CATDOLL : CATDOLL: Identification and prevention of silkworm diseases

In rural silkworm production, the main silkworm diseases are viral diseases, followed by fungal diseases and bacterial diseases. There are four types of viral diseases: blood-type purulent disease, midgut-type purulent disease, viral sclerotinia, and pyogenic tuberculosis. Bacterial diseases are also called softening diseases, which are divided into bacterial septicemia, bacterial poisoning, and bacterial enteropathy.

① The body segments of the silkworm are swollen, the body color is milky white, and it crawls frantically. The body wall is easily broken. The big silkworms often crawl to the edge of the silkworm plaque and fall to the ground and die, and milky white blood flows out in a thick juice-like state. It can be diagnosed as blood-type pus disease;

② The diseased silkworms develop slowly, are thin and small, and the size of the group varies greatly. They are not active in eating mulberry and moving, and often lie still around the silkworm seat or in the residual mulberry. Their chests are transparent and hollow, and they excrete milky white mucus silkworm feces. Tearing the body wall on the back of the diseased silkworm, milky white horizontal stripes can be seen at the rear end of the midgut, which can be diagnosed as midgut purulent disease;

③ If the silkworms are uneven in size, have poor appetite, empty heads, diarrhea, head and chest erect and motionless, have shiny yellow body color, and discharge brown dirty liquid, it can be diagnosed as pustular disease;

④ Soon after the death of the diseased silkworm, dark green corpse spots first appear on the back of the thorax or 1 to 3 segments of the abdomen, and the corpse spots quickly expand and turn black. Finally, the whole body rots and oozes dark brown contaminated fluid, which can be diagnosed as black chest septicemia;

⑤ The color of the diseased silkworm corpse changes slowly, and gradually turns red as the corpse tissue dissociates and liquefies, and finally flows out red dirty liquid, which can be diagnosed as fungal septicemia;

⑥ Soon after the death of the diseased silkworm, oily green corpse spots often appear on the back of the chest, the corpse does not turn black, and the blood is turbid and grayish white, which can be diagnosed as green-head septicemia;

⑦ The silkworm has oily spots on its body. When it first dies, its head and chest extend forward and feel slightly elastic. Soon, it gradually becomes rigid and its body is grayish white. This can be diagnosed as white muscardine disease.

⑧ The silkworms have large black trumpet-shaped spots on their bodies, and their body color sometimes turns purple. The fifth-instar silkworms that are parasitized usually mature early, which can be diagnosed as myiasis.

⑨ If silkworms crawl in piles, shake their heads, roll over, spit out large amounts of water, or have bent bodies, they may be diagnosed with pesticide poisoning.

Prevention and treatment methods:

① If fungal disease is found, the disinfection of silkworm bodies and silkworm seats should be strengthened. Anti-rigidity powder should be used once every morning and fresh lime powder should be used once every night. Fumigation with toxic chlorpyrifos (g/cubic meter) can be used for 30 minutes through closed doors and windows during the silkworm period. 402 antibacterial agent can also be used to soak the net or spray the body. For 1-3 instar silkworms, 500-700 times the liquid should be used to soak the silkworm net, and the silkworm body should be directly covered after squeezing dry. For 4-5 instar silkworms, 1500-2000 times the liquid should be used to spray the body directly.

② If a virus disease is found, anti-stiffness powder should be used once in the morning and fresh lime powder should be used once in the evening to disinfect the silkworm bodies and silkworm seats. At the same time, adding food for pus can inhibit the occurrence of virus diseases. In addition, during the silkworm period, fumigation with fumigation chlorhexidine (1 gram/cubic meter) can be used to fumigate the closed doors and windows for 30 minutes to prevent and treat blood-type pus diseases.

③ If bacterial disease is found, the silkworm room should be equipped with screen doors and windows, and 500 times diluted silkworm fly killer should be added to the feed or 300 times diluted silkworm fly killer should be sprayed on the body every other day.

④ If pesticide poisoning is found, first find out the source of the poison. If it is caused by mulberry leaves, immediately sprinkle fresh lime powder to stop the mulberry poisoning, open the doors and windows for ventilation, add a net to feed fresh non-toxic mulberry leaves and then remove the sand. If it is caused by the smell of outdoor pesticides drifting into the silkworm room, immediately close the doors and windows and hang wet cloth and curtains on the doors and windows.

I. Viral diseases 1. Blood-type purulent disease (1) Body swelling, milky white and shiny; (2) Internodes bulge to form high-node silkworms or internodes fold to form bamboo-node silkworms; (3) Crawl frantically around silkworms and fall to the ground; (4) The disease occurs when the silkworm is about to fall asleep and cannot fall asleep and dies; (5) Skin is easily broken and blood is milky white; (6) Microscopic examination of blood shows polyhedrons; (7) Healthy silkworms eat polyhedrons until the disease occurs, usually about 4 to 7 days. 2. Midgut-type purulent disease (1) Irregular development, long period, little food intake, weak vitality, thin body, white clay color, frequent diarrhea; (2) Squeeze the tail of the diseased silkworm to find sticky, yellow-green feces, and in severe cases, milky white sticky feces; (3) Blood is normal, there are milky white horizontal stripes in the midgut, and hindgut erosion; (4) Microscopic examination of midgut tissue shows polyhedrons; (5) Healthy silkworms eat polyhedrons until the disease occurs, usually about 7 days. 3. Densoblastic Disease (1) Uneven development, reduced mulberry feeding, no feeding, leaf trampling, weak body, but no feces or diarrhea in the tail, vomiting water when dead; (2) Manifestations are empty head or shrinkage; (3) No polyhedron under microscopic examination. 4. Viral Disease Prevention and Control Methods (1) Before the silkworm period, the silkworm room, silkworm tools, and silkworm rearing environment should be thoroughly cleaned and disinfected; (2) Strengthen feeding management: pay attention to moisture retention, heat preservation, and improve leaf quality during the young silkworm period. During the adult silkworm period, feed the silkworms well, ventilate, prevent starvation, steam and heat, and prevent silkworm body trauma; (3) Frequently use fresh weathered lime powder as drying material to disinfect silkworm bodies and silkworm seats; (4) Do a good job in mulberry disease and insect control to prevent cross infection caused by foreign viruses; (5) Deal with sick and dead silkworms properly, and strictly prohibit feeding chickens and ducks; (6) Deeply bury mulberry sand; (7) Strictly eliminate late-dormant silkworms, sick silkworms, very small silkworms, and abnormal silkworms. 2. Fungal parasitic diseases 1. Beauveria muscardine (1) In the late stage of the disease, the silkworm dies. Before death, it spits out a little water, and its body is soft and straight. The skin is light red, and becomes stiff and white after 2 days. (2) In case of disease during sleep, the silkworms are mostly peeling, but not shed. The dead silkworms are dirty brown and damp. (3) Microscopic examination of the blood of the diseased silkworms shows cylindrical blastospores of Beauveria muscardine. (4) Infected silkworms usually die within 3 to 7 days. 2. Aspergillus disease (1) The disease develops quickly in the young silkworm stage, with a straight chest and a soft tumor on the tail. At first glance, it looks like pesticide poisoning. The dead body is dark brown, and after 1 to 2 days, white fluffy hyphae, green-brown and brown conidia grow. (2) In the adult silkworms, large yellow-brown lesions can be seen on the skin of the tail, without blastospores. Nutritional hyphae can be detected under a microscope at the lesions. (3) The disease is acute in the first to second instars, and the silkworms die 2 to 3 days after infection. 3. Prevention and control methods (1) Improve the silkworm rearing environment and clean and disinfect the silkworm tools in the silkworm room; (2) Do a good job of disease prevention and hygiene during the silkworm period, and strive to keep the silkworm seats clean and hygienic. In places with high humidity at night, often use straw to smoke; (3) Use anti-rigidity agents to disinfect the silkworm bodies and silkworm seats and smoke disinfection; (4) Silkworm feces and diseased silkworms are buried deep to rot, and silkworm feces must not be spread out around the silkworm room to dry; (5) Do a good job of preventing mulberry diseases and insect pests to reduce cross-infection. III. Bacterial parasitic diseases 1. Septicemia (1) When dying, the silkworm stops eating, moves sluggishly, spits water or excretes soft feces. The silkworms get sick during the young silkworm period and excrete abnormal soft feces, beads of feces or dirty liquid; (2) The chest of the newly dead silkworms is swollen, the internodes are tightened, and there is temporary rigor mortis; (3) The body gradually becomes soft and straight, and black chest, blue head or slightly reddish corpse spots appear, and it rots rapidly with a foul odor; (4) Microscopic examination of the blood of newly dead silkworms shows the presence of pathogens. 2. Sudden collapse (1) Rapid onset, short course, sluggish or intermittent crawling like a drunk, stop eating, paralyzed and dead; (2) The body is stretched out, hollow at both ends, with reddish-brown dirty liquid at the anus. 3. Prevention and control methods (1) Prevent trauma: operate silkworm rearing, collect cocoons; (2) Keep silkworm seats clean; (3) Use fresh mulberry leaves; (4) Add chloramphenicol or erythromycin to the diet. IV. Pests 1. Maggot disease: There are large dark brown spots on the skin of diseased silkworms. Prevention and control measures: Install screens or fly-proof nets on the doors and windows of the silkworm room, and use fly killer regularly. 2. Tick disease: The front half of the body of the diseased silkworm is bent and shaking, and it is restless. It vomits water, excretes soft feces, and prolapses its anus. Finally, it paralyzed and dies. Most of the silkworms killed in sleep do not shed their skin. Prevention and control measures: Do not pile up cotton, straw and other sundries in the silkworm room. Use chloramphenicol when diseased silkworms are found. V. Poisoning 1. Pesticide poisoning

Identification of silkworm diseases. ① The body segments of silkworms are swollen, the body color is milky white, they crawl frantically, the body wall is easily broken, and the big silkworms often crawl to the edge of the silkworm plaque and fall to the ground and die, and milky white blood flows out in a thick juice-like state, which can be diagnosed as blood-type pus disease; ② The diseased silkworms develop slowly, are thin, and the size of the group development varies greatly. They are not active in eating mulberry and moving, and often lie still around the silkworm seat or in the residual mulberry. The chest is transparent and hollow in appearance, and they discharge silkworm feces with milky white mucus. Tearing the back of the body wall of the diseased silkworm, milky white horizontal stripes can be seen at the posterior end of the midgut, which can be diagnosed as midgut purulent disease; ③ The silkworms are uneven in size, have poor appetite, empty heads, diarrhea, and their head and thorax are raised and motionless, with shiny yellow body color and brown dirty liquid discharge, which can be diagnosed as pyogenic disease; ④ Shortly after the death of the diseased silkworm, dark green corpse spots first appear on the back of the thorax or 1 to 3 segments of the abdomen, which quickly expand and turn black, and finally the whole body rots and discharges dark brown contaminated liquid, which can be diagnosed as black chest septicemia; ⑤ The color of the corpse of the diseased silkworm changes slowly, and gradually turns red as the corpse tissue dissociates and liquefies, and finally discharges red dirty liquid, which can be diagnosed as fungus. Septicemia; ⑥ Soon after the death of the diseased silkworm, oily green corpse spots often appear on the back of the thorax, the corpse does not turn black, and the blood is turbid and grayish white, which can be diagnosed as green-headed septicemia; ⑦ There are oily spots on the body surface of the silkworm. When it first dies, the head and thorax extend forward, and it feels slightly elastic to the touch. Soon it becomes rigid and the corpse is grayish white, which can be diagnosed as white muscular disease; ⑧ There are large black trumpet-shaped spots on the body surface of the silkworm, and the body color sometimes turns purple. The fifth-instar silkworms that are parasitized generally have premature maturity, which can be diagnosed as myiasis; ⑨ Silkworms that crawl in piles, shake their heads, roll over, spit out a lot of water, and have bent bodies can be diagnosed as pesticide poisoning.

3. Main prevention and control measures for silkworm diseases. After a silkworm disease occurs, the dead silkworms should be picked out in time and placed in a lime vat, and then buried deep. While strengthening the feeding management such as raising silkworms in batches and removing silkworm feces, corresponding technical measures should be taken according to different types of silkworm diseases to control the spread of silkworm diseases.

① If fungal disease is found, the disinfection of silkworm bodies and silkworm seats should be strengthened. Anti-rigidity powder should be used once every morning and fresh lime powder should be used once every night. Fumigation with toxic chlorpyrifos (g/cubic meter) can be used for 30 minutes through closed doors and windows during the silkworm period. 402 antibacterial agent can also be used to soak the net or spray the body. For 1-3 instar silkworms, 500-700 times the liquid should be used to soak the silkworm net, and the silkworm body should be directly covered after squeezing dry. For 4-5 instar silkworms, 1500-2000 times the liquid should be used to spray the body directly.

② If a virus disease is found, anti-stiffness powder should be used once in the morning and fresh lime powder should be used once in the evening to disinfect the silkworm bodies and silkworm seats. At the same time, adding food for pus can inhibit the occurrence of virus-carrying diseases in the sick shed. In addition, during the silkworm period, fumigation with fumigation chlorhexidine (1 gram/cubic meter) can be used to fumigate the closed doors and windows for 30 minutes to prevent and control blood-type pus diseases.

1. Types of silkworm diseases. Silkworm diseases can be divided into infectious silkworm diseases and non-infectious silkworm diseases. ① Infectious silkworm diseases include viral diseases, bacterial diseases, fungal diseases and protozoan diseases. They are caused by pathogenic microorganisms invading the silkworm body and multiplying in the body, and can be transmitted to healthy silkworms through sick silkworms. ② Non-infectious silkworm diseases are caused by insect poisoning, mechanical trauma, etc., which will not be transmitted from sick silkworms to healthy silkworms, such as maggot disease and poisoning disease.

Silkworm diseases in rural silkworm production are mainly viral diseases, followed by fungal diseases and bacterial diseases. There are four types of viral diseases, including blood-type pus disease, midgut-type pus disease, viral softening disease, and pus tuberculosis. Bacterial diseases are also called softening diseases, which are divided into bacterial septicemia, bacterial poisoning disease, and bacterial enteric disease. Among them, black chest, ling fungus, and blue head septicemia in bacterial septicemia are common in production; fungal diseases are also called stiff diseases, which are usually divided into white stiffness, yellow stiffness, green stiffness, and oak Aspergillus disease according to the color of the zombies, among which white stiffness is the most harmful. Among non-infectious silkworm diseases, fly maggots and various pesticide poisonings are common in production.

2. Identification of silkworm diseases. ① The body segments of silkworms are swollen, the body color is milky white, they crawl frantically, the body wall is easily broken, and the big silkworms often crawl to the edge of the silkworm plaque and fall to the ground and die, and milky white blood flows out in a thick juice-like state, which can be diagnosed as blood-type pus disease; ② The diseased silkworms develop slowly, are thin, and the size of the group varies greatly. They are not active in eating mulberry and moving, and often lie still around the silkworm seat or in the residual mulberry. The chest is transparent and hollow, and they excrete silkworm feces with milky white mucus. Tear the back of the body wall of the diseased silkworm, and milky white horizontal stripes can be seen at the posterior end of the midgut, which can be diagnosed as midgut purulent disease; ③ The silkworms are uneven in size, have poor appetite, empty heads, diarrhea, and their head and thorax are raised and motionless. Their body color is shiny yellow and they discharge brown dirty liquid. This can be diagnosed as pyogenic disease; ④ Shortly after the death of the diseased silkworm, dark green corpse spots first appear on the back of the thorax or 1 to 3 segments of the abdomen. The corpse spots quickly expand and turn black, and finally the whole body rots and discharges dark brown contaminated liquid. This can be diagnosed as black chest septicemia; ⑤ The corpse of the diseased silkworm changes color slowly, and gradually turns red as the corpse tissue dissociates and liquefies, and finally discharges red dirty liquid, which can be diagnosed as spiritual disease. ⑥ Soon after the death of the diseased silkworm, oily green corpse spots often appear on the back of the thorax, the corpse does not turn black, and the blood is turbid and grayish white, which can be diagnosed as green-headed septicemia; ⑦ There are oily spots on the body surface of the silkworm. When it first dies, the head and thorax extend forward and are slightly elastic to the touch. Soon it becomes stiff and the corpse is grayish white, which can be diagnosed as white muscular disease; ⑧ There are large black trumpet-shaped spots on the body surface of the silkworm, and the body color sometimes turns purple. The fifth-instar silkworms that are parasitized generally have precocious maturity, which can be diagnosed as myiasis; ⑨ Silkworms that crawl in piles, shake their heads, roll over, spit out a lot of water, and have bent bodies can be diagnosed as pesticide poisoning.

3. Main prevention and control measures for silkworm diseases. After a silkworm disease occurs, the dead silkworms should be picked out in time and placed in a lime vat, and then buried deep. While strengthening the feeding management such as raising silkworms in batches and removing silkworm feces, corresponding technical measures should be taken according to different types of silkworm diseases to control the spread of silkworm diseases.

① If fungal disease is found, the disinfection of silkworm bodies and silkworm seats should be strengthened. Anti-rigidity powder should be used once every morning and fresh lime powder should be used once every night. Fumigation with toxic chlorpyrifos (g/cubic meter) can be used for 30 minutes through closed doors and windows during the silkworm period. 402 antibacterial agent can also be used to soak the net or spray the body. For 1-3 instar silkworms, 500-700 times the liquid should be used to soak the silkworm net, and the silkworm body should be directly covered after squeezing dry. For 4-5 instar silkworms, 1500-2000 times the liquid should be used to spray the body directly.

② If a virus disease is found, anti-stiffness powder should be used once in the morning and fresh lime powder should be used once in the evening to disinfect the silkworm bodies and silkworm seats. At the same time, adding food for pus can inhibit the occurrence of virus diseases. In addition, during the silkworm period, fumigation with fumigation chlorhexidine (1 gram/cubic meter) can be used to fumigate the closed doors and windows for 30 minutes to prevent and treat blood-type pus diseases.

③ If bacterial disease is found, the silkworm room should be equipped with screen doors and windows, and 500 times diluted silkworm fly killer should be added to the feed or 300 times diluted silkworm fly killer should be sprayed on the body every other day.

④ If pesticide poisoning is found, first find out the source of the poison. If it is caused by mulberry leaves, immediately sprinkle fresh lime powder to stop the mulberry poisoning, open the doors and windows for ventilation, add a net to feed fresh non-toxic mulberry leaves and then remove the sand. If it is caused by the smell of outdoor pesticides drifting into the silkworm room, immediately close the doors and windows and hang wet cloth and curtains on the doors and windows.

I. Viral diseases 1. Blood-type purulent disease (1) Body swelling, milky white and shiny; (2) Internodes bulge to form high-node silkworms or internodes fold to form bamboo-node silkworms; (3) Crawl frantically around silkworms and fall to the ground; (4) The disease occurs when the silkworm is about to fall asleep and cannot fall asleep and dies; (5) Skin is easily broken and blood is milky white; (6) Microscopic examination of blood shows polyhedrons; (7) Healthy silkworms eat polyhedrons until the disease occurs, usually about 4 to 7 days. 2. Midgut-type purulent disease (1) Irregular development, long period, little food intake, weak vitality, thin body, white clay color, frequent diarrhea; (2) Squeeze the tail of the diseased silkworm to find sticky, yellow-green feces, and in severe cases, milky white sticky feces; (3) Blood is normal, there are milky white horizontal stripes in the midgut, and hindgut erosion; (4) Microscopic examination of midgut tissue shows polyhedrons; (5) Healthy silkworms eat polyhedrons until the disease occurs, usually about 7 days. 3. Densoblastic Disease (1) Uneven development, reduced mulberry feeding, no feeding, leaf trampling, weak body, but no feces or diarrhea in the tail, vomiting water when dead; (2) Manifestations are empty head or shrinkage; (3) No polyhedron under microscopic examination. 4. Viral Disease Prevention and Control Methods (1) Before the silkworm period, the silkworm room, silkworm tools, and silkworm rearing environment should be thoroughly cleaned and disinfected; (2) Strengthen feeding management: pay attention to moisture retention, heat preservation, and improve leaf quality during the young silkworm period. During the adult silkworm period, feed the silkworms well, ventilate, prevent starvation, steam and heat, and prevent silkworm body trauma; (3) Frequently use fresh weathered lime powder as drying material to disinfect silkworm bodies and silkworm seats; (4) Do a good job in mulberry disease and insect control to prevent cross infection caused by foreign viruses; (5) Deal with sick and dead silkworms properly, and strictly prohibit feeding chickens and ducks; (6) Deeply bury mulberry sand; (7) Strictly eliminate late-dormant silkworms, sick silkworms, very small silkworms, and abnormal silkworms. 2. Fungal parasitic diseases 1. White muscardine disease (1) In the late stage of the disease, the silkworm dies. Before death, it spits out a little water, and its body is soft and straight. The skin is light red, and becomes stiff and white after 2 days. (2) In case of disease during sleep, the silkworms are mostly peeling, but not molting. The dead silkworms are dirty brown and damp. (3) Microscopic examination of the blood of the diseased silkworms shows cylindrical blastospores of white muscardine bacteria. (4) Infected silkworms usually die within 3 to 7 days. 2. Aspergillus disease (1) The disease develops quickly in the young silkworm stage, with a straight chest and a soft tumor on the tail. At first glance, it looks like pesticide poisoning. The dead body is dark brown, and after 1 to 2 days, white fluffy hyphae, green-brown and brown conidia grow. (2) In case of disease in adult silkworms: large yellow-brown lesions can be seen on the skin of the tail, without blastospores. Vegetative hyphae can be detected under a microscope at the lesions. (3) The disease is acute in the first to second instars, and the silkworms die 2 to 3 days after infection. 3. Prevention and control methods (1) Improve the silkworm rearing environment and clean and disinfect the silkworm tools in the silkworm room; (2) Do a good job of disease prevention and hygiene during the silkworm period, and strive to keep the silkworm seat clean and hygienic. In places with high humidity at night, often use straw to wrap silver and smoke; (3) Use anti-rigidity agents to disinfect the silkworm body and silkworm seat and smoke disinfection; (4) Silkworm feces and diseased silkworms are buried deep to rot, and silkworm feces must not be spread out around the silkworm room to dry; (5) Do a good job of preventing mulberry diseases and insects to reduce cross-infection. III. Bacterial parasitic diseases 1. Septicemia (1) When dying, the silkworm stops eating, moves sluggishly, vomits water slightly or excretes soft feces. The silkworms get sick during the young stage and excrete abnormal soft feces, beads of feces or dirty liquid; (2) The chest of the newly dead silkworms is swollen, the internodes are tightened, and there is temporary rigor mortis; (3) The body gradually becomes soft and straight, and black chest, blue head or slightly reddish corpse spots appear, and it rots and has a foul odor; (4) Microscopic examination of the blood of newly dead silkworms shows the presence of pathogens. 2. Sudden collapse (1) Rapid onset, short course, sluggish or intermittent crawling like a drunk, stop eating, paralyzed and dead; (2) The body is stretched out, hollow at both ends, with reddish-brown dirty fluid at the anus. 3. Prevention and control methods (1) Prevent trauma: operate silkworm rearing, collect cocoons; (2) Keep silkworm seats clean; (3) Use fresh mulberry leaves; (4) Add chloramphenicol or erythromycin to the diet. IV. Pests 1. Myiasis: Large dark brown spots appear on the skin of diseased silkworms. Prevention and control measures: Install screens or fly-proof nets on the doors and windows of the silkworm room, and use fly killer regularly. 2. Tick disease: The front half of the diseased silkworm's body is bent and shaking, and it is restless. It spits out water, excretes soft feces, and prolapses its anus. Finally, it paralyzed and dies. Most of the silkworms killed in sleep do not shed their skin. Prevention and control measures: Do not pile up cotton, straw and other sundries in the silkworm room. Use chloramphenicol when diseased silkworms are found. V. Poisoning 1. Pesticide poisoning (1) Symptoms: acute, clustered, and sudden. When poisoned by trace amounts (some call it air poisoning), silkworms stop eating, crawl apart, spit out floating silk, become sluggish, or raise their front half and tremble. When poisoned by trace amounts in the fifth instar, silkworms cannot make cocoons when they are mature, and become naked pupae. Even if they make cocoons, they are deformed cocoons with thin skin. Severely poisoned silkworms vomit water, turn over, excrete loose feces, and die from rectal prolapse. The head of the corpse is protruding, the three segments of the chest are swollen, and the three segments of the tail are shrunken. (2) Prevention and control measures: Prevent pesticides from contaminating mulberry leaves. When poisoning is discovered, immediately remove the contaminated leaves and feed them with fresh, non-toxic leaves. Rinse seriously sick silkworms with cold water, place them in a ventilated place, and feed them with fresh leaves to revive them. 2. Waste gas poisoning (1) Symptoms: uneven development of the group, many fallen silkworms, protruding intersegmental membranes, ring-shaped or dot-shaped black lesions on the skin, and the intersegmental membranes of the skin are easily broken and bleeding, with normal blood color. The body color of the corpse is dirty brown and gradually shrinks. (2) Prevention and control measures: Mulberry gardens should be far away from factory areas. Mulberry leaves in contaminated areas should be tested for chlorine content before picking. Once poisoning occurs, feed them normal leaves immediately, wash the leaves or spray the mulberry leaf area with 1% lime water before picking the leaves.