Causes and Control Methods of Silkworm White Muscardine

Silkworm white muscardine is caused by Beauveria bassiana entering the silkworm body through the skin. The route of infection is contact transmission. After the silkworm dies, the body is first soft and then hard, covered entirely with white conidia, and is called a "white muscardine silkworm." Beauveria bassiana prefers moisture and fears dryness; in humid places and rainy seasons, silkworms are very prone to the disease. If disinfection and disease prevention work is neglected during the silkworm rearing period, it will cause a major outbreak of white muscardine.

Causes of silkworm white muscardine

① The rearing rooms and rearing tools for cooperative rearing of young silkworms were not thoroughly disinfected according to the prescribed standards, and the residual amount of Beauveria bassiana was high.

② There were no dedicated rearing rooms for rearing large and young silkworms separately; young silkworms were reared in the inner room and large silkworms in the outer room, or large silkworms were reared in the front house and young silkworms in the back house, causing Beauveria bassiana to spread to the young silkworms and cause disease.

③ Diseased and dead silkworms with white muscardine were not collected and treated centrally, expanding the spread range of Beauveria bassiana.

④ The humidity in the rearing room was high, and silkworm excrement was removed too infrequently.

⑤ The rearing rooms and rearing tools were disinfected too seldom, and too little medication was applied to the silkworm bodies and rearing beds.

⑥ Insect control work in the mulberry field was belittled; the density of Lepidoptera pests in the mulberry field was high, and after white muscardine occurred, it contaminated the mulberry leaves and the surrounding environment, causing infection and disease in the silkworms.

Control of silkworm white muscardine

① Strictly implement the separate rearing system of "dedicated rooms, dedicated tools, dedicated use, and young silkworm rooms far from large silkworm rooms."

② Rearing rooms, rearing tools, and the surrounding environment must be strictly disinfected according to standards; a bleaching powder solution containing 1% effective chlorine or a 1000-fold dilution of Fangjiangling No. 2 can be used for comprehensive spraying.

③ Economically use anti-muscardine agents to disinfect silkworm bodies and rearing beds; when the silkworms rise at each instar, anti-muscardine powder should especially be sprinkled for disinfection. After large silkworms develop muscardine, use a 1500-fold dilution of "402" aqueous solution for body spraying for 3 consecutive days, then spray once every other day, which can control the spread of white muscardine.

④ Diseased and dead silkworms should be picked out promptly and placed in a disinfection vat to be burned centrally; they must never be discarded or thrown away randomly, and even more must not be collected, sun-dried, and sold. Silkworm excrement should be collected and composted centrally, and must never be dumped or placed randomly.

⑤ Use smoking materials such as sawdust and dry grass for smoke fumigation, close doors and windows, then open doors and windows after 1 hour to release the smoke; fumigate once a day, which can prevent the occurrence and spread of white muscardine.

⑥ Adjust the humidity in the rearing room well; when the indoor humidity is high on cloudy and rainy days, more drying materials such as lime and scorched chaff can be sprinkled; remove silkworm excrement frequently to keep the rearing room clean and hygienic.

⑦ Frequently carry out insect control in the mulberry field to control the population density of insects in the wild and prevent cross-infection and disease.

⑧ After @#@250@#@ ends, rearing tools, silkworm mounts, and the inside and outside of the rearing room must all be comprehensively and thoroughly disinfected with bleaching powder containing 1% effective chlorine, leaving no blind spots.