Experts point out prevention and control of silkworms

The main measures are to do a good job of disinfection, to strengthen the breeding management of the original silkworm, to improve the quality of mulberry leaves, the appropriate density of silkworm eggs and other children. The scorpion fish, also known as scutellaria or cockroaches, is a type of silkworm in the late stage of the silkworm. The disease is more common in the production of silkworm eggs. Every year, every production has a different degree of occurrence. Among them, high-temperature production (3-5 productions) occurs more often, which brings about a certain degree of loss to the production of silkworm eggs. Now, based on some of our experimental investigations and some experiences in production, talk about the causes and prevention measures of the occurrence of chemical warts for reference. Symptoms and patterns of occurrence First, the occurrence of symptoms The body does not change color after death, is basically the same with the body color of health, from the appearance is not easy to see. On the second day after death, the corpus callosum began to soften, and it was easily squeezed with a finger and it was easy to flow out of the yellow fluid. After the first 3-4 days, all the tissues in the body were liquefied, leaving only the clams in the crust, and the tissue fluid was milky yellow without odor. Second, the law of occurrence In terms of the degree of occurrence of silkworms, the general occurrence of head-building was less, and the second-generation was gradually increased. The incidence of three to five constructions was the highest, and it was relatively reduced after six creations. Judging from the onset time of the corpus callosum, it usually starts from the first 2-3 days after pupation, peaks on the 4-7th day, and stops after the compound eyes turn dark. Pathogens and Infection Phase I. Pathogens There have been two different views in the past. Some experts believe that the larvae are caused by infection with nuclear polyhedrosis virus. However, some experts believe that nuclear polyhedrosis virus can only cause silkworm Disease, it is impossible to liquefy carcass tissue. In order to clarify the pathogens of the phlebotoctonosis, we used five phlegm-reducing phlegm and dilute it with 50 ml of cold boiled water, and then added 20 healthy candied larvae on the second day of the fifth instar. At the same time with cold boiled water add 20 cane as a control area. The results of the two feeding trials were exactly the same. All the 100% of body fluid type pyogenic lesions were found in the area before adding the food and water leeches to the mature silkworm, but there was no disease in the control area. It can be seen that the pathogen that caused the phlebotoroidosis is the body cavity type pyogenic polyhedrosis virus. Secondly, during the infection period, we used 15-20 body cavity pus juice diluted with 500 ml of cold boiled water and sprayed on mulberry leaves. The 5th instar silkworm was tested daily for food poisoning, and cold water was used as a control area. The results of the trial investigation showed that the peak of the onset of attack on the first day of 5th instar occurred before the mature silkworm; the onset of attack on the 5th instar of the 2nd to 3rd day occurred after the upper cluster and before the pupation; In the fifth to the sixth day of attack, the peak of onset occurred after the phlegm and before the compound eye darkened. No disease in the control area. It can be seen that the stage of larval infection is mainly caused by the polyhedra virus that infects the body cavity type pyogenic pyosis in the late 5th instar. However, some experts believe that it is also possible that 3-4 years of age are infected with the virus. Since silkworms have good conditions, they do not have the disease until the flood season. There is no such possibility and it needs to be further proofed in the future. The pathogenic factors First, the pathogenic factors All infectious diseases, silkworm, tick disease must be the presence of bacteria and infection, no pathogenic bacteria and the existence of infection is impossible. Insufficiency of disinfection, the existence of septic virus in Jamsil and silkworms, or lax disease prevention, brings the external virus into the house, and causes the outbreak of silkworm infection. This is the main factor causing the occurrence of pyogenic disease and later death. Second, the environmental factors Environmental factors are mainly temperature and humidity, high temperature and humidity, stenosis climate environment, in particular more than 30 °C high temperature and hot and humid weather on the silkworm stage (especially the 5th instar silkworm), the upper cluster and the previous flood season Large, weakening the physique and resistance to disease of silkworms and cockroaches, so the climate environment with high temperature, humidity, and smouldering is one of the important factors causing the occurrence of blisters. According to the production survey three to five seasons of high temperature and humidity, the occurrence rate of chemical warts is generally not lower than 5%-10%, and individual batches are as high as 30%-50%. Third, leaf quality factors silkworm stage, especially the large silkworm after the late phase of the partial application of nitrogen fertilizer over the mulberry leaves and immature leaves, wet leaves, water leaves and old tender and uneven and lack of sunshine and other bad mulberry leaves, but also lead to Another important factor in the occurrence of leeches. Because the silkworms eat these mulberry leaves with poor nutrition and high moisture, they directly affect the nutritional physiology and water imbalance of silkworms and cockroaches, and are not conducive to the improvement of the body and vitality of silkworms and cockroaches, making the silkworm body weak and becoming a cause of silkworm disease. . According to past production surveys, the batches of mulberry harvested were fertilized within 3 to 4 days after mulberry extraction, fertilized for 25 days per acre, and urea was applied at a rate of 7.5-10 kilograms per acre. Per mus of 15-20 kilograms of urea, the rate of water phlegm is 4%-5%; 25-30 kilograms per acre, water phlegm rate is 18%-25%. Application of 35-40 kg per acre, the rate of water stagnation rate of 32% -41%. At the same time, the silkworm stage, especially the large silkworm, has lately eaten mulberry leaves with excessive young leaves, wet leaves, water leaves, and long-term sunlight. The occurrence rate of chemical warts is the highest. Although no detailed investigations have been made, it is estimated that not less than 40%. -50%. Fourth, feeding factors Feeding patterns and feeding methods have a great impact on the occurrence of silkworm and late blisters. For example, for ground education, the effect of using mulberry sage and leaf mulberry culture is quite different. According to the survey, at the same time in mid-June, the same ants were bred in the same group and the same group was bred. The same mulberry land, the technical treatment is basically the same. However, the silkworm larvae of the mulberry sorghum were well developed. There was no pu? However, on the third day of the 5th instar, there was a large number of outbreaks on the 5th and 6th days. What are the reasons? According to our analysis, because of the mulberry ground cultivation. After the silkworm walks, the mulberry leaf stacks the mulberry leaf, the silkworm is difficult to eat through the slag, plus the silkworm seat is not ventilated, the mulberry leaf and the silkworm cocoon are mixed together, resulting in the fever of the silkworm seat, the surface of the silkworm seat is steamed with heat, so the temperature of the silkworm seat is high, Humidity. One day before we cooked the silkworm, we measured the temperature of the silkworm, and the ground temperature of the branches and branches was basically the same. The temperature was almost the same, with a difference of only 1°C. However, the temperature of the ground culture of leaf mulberry was higher. The bottom layer of the silkworm was 5°C higher than that of the cypress ground, the middle layer was 11°C high, and the surface height was 4°C. The clams surveyed the incidence of blisters in the flood season up to 50%-60%. Prevention and Control Measures I. Do a good job of disinfection and disease prevention to prevent the spread of germs. Based on the routine disinfection and disease prevention of breeding silkworms, it is necessary to strengthen the work of disinfection and disease prevention during the silkworm stage and breeding season. In particular, it is necessary to do a good job of disinfection and disease prevention in the 5th instar silkworm body and silkworms, so as to prevent repeated cross infection of pathogens. In production, we conducted such a test investigation: in the case of severe pyogenic disease in the 5th instar silkworm stage, fresh silk is used for disinfection of silkworm body and silkworm pods 5 times a day (ie, each lime sterilized before mulberry leaves). The incidence of blisters is only 2%-2.5%; the blisters are sterilized twice a day (once in the afternoon and once in the afternoon) and the blisters incidence rate is 10% to 12%; in the absence of disinfection, the blisters incidence is as high as 40% to 50%. Therefore, the strengthening of silkworm plots, silkworms, and the surrounding environment, as well as the sterilization and disease prevention of silkworms and silkworms, are important measures to prevent the occurrence of chemical warts. Second, do a good job in regulating the temperature and humidity during the silkworm stage and breeding season. The environment with high temperature, high humidity, and smolderiness has a great influence on the large silkworm stage, the upper cluster stage, and the previous flood season. Therefore, the large silkworm room, the upper cluster room, and the seedling protection room should be promptly provided with ventilation, cooling, and temperature reduction. Third, strengthen the technical management of all aspects of the breeding of silkworms. Raising the level of rearing techniques, making sure that fine tuberculosis, good mulberry and satiety, and strengthening the larvae's constitution are very important for the prevention of bacterial infections and the occurrence of silkworm diseases. Tests have shown that silkworms are robust and infected with 10,000 germs will not cause or reduce the incidence; silkworms will be weak and infecting a pathogen will cause the disease. Fourth, strengthen the management of raw silkworm mulberry fields and improve the quality of mulberry leaves. The original silkworm mulberry garden should be given more organic fertilizer and phosphorus and potassium fertilizers, less chemical nitrogen fertilizer, improve the quality of mulberry leaves. Satisfy physiological and nutritional needs of the silkworm body and enhance the resistance of silkworm to disease resistance. In the harvesting type, it is recommended to keep large tree tails and try to use mulberry branches as far as possible, and to strictly control the maturity of mulberry leaves. Leaf mulberry should be harvested once every 25 days, and mulberry branches should be harvested once every 50-55 days. Before harvesting, it must be topped 5-6 days in advance to promote full maturity of the parietal lobe. The silkworm period, especially in the later period of silkworm silkworms, must not eat young leaves, wet leaves, water leaves, fermented leaves, and mulberry leaves that are not uniform in the old and tender and lack of sunshine, and try to reduce the precipitating factors of the occurrence of phlegm. Fifth, the density of silkworm silkworm eggs should be appropriate to prevent the silkworm head from being too sparse or too dense. Bombyx was too sparse, and the food could not pass slag. The humidity in silkworms was large. The silkworms used dense silkworms to catch each other, causing wound infection. Tests have shown that the incidence of wound infection is 18%-20% higher than the frequency of infectious leeches. At the same time, in the early stage of cutting (ie, the tenderness period), it is necessary to exercise lightly to cut the fleas, divide males and females, and avoid falling into the larvae of the larvae to reduce wound infection. Six, we must observe the development of the situation. Weed out small and weak silkworms in time, especially when silkworm worms are found to be cleared in time, so as to prevent repeated infections of silkworms and the spread of silkworm diseases.

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