty specifically describes the cultivation method of this ground mulberry: in the first year, mulberry and millet seeds are planted together. When the mulberry tree grows to the same height as the millet, the mulberry tree is cut down on the flat ground. In the second year, the mulberry tree will grow new branches from the roots. Such mulberry trees are short and easy to pick mulberry leaves and manage. More importantly, such mulberry branches are tender and leaves are fat, which is suitable for raising silkworms. In "Qimin Yaoshu", Jia Sixie quoted an agricultural proverb and gave a positive evaluation of ground mulberry (Lu mulberry), saying: "Lu mulberry produces a lot of cotton and silk, which means that the mulberry is good and has little use." The famous Hu mulberry originated from Lu mulberry. Since the Song Dynasty, people have introduced the excellent mulberry species Lu mulberry from the north to the south using grafting technology. People used the original Jing mulberry as the rootstock and Lu mulberry as the scion. After a long period of practice, they gradually cultivated a new type of Lu mulberry, "Hu mulberry". The formation of Hu mulberry has greatly promoted the development of my country's sericulture industry. The mulberry tree pruning technology has been continuously developed and improved, and the tree shape of mulberry trees has also been constantly changing, from "natural type" to high trunk, middle trunk, low trunk and "ground mulberry", and from "no fist type" to "with fist type". High-quality mulberry leaves can only be produced on new branches. By pruning and cutting off old branches, new branches can be promoted. The new branches absorb a lot of water and nutrients, making the leaves larger and darker green, which not only increases the yield but also improves the quality of the leaves, which is beneficial to silkworm production. This is also a unique creation of the ancient Chinese working people. In the second half of the 19th century, the Japanese also cultivated mulberry trees into various forms based on the records of my country's "Qimin Yaoshu" and other ancient sericulture books.

2. Sericulture Technology (cited by Long Zhijing)

Preparing silkworm eggs is an important part of silkworm breeding. "The Book of Rites: Sacrifices" records "offering seeds and bathing in the river", which shows that as early as more than 2,000 years ago, people already knew to use clean water to bathe the egg surface to protect silkworm eggs. Later, cinnabar solution, salt water, lime water and other drugs with disinfectant effects were developed to disinfect the egg surface. For example, "Chen Fu's Agricultural Book" in the Southern Song Dynasty records: "In spring, when the eggs are about to hatch but not yet hatched, grind cinnabar and bathe them in warm water." This bathing of eggs near the hatching of silkworm eggs is very meaningful for preventing silkworm diseases. Because the egg surface is disinfected by bathing, there will be no bacteria invading the silkworm ants (young silkworms) after the silkworms hatch. We know that many pathogens, such as microparticles and pus viruses, are transmitted through the esophagus. During hatching, silkworm ants have to bite off part of the egg shell before they can hatch. If the egg surface carries these pathogens and is not disinfected, the silkworm ants are very likely to be infected with these diseases when they bite the shell.

At least 1,400 years ago, silkworm farmers had already paid attention to the selection of silkworm seeds. The Qi Min Yao Shu said: "When collecting cocoon seeds, you must take the ones in the middle of the cluster. If they are close to the top, the silk will be thin, and if they are close to the bottom, the eggs will not be produced." The ancients believed that seed selection had two meanings for raising silkworms: one was to eliminate weak and sick silkworm seeds, and the other was to make the growth and development time and speed of the second generation of silkworms consistent, which was convenient for breeding and management. Seed selection includes four items: selecting silkworms, selecting cocoons, selecting moths, and selecting eggs. However, when people first selected seeds, these four items were not fully included. The Qi Min Yao Shu only mentioned that the cocoons "in the middle of the cluster" should be selected as seeds. Since the end of the Song Dynasty, people have further selected seed cocoons, moths, and eggs from various angles, such as the quality of the cocoons, the time and location of the cocoons, the time when the moths emerged from the cocoons, the health of the moths, and the health of the eggs. In the Qing Dynasty, people paid more attention to the selection of silkworms. They knew that only "disease-free silkworms can have disease-free seeds."

Through strict seed selection, a large number of diseased or weak silkworms are eliminated, which improves the physical fitness of the second generation of silkworms and enhances their resistance to diseases. At the same time, it also prevents the transmission of microparticle pathogens and pustular disease viruses to the offspring through embryos to a certain extent. We know that the basic method proposed by Pasteur (1822-1895), a French microbiologist in the 19th century, to prevent the spread of microparticle disease is to strictly select seeds to cut off the embryo transmission route of microparticle pathogens.

The ancients also realized that the growth and development of silkworms are closely related to the surrounding environment. As early as the Qin and Han Dynasties, people knew that appropriate high temperatures and fullness are beneficial to the growth and development of silkworms and can shorten the age of silkworms; conversely, it is not conducive to growth and development, and the age of silkworms must be extended. Sericulture farmers in all dynasties have attached great importance to controlling the living environment of silkworms. "Qimin Yaoshu·Zhongsangzhe Pian" contains a method of placing fires at the four corners of the silkworm room to heat the room to adjust the temperature of the silkworm room, "If the fire is in one place, the temperature will be uneven", "Several people wait and see, and the heat will go away." "Shi Nong Biyong" in the late Jin Dynasty and early Yuan Dynasty also proposed that the silkworm room should be warmer when the silkworms are young, because the weather is still very cold at that time; and after the long sleep, it must be cooler, because the weather is already hot at that time. The New Book of Wuben says: "In wind and rain, day and night, one must always measure the temperature with the body." Silkworm farmers only wear single clothes and compare their own bodies: "If you feel cold, the silkworms must be cold, so add more fire; if you feel hot, the silkworms must be hot, so remove the fire." Under normal circumstances, the comfortable ambient temperature of the human body is roughly similar to the living temperature required by silkworms. It is basically reasonable to adjust the temperature of the silkworm room based on the body's sense of cold and heat. Wang Zhen's Agricultural Book has detailed records on lighting a fire in the silkworm room during the early silkworm period, measuring the temperature with the body, rolling up the curtains for ventilation after a nap, and placing a water jar at the door to create cool air in summer.

On the prevention and treatment of silkworm diseases (note by the author)

In the long-term silkworm production, ancient Chinese silkworm farmers have accumulated rich experience in preventing and treating silkworm diseases. They have adopted many hygiene measures, adding medicine to food, and isolating sick silkworms to prevent the occurrence and spread of silkworm diseases.

In the second century AD, Cui Shi of the Eastern Han Dynasty said in the "Monthly Orders for the Four People": "On the Qingming Festival in March, order the silkworm concubine to clean the silkworm room, paint the gaps and holes, and use hammers to hold the foil cage." This means that the silkworm room and silkworm tools must be repaired and cleaned before raising silkworms. In ancient times, the method of fumigation was invented to disinfect the silkworm room. These sanitation and disinfection work before raising silkworms undoubtedly played a positive role in preventing diseases and insect pests of silkworms. In addition, during the entire breeding process, silkworm feces (silkworm feces) must be removed in time and silkworm tools must be disinfected continuously. The "Essentials of Agriculture and Sericulture" of the Jin and Yuan Dynasties said: "The bottom foil of the silkworm seat must be laid with two pieces. After the silkworms are born, one piece should be rolled out at sunrise every day, and exposed to the sun until the sun sets, and then laid on the bottom of the silkworm foil. The bottom foil is taken out and exposed to the sun as before the next day." Repeated replacement. Using sunlight to disinfect silkworm tools is an economical and practical method.

Drugs can be used to prevent and treat silkworm diseases, including adding drugs to the diet and fumigating drugs. Adding drugs to the diet to prevent and treat silkworm diseases has a history of more than 800 years. "Scholars and Farmers Must Use" says: "Grinding mulberry leaves that are about to fall into the ground can eliminate silkworm fever." Later books such as "Yang Yu Yue Ling" (1633 AD) and "Secrets of Cannabis" also recorded the use of "licorice water", "garlic juice", "shaojiu" and other sprays on the leaves to feed silkworms to prevent and treat various silkworm diseases. Later, different prescriptions were proposed for different symptoms.

Since the Ming Dynasty, people have had a certain understanding of certain infectious silkworm diseases, such as pus disease, softening disease and stiffness disease, and they know how to take elimination or isolation measures to prevent the spread of silkworm diseases.

Silkworm maggot disease is one of the main diseases in the history of silkworm breeding in my country. Maggot disease is the result of the parasitism of silkworm maggots and flies. Flies were called "worms" in ancient times. More than 2,000 years ago, "Er Ya" had the words "Guo He worms and worms". Guo Pu's "Notes" in the Jin Dynasty said: "Now we call pupa worms worms". Pupa worms mean that this worm parasitizes on the pupa. Lu Dian's "Bi Ya" in the late Southern Song Dynasty clearly described this parasitic phenomenon. He said: "Worms, in the old saying, flies lay eggs on the silkworms, and after cocooning, they become maggots, which are commonly called worms. They enter the soil and become flies." Here it says that worms lay eggs on silkworms, and when the silkworms cocoon and pupate, they have become maggots. Tan Zhenmo of the Ming Dynasty further confirmed that the records of his predecessors were completely correct through personal observation. He further pointed out that silkworm maggots and flies mostly occur in the second silkworms, and seven out of ten second silkworms are parasitized. In ancient times, since silkworms were mainly harmed by flies, as the proportion of summer silkworms increased, the problem of fly maggot disease attracted more attention. Although people discovered fly maggot disease very early, there were few records about the prevention and control of silkworm maggot flies in agricultural and sericulture works before the Song Dynasty. After the Song Dynasty, records were common. In the early Yuan Dynasty, the book "Nongsang Jiyao" compiled by the Ministry of Agriculture mentioned the problem of raising summer silkworms and preventing flies many times. It quoted "Scholars and Farmers Must Use" under the "Summer and Autumn Silkworm Methods" and said: "Nowadays, when raising hot silkworms, paper is pasted on the windows to avoid flies and block all the wind coming and going... or use a curtain, tied to the window, to block flies." In "Wang Zhen's Agricultural Book", there is a similar record: "There are summer silkworms and autumn silkworms. Summer silkworms should be kept cool from the ants to the old, but they should avoid flies." This shows that in the Yuan Dynasty, people paid great attention to fly prevention in order to raise summer and autumn silkworms well.

In the works of the Ming Dynasty, there are more records about fly maggot disease and fly prevention. Before Tan Zhenmo wrote Tan Zi Diao Chong, Huangfu Wei's Jie Yi Xin Yu (1582 AD) also talked about "fly maggot disease": "Today's silkworm farmers also have flies deposit their eggs in the bodies of silkworms. After a long time, the eggs will turn into flies and come out of the cocoons." Xu Guangqi also specifically reminded silkworm farmers in the Complete Book of Agricultural Administration, Sericulture, that "both summer and autumn silkworms must be considered for fly removal." Song Yingxing's Tiangong Kaiwu, Naifu Chapter, has such a record: "There are three types of harm to silkworms, sparrows, mice, and mosquitoes. Sparrows do not harm cocoons, mosquitoes do not harm early silkworms, and mice harm them from beginning to end." The "mosquito harm" mentioned here should be a mistake for "fly harm". Because in silkworm production, mosquitoes do not cause harm, and in the history of silkworm breeding, there is only the saying that "flies do not harm early silkworms."

During the Qing Dynasty colonial era (author's note), maggot disease caused serious concern among people. During the Tongzhi period, Shen Bingcheng said in his book "Collection of Sericulture": "The original silkworm is the summer silkworm, also known as the second silkworm, ... it will be old on the 22nd day, and it is most afraid of big flies." Shen Bingcheng was from Zhejiang. He lived in the silkworm breeding area and served as the governor of Changzhou, Zhenjiang, Tongzhou, and Haining in the Qing Dynasty. He once promoted sericulture in Zhenjiang. He said that raising summer silkworms "is most afraid of big flies", which is obviously an experience summary based on the actual situation at that time. Here he used the adverb "most" to draw people's special attention. Yu Yong also said in his Essentials of Sericulture (1866-1874 AD): "Silkworms are more afraid of flies. No matter how big or small they are, if they are bitten by flies, maggots will appear in the cocoon and drill out of it after the silkworms have grown old and become cocoons. The silkworm pupa will die and will no longer become a moth. After three or four days, the pupa will rot and contaminate the cocoon." Yu Yong was from Wuxing, Zhejiang Province. Although his account was relatively crude, it was also a conclusion drawn from practice and observation. He pointed out that silkworm pupae parasitized by fly maggots will die, and the rotting corpses of the dead pupae will also contaminate the cocoon silk.

The most detailed description of polymorphic silkworm maggot flies and their damage is in the book "Sericulture" (1896 AD) written by Zhao Jingru. The book contains the following record: "There is also a kind of hemp fly, which does not eat silkworms, but is the most harmful. This hemp fly is different from ordinary hemp flies. Its body and wings are white, covered with black hair, and its wings are spread wide, which looks quite ferocious. It is quite smart and flies very fast. It always flies unsteadily and does not easily rest. If it occasionally rests, it will fly away when it sees a shadow, making it very difficult to catch. When it comes, it will lay a white egg, which is as thin as a lice, when it rests on the silkworm. After two days, the place where the egg is laid turns black, and the maggots have entered the silkworm's body, in the silk material inside the skin, and feed exclusively on the silkworm meat. After six or seven days, the maggots are old and have a mouth full of Two black teeth, the clamping hand is slightly painful. Because the silkworm does not damage the silk material, it can still make cocoons. The old maggots use the two black teeth to gnaw the cocoons, forming small holes, which are the cocoons of infestation. The silk of infested cocoons cannot be reeled. The maggots come out one day and become pupae with red shells. After twelve or thirteen days, they break out of the shell and still become large white flies. Fortunately, the weather is still cool during the second and third sleeps, so there are not many such flies. When the weather is warm, there are many flies and there is no way to drive them away. When the silkworms just wake up from the long sleep, they will be attacked by maggots and die before they can make cocoons. Therefore, the summer silkworms do not avoid these flies, and the silkworms will not be left behind. "This record gives a very detailed description of the morphology and living habits of silkworm maggot flies. As Zou Shuwen pointed out in the book "History of Chinese Entomology": Zhao Jingru's detailed observation and description of silkworm maggot flies in "On Sericulture" may have accepted the modern Western scientific methods. This also further confirms that the records of silkworm maggot diseases in ancient Chinese books are basically correct.

After long-term breeding and selection by people of all generations, the characteristics of silkworms have changed greatly, and various types of varieties have been formed in various historical periods and regions. During the Song and Yuan Dynasties, although the northern part of my country mainly bred monovoltine three-sleeping silkworms, the southern part of China mainly bred monovoltine or bivoltine four-sleeping silkworms. Three-sleeping silkworms have stronger disease resistance than four-sleeping silkworms and are easier to raise. However, from the perspective of silk production, the cocoons of four-sleeping silkworms are better than those of three-sleeping silkworms. After long-term cultivation, the Jiangsu and Zhejiang regions in southern my country finally succeeded in raising four-sleeping silkworms and bred many excellent varieties. The successful breeding and promotion of the difficult-to-raise four-sleeping silkworms is an improvement in silkworm production.

In order to develop silk production, in ancient my country, in addition to raising spring silkworms, summer silkworms and autumn silkworms were also raised, and even multiple batches of silkworms were raised in a year. As early as the book "Zhou Li", "original silkworms" were mentioned, and "original" means "again". Original silkworms are silkworms raised for the second hatching in a year, that is, summer silkworms. "Yi Lin" written by Jiao Gan (Yanshou) in the Han Dynasty records that "autumn silkworms fail to mature and winter silkworms do not reproduce". It can be seen that people at that time not only raised summer silkworms, but also raised autumn silkworms and winter silkworms. In order to raise multiple batches of silkworms in a year, in addition to using polymorphic natural reproduction, the ancients invented a method of low-temperature precipitating green to produce live seeds more than 1,600 years ago. This method uses low temperature to inhibit the silkworm eggs of a bimorphic silkworm, delaying its hatching. In this way, a silkworm can hatch several generations continuously in a year, creating favorable conditions for raising multiple batches of silkworms in a year. This is another important creation in ancient my country's sericulture production technology. The use of artificial low temperature to produce live seeds fully reflects the wisdom of the ancient Chinese people. Before the invention of artificial hatching, in order to raise multiple batches of silkworms in a year, people could only use natural polyvoltine silkworms to propagate. However, the cocoons and silk produced by polyvoltine silkworms are far inferior to those of bivoltine silkworms in both quantity and quality. In order to raise silkworms in batches multiple times a year and obtain more and better cocoons and silk, our ancestors creatively used artificial low-temperature to accelerate the growth of bivoltine silkworms, so that they could hatch several batches of silkworms continuously in a year. At the same time, the eggs produced by each batch of such silkworms were hatched under the influence of natural high temperature, thus obtaining batches of multi-year silkworms. Although the eggs produced by such silkworms can only be hatched in the spring of the following year, they are still welcomed by silkworm farmers because of their better quality. In this way, the problem of propagation of silkworms in multiple batches can be solved, and better silk can be obtained as much as possible.

It is worth mentioning that in the Ming Dynasty, silkworm farmers discovered the hybrid advantage of silkworms in the production of summer silkworm seeds. Song Yingxing of the Ming Dynasty said in Tiangong Kaiwu: "All silkworms have two kinds, early and late. Late-seed silkworms appear five or six days before early-seed silkworms every year, and they also cocoon earlier, and their cocoons are one-half lighter." He also said: "Nowadays, some people in the cold family mate early males with late females, and they produce good seeds, which is different." The "early seeds" mentioned in Tiangong Kaiwu are monovalent silkworms, and the "late seeds" are divalent silkworms. Therefore, the so-called "early males mate late females" is the hybridization of monovalent male silkworms and divalent female silkworms. According to modern silkworm hybridization experiments, the hybrids produced by "early males mate late females" are divalent, so they can continue to be raised in summer as summer silkworm seeds. Tiangong Kaiwu pointed out that "early males mate late females" produced "good seeds", that is, excellent hybrids. This is the earliest record in the world on the use of hybrid advantage of silkworms.

my country is also the world's largest producer of tussah silk.

Tussah silkworms, also known as mountain silkworms or wild silkworms, mainly feed on tussah leaves. Shandong Peninsula in my country is the birthplace of free-range tussah silkworms. People there have been using tussah silkworm cocoons for a long time. According to ancient records, as early as the fourth year of Emperor Yuan of the Han Dynasty (40 BC), people in Penglai and Ye County, Shandong Province, had already harvested wild tussah silkworm cocoons and made them into silk floss. Later, people gradually learned to use tussah silkworm cocoon silk to weave silk. By the Ming Dynasty, using tussah silkworm cocoon silk to weave silk clothes had become popular throughout the country.

In the Ming Dynasty, Shandong silkworm farmers had already developed a relatively mature method of raising tussah silkworms. In the early Qing Dynasty, Sun Tingquan of Yidu, Shandong, also wrote a book called "On Mountain Silkworms", which specifically introduced the technology of raising tussah silkworms. The book said that at that time, tussah silkworms were raised everywhere in the mountainous areas of Jiaodong. Soon, raising tussah silkworms gradually expanded to other parts of my country, first to the Liaodong Peninsula across the sea from Shandong. This place gradually became the second center of raising tussah silkworms in my country. Then the method of raising tussah silkworms spread to Henan and Shaanxi, and later to more distant places such as Yunnan and Guizhou.

A side story of sericulture technology

For all sericulture countries in the world, the original silkworm breeds and sericulture methods were introduced directly or indirectly from my country.

Korea is a close neighbor of my country, and the people of the two countries have had close exchanges for a long time. According to the records in ancient books, my country's silkworm species and silkworm breeding methods were introduced to Korea as early as the 11th century BC. According to legend, Japan's silkworm breeding methods were introduced from China during the reign of Qin Shihuang. Later, the Japanese sent people to China and Korea many times to learn from them, or recruited Chinese technicians to Japan to impart their experience in order to promote the development of silkworm breeding. Until modern times, Japan continued to introduce excellent silkworm varieties and advanced mulberry planting techniques from my country.

The beautiful silk produced by the working people in ancient my country was transported to Persia, Rome and other places very early. In the third year of Jianyuan in the Western Han Dynasty (138 BC), Emperor Wu of the Han Dynasty sent Zhang Qian to the Western Regions, and the farthest he reached was Central Asia. The ancient Chinese silk was generally transported along the road Zhang Qian took to the Western Regions, from the northern foot of the Kunlun Mountains or the southern foot of the Tianshan Mountains to the west through the Pamirs, through Central Asia, and then to Persia, Rome and other countries. This is the world-famous "Silk Road". Later, silkworm species and silkworm breeding methods were also first spread from the inland to Xinjiang, and then from Xinjiang to Arabia, Africa, and Europe via the "Silk Road".

In the seventh century, sericulture spread to Arabia and Egypt. In the tenth century, it spread to Spain. In the eleventh century, it spread to Italy. In the fifteenth century, silkworm and mulberry seeds were brought to France, and from then on, France began to plant mulberry trees, raise silkworms and weave silk. Seeing that France was making a lot of money from raising silkworms, Britain followed suit, and sericulture spread from France to Britain.

In America, it is said that Mexico had already been raising silkworms in the mid-16th century, but large-scale silkworm production in America did not develop until the 17th century. At that time, British colonialists believed that the climate in its American colonies was suitable and the land was fertile, and that it would be profitable to develop silkworms, so they carried out large-scale silkworm breeding experiments in the American colonies.

4. Why do silkworms shed their skin?

During the growth and development of silkworms, the epidermis cannot grow with the growth of the body. When the growth of the silkworm's body is restricted, the silkworm will shed its skin. Silkworms are transformed from silkworm eggs. Silkworm eggs are less than half the size of sesame seeds. When they are first laid, they are milky yellow and spherical, like small meat patties. After a long period of gestation, the silkworm eggs turn gray, and after a period of time, they magically turn black. Under a magnifying glass, you can see the young silkworms bending in the eggshell. The clever silkworms wait until the end of spring and the beginning of summer, and they are impatient to bite through the eggshell with their little mouths, and drill out of the cave with their little heads poking out. The newly hatched silkworms are very small and black like ants, so silkworm breeders vividly call them "ant silkworms". Silkworms have the characteristics of insects, with fine hairs all over their bodies and fourteen legs (six on the head and eight on the body). Many of the legs can firmly attach to objects, which provides them with great convenience for finding food. Time passes, and the ant silkworms grow up day by day. But the skin of silkworms is like the clothes we wore when we were children. It cannot grow with the body, so they adopt the method of changing the outer skin as their bodies grow to solve the problem. Silkworms shed their skin four times in their life. About two weeks after birth, silkworms begin to shed their skin for the first time. Perhaps because of the "pain", silkworms shed their skin carefully and skillfully. I once timed it with a watch, and the whole process only took seven or eight minutes. This is a wonderful process. If you observe carefully, you will find that the silkworms do not eat for a long time before shedding their shells. They stretch their heads lazily, and although they continue to excrete, their bodies become loose and thin, and their appearance is like the wrinkled face of an old man. At the beginning, the silkworms split open a hole on the top of their heads, and the head shell falls off from the top of their heads. But it is really not easy to take off the "outer coat". The silkworm has its own good way. It uses its tail to fix its body. When its body moves forward a little, its tail pulls the outer skin back a little. In this way, the silkworm finally takes off its outer coat. After the silkworm sheds its skin twice, its body color will gradually turn white, and the hair on its body will degenerate, and obvious links will appear on its body. After the third molting, a small thorn cone will grow from its tail, and its body will become crystal clear. At this time, you can see the silk tube inside the silkworm's body. Silkworms mainly feed on mulberry leaves. The ancestors of silkworms really understood scientific principles. Among the hundreds of thousands of plants in the world, they chose mulberry leaves. In fact, it is not surprising. You might as well pick a mulberry leaf, tear it open or rub it with your hands, and you will find that the mulberry leaf is full of milky white juice. The biology teacher told me that this juice contains a lot of protein. Silkworms eat mulberry leaves and absorb rich nutrients. Not only can they thrive day by day, but they also provide enough nutrients for making silk in the future. Silkworms are quite "vain" animals. She is very greedy and never knows how to save. She keeps eating from morning to night. Silkworms pursue fullness. It is appropriate to describe her as a noble lady in the Tang Dynasty before she cocoons. Silkworms are very particular about eating mulberry leaves. They use their mouths to "cut" food bit by bit along the edge of the leaves, from the outside to the inside, leaving regular traces like saw teeth. The process of silkworms eating was called "cannibalism" by the ancients, and the Xinhua Dictionary explains it as "gradual invasion". In fact, there is a reason why silkworms eat like this, which is determined by the special structure of their mouths. If you observe silkworms closely, you will see that their mouths are divided into two. When they gnaw, the two petals of their mouths are like a pair of scissors, so they can only "cut food" along the edge of the mulberry leaves. After more than two months, the life of silkworms reaches its climax, and they want to create a miracle. First, they want to build a beautiful "house" for themselves. Don't underestimate them. Silkworms are born to be skilled craftsmen with their own unique architectural skills. They first carefully select a corner, and then use their building material - silk. They use their tail to fix their body, use their mouth to aim at the selected position, spit out silk to fix one end, and then twist their body in place, and use their mouth to spit out silk to the other end to fix it. : : : : : : : : : : : : : : : : : : : : : : : : : : : : : :