Detailed Explanation of Key Technical Points for Disinfection and Disease Prevention in Silkworm Rearing

With the Western Development Strategy, the state began implementing the "East Mulberry Moved West" plan. In many places in Yunnan Province, as part of a new round of industrial restructuring, the sericulture industry is being given key support as a distinctive industry for increasing farmers' income and helping them become prosperous. However, during the @#@250@#@ process, outbreaks of silkworm diseases caused by inadequate disinfection or improper methods often leave mulberry-growing and silkworm-rearing farmers with no cocoon harvest at all and with heavy economic losses. Thorough disinfection and disease prevention, and eliminating pathogen transmission, are the key measures for achieving high-quality and high-yield silkworm cocoons. The key technical points are as follows.

1. Disinfection and disease prevention of silkworm rearing houses. Create a pollution-free rearing environment through careful sweeping, washing, sun exposure, and chemical disinfection. First, thoroughly sweep and wash the silkworm room and its surroundings. If the silkworm room has a mud floor, scrape off a 1-2 cm thick layer of surface soil, and whitewash the gray ceiling with lime powder. Close the doors and windows, and spray and disinfect with 1% bleaching powder solution, using 25 kg of 1% bleaching powder solution per 100 sq m, striving to spray thoroughly without leaving any dead corners, and keep it moist for more than half an hour. Wash silkworm tools in running water, dry them in the sun, and place them into a disinfection tank containing bleaching powder solution with 1% effective chlorine for immersion disinfection. After disinfection, do not immediately dry the silkworm tools in the sun; place them in a disinfected silkworm room and pile them up tightly for 12 hours, then take them outside for sun exposure. Bleaching powder is one of the most widely used disinfectants in the process of silkworm rearing, and it has a strong killing effect on many pathogens such as viruses, bacteria, fungi, and protozoa. Bleaching powder disinfection should preferably be carried out on cloudy days or in the morning or evening. The disinfection site should be protected from direct sunlight and strong winds. The disinfectant solution should be clarified and can be prepared 1-2 hours before disinfection; it should not be prepared too early, otherwise it will lose effectiveness. Before disinfection, first moisten the walls and silkworm tools with clean water. Bleaching powder is a white powder; it should be stored sealed in a dark and dry place.

2. Disinfection and disease prevention during silkworm rearing. During the process of silkworm rearing, silkworm eggs or the silkworms themselves may carry diseases and transmit them, and pathogens in the surrounding environment may also enter the silkworm room through various routes. A single disinfection before silkworm rearing alone cannot ensure that the silkworm room and silkworms are disease-free, so disinfection and disease prevention work during silkworm rearing must also be strengthened.

(1) Isolate and eliminate diseased and weak silkworms. The excrement of diseased silkworms contains a large number of pathogens, becoming the main source of infection in the silkworm rearing bed. Therefore, observe carefully at ordinary times. Before the silkworms molt, strictly carry out the work of sorting out the green silkworms and grouping them in batches. Isolate or eliminate silkworms with weak constitutions and delayed development, so as to eliminate opportunities for infection in the silkworm rearing bed.

(2) Disinfect the silkworm bodies and silkworm rearing bed. Newly hatched silkworms, newly molted silkworms of each instar, silkworms about to molt, and silkworms about to mature are the most susceptible to silkworm diseases. Therefore, when collecting newly hatched silkworms, before seeing them molt, before feeding after molting, and after seeing them mature, use No. 1 Disease Prevention Powder once each time (for newly hatched silkworms and 1st-2nd instar silkworms, use No. 1 Disease Prevention Powder for young silkworms; for 3rd instar to mature silkworms, use No. 1 Disease Prevention Powder for grown silkworms; the dosage is 20-25 grams per sq m for 1st instar silkworms, 30-35 grams for 2nd instar, 40-50 grams for 3rd instar, 50-60 grams for 4th instar, and 60-80 grams for 5th instar) for disinfection. Starting from the 3rd instar, scatter fresh lime powder once a day in the silkworm rearing bed. Summer and autumn are periods of high incidence of bacterial diseases. Starting from the 3rd instar, each instar must also be given 1-2 feedings of Canjunqing or chloramphenicol.

(3) Establish a disease prevention system. After each removal of sand, disinfect the silkworm room, silkworm tools, and surrounding environment with 0.5% effective chlorine bleaching powder solution or 2% fresh lime slurry. Rearing personnel must wash their hands before cutting mulberry leaves, before feeding mulberry leaves, or after removing sand, and must change shoes before entering the room or step on lime before entering the room. Handle silkworm excrement promptly, and put diseased silkworms and dead diseased silkworms into a disinfection vat.

3. Disinfection after the end of silkworm rearing. The end of the silkworm rearing period is a good opportunity for thorough disinfection. The silkworm room and silkworm tools can be promptly sprayed and disinfected once with bleaching powder solution with 1% effective chlorine or 2% fresh lime slurry, and then swept and washed to prevent the spread and transmission of pathogens. Garbage such as bedding paper, bedding straw, and straw mounts should be immediately cleared and burned. Square mounts and folded mounts that are to be reused should be stored in an empty room far away from the silkworm room after sun exposure, and should not be touched until the next silkworm rearing period when silkworms are mounted on the mounts. The above technical measures have a significant effect on killing pathogens and preventing silkworm diseases.