Crawfish crayfish have strong resistance to disease and are not easy to get sick in natural waters. With the increasing market demand, the yield per unit of production is also increasing, and the breeding density is becoming larger and larger. Improper management can easily lead to disease, and its disease is increasingly The trend of spread, especially viral diseases, has not yet been effectively treated. Treating shrimp disease should be based on the 16-character principle of early prevention without disease, early treatment with disease, prevention with prevention, and prevention and control. The following are some methods of prevention and treatment of common diseases of crawfish, as well as the points of attention in the breeding process:
First, fungal diseases
1. Pathogens and diseases of black shank disease: The disease is mainly caused by water pollution, and the crawfish pupa filaments are caused by fungal infection. Symptoms change from flesh to brown or dark brown until completely darkened, causing atrophy of the cockroach. Diseased shrimp tend to stay on shore and eventually die of breathlessness.
Prevention methods: 1 Keep the water body clean and the oxygen is sufficient. The water body regularly splashes lime with a certain concentration to adjust the water quality. 2 The diseased shrimp was soaked in 3%~5% of the salt per cubic meter of water for 2~3 times, every 3 minutes~5 minutes; or per cubic meter of water, splashed with 10 grams of methylene blue water.
2. Crawfish plague pathogens and conditions: The pathogen of crawfish plague is caused by the aastiosis of the genus Aphanomyces. The condition is that the diseased shrimp has yellow or brown spots on its surface. Fungal filaments can be found at the base of the appendages and the ocular stems. The pathogen invades the crawfish, attacks the central nervous system, and rapidly damages motor neurons. Shrimp is sluggish, the activity is greatly reduced or the activity is abnormal, and it is very easy to cause a large number of sick shrimps to die.
Control methods: Maintain fresh water and maintain normal water color and transparency. It is an effective method to control crawfish plague.
Second, bacterial diseases
1. Pathogens and diseases of rotten gill disease: The pathogen is filamentous bacteria. Symptoms are that the bacteria is attached to the diseased shrimp larvae and grows in large numbers, blocking blood flow in the sacral area and impeding breathing. Severe black silk and mildew caused death of diseased shrimp.
Control methods: 1 Regularly remove residual bait and dirt in the shrimp pond, inject new water, maintain a good water environment, maintain the health and safety of the breeding environment, and maintain the dissolved oxygen in the water body at more than 4 milligrams per liter to avoid water pollution. 2 With 0.5 grams of chlorine dioxide per cubic meter of water Quanchiposa, you can play a good therapeutic effect.
2, crustacean pathogens and conditions: The disease is caused by chitin-degrading bacterial infection. In the early stages of infection, dark spots appeared in the crustacea of ​​the diseased shrimp, and the edges of the diseased spots festered and appeared empty. In severe cases, larger or more empty holes cause internal infection and even death of the diseased shrimp.
Control methods: 1 When transporting and feeding shrimp, do not stack and injure the shrimp. 2 During feeding, the feed should be cast and evenly distributed to prevent the shrimp from competing for food or killing each other due to insufficient feed. 3 The disease occurs, with a total of 15 grams to 20 grams of water per kilogram of tea infusion soaked Quanchiposa. 4 The use of 5kg to 6kg of quicklime per 667m2, or the spillage of 0.5g of chlorine dioxide per cubic meter of water, can result in better treatment effects, but lime and chlorine dioxide cannot be used at the same time. .
3, tail disease.
Pathogens and Disorders: Caused by injury, mutual food, or bacterial infection by chitin. In the early stage of infection, the diseased shrimp has blisters on the tail, and the edge is festered, necrotic, or incomplete. As the disease progresses, the ulcer develops from the edge to the middle, and when the disease is severely infected, the entire tail of the diseased shrimp is festered and dropped.
Control methods: (1) Do not stack and injure shrimp when transporting and feeding shrimp. (2) During feed, the feed should be cast and fed in order to prevent shrimps from competing for food or killing due to insufficient feed. (3) In the case of this disease, each cubic meter of water is splashed with 15 grams to 20 grams of immersion liquor in the whole pool; or every 667 square meters of water is splashed with 5 to 6 kilograms of lime.
4. Bacterial enteritis pathogens and conditions: Mainly because of the consumption of unclean foods, or the damage of the digestive system caused by parasite parasitic damage caused by Aeromonas punctiform infection. In the early stages of infection, the diseased shrimp suffers from loss of appetite, followed by no food, and approaches shallow waters and shores. The digestive tract is swollen with hyperemia and there is a lot of pale yellow mucus. As the disease progresses, it will eventually die, and it will also cause other healthy shrimp infections. It is more aggressive and the consequences are more serious.
Control methods: (1) Strengthen feeding and management, make the pool water alkaline, adequate dissolved oxygen, strictly implement the "four elimination and four set" measures, in the summer to deepen the pool water, so that the water temperature changes less. (2) Each 667 square meters of water will be splashed with 5kg to 6kg of lime, or 0.5g per cubic meter of water.
Third, protozoan disease
1, ciliate pathogenesis and symptoms: ciliate disease pathogens are the most common poly-deed insects, tired worms and bell-shaped insects. Ciliates attach to the body surface, appendages, and tendons of shrimps, juveniles, larvae, and fertilized eggs. When attached in large numbers, ciliates impede shrimp breathing, swimming, activity, feeding, and clam shell function, affecting growth and development. In particular, when a large number of cockroaches are attached, the gas exchange of the cocoon wire is affected, and even the shrimp body is deprived of oxygen and suffocates. During the larvae's illness, the surface of the shrimp body is covered with a layer of white floc, resulting in weakening of the larvae's motility and affecting the development and metamorphosis of the larvae. The disease is more harmful to juvenile shrimp. Adult shrimp are mostly parasitized at low temperatures.
Control methods: 1 Thoroughly clear the pond, kill the pathogen in the pool, have a certain preventive effect on the disease. 2 Use 3% to 5% saline to dip, 3 days to 5 days for a course of treatment. 3 Iodine (quaternary ammonium salt content 50%) complexed with tetraalkyl quaternary ammonium salt. Quanchiposa at a concentration of 0.3 mg per liter. 4 Maintain a reasonable stocking density, pay attention to the sanitation of shrimp ponds, change new water frequently, and keep the water fresh.
2. Pathogens and diseases of polydenomiodosis: The pathogen is poly-decompression, and the symptoms are that the crawfish crayfish cannot be shelled successfully. The sick shrimps often die in the shelling process, and larvae and adult shrimps can occur, which is more harmful to juvenile shrimps. serious.
Control methods: (1) Thoroughly clear the pond and kill pathogens in the pond. (2) The disease can often be changed in large quantities, reducing the number of polyps in the pool water.
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