Characteristics of silkworm disease control

(1) A wide range of sources of infection

1. The source of infection in the process of sericulture: dead silkworm, pupa, moth and their diseased silkworm feces, silkworm sand, old cocoon and rotten cocoon are serious sources of infection of silkworm disease.

2. Cross-infection with wild insects, mulberry leaves contaminated by diseased field insects, insect carcasses and insect droppings are another source of infection of silkworm disease.

3. Pathogen accumulation and poison pollution in sericulture environment.

(2) due to poor feeding and management, silkworms are physically weak and prone to disease

1. Do not pay attention to disinfection, engage in carelessly; or only pay attention to spring silkworm disinfection, ignore summer and autumn silkworm disinfection; only pay attention to disinfection before sericulture, ignore disinfection in or after silkworm period; or only pay attention to disinfection and ignore disease prevention.

two。 Poor breeding and management, extensive sericulture. In the process of sericulture, we do not pay attention to the treatment of sleep, do not pay attention to raising green in batches, or artificially cause weak silkworms, such as uneven mulberry, weaken the physique of silkworms and are prone to disease. Some people are used to removing sand by hand and extensive operation, which can injure silkworms and increase their chances of suffering from nuclear polyhedrosis and septicaemia.

3. Sericulture facilities can not keep up, and poor planning often occurs in production, the proportion of silkworms is out of balance, or sericulture equipment is insufficient, and silkworms are too dense; silkworms are reared in the same room, and silkworm tools are mixed; or mulberry leaves are stored in the silkworm chamber; or the sericulture period is too dense, there is not enough time for cleaning and disinfection between sericulture batches.

(3) the poor quality of leaves leads to physical weakness or poisoning of silkworms and reduces disease resistance.

1. Poor management of mulberry garden, or partial application of nitrogen fertilizer, resulting in low leaf quality.

2. Fat and abundant water sufficient mulberry garden, or summer mulberry tree grows only, the leaf quality is not mature enough, the water content is too high, the sugar content and protein are too low, the silkworm eats for a long time, the physique is weak and sick.

3. Mulberry trees are polluted by air, which results in chronic poisoning after eating silkworms, poisoning death in severe cases, dysplasia in mild cases and low disease resistance.

(4) poor quality or improper use of sericulture drugs

(5) adverse climatic conditions often become an important inducement of some major silkworm diseases. The temperature range for normal growth of silkworm is 20-30 ℃. The temperature below 15 ℃ and above 30 ℃ is excessive temperature, which is easy to induce silkworm disease. The optimum temperature of 4-5 years old is 22-24 ℃, and the relative humidity is 70-75%. In production practice, the temperature in summer and autumn is often as high as 33-35 ℃, which affects the physiological function and disease resistance of silkworm. The large silkworm eats more mulberry, accumulates more water in the body, the body surface area is relatively less than the young silkworm, and it is difficult to dissipate heat. Therefore, when the big silkworm meets high temperature, it is more likely to induce all kinds of silkworm diseases, such as cytoplasmic polyhedrosis, dense nuclear disease, viral softening disease and so on. The high temperature and humidity environment is more conducive to the reproduction of some pathogenic microorganisms, resulting in an increase in the density of environmental pathogens and increasing the chance of infection of silkworms.