Rearing of Grown Mulberry Silkworm

In the production of sericulture, the 4th to 5th instar silkworms are generally called large silkworms or strong silkworms. Large silkworms are different from small silkworms in morphological and physiological characteristics, and have different requirements for breeding environment and nutritional conditions. Therefore, the feeding patterns and technical measures adopted have also changed accordingly.

The body surface area per unit weight of the large silkworm is relatively smaller than that of the small silkworm; the waxy layer of the skin is thicker than that of the small silkworm; the ratio of the valve to the body is relatively small; therefore, the water in the body is difficult to disperse, and the body temperature is likely to rise, generally about 0.5℃ higher than the temperature. . Large silkworms have weaker resistance to high temperature, humidity and sultry heat than small silkworms and are prone to disease. Therefore, the silkworm stage requires lower temperature, dry environment and proper airflow. The large silk glands grow rapidly, especially in the middle and late 5th instar. The weight of silk glands at 4th instar is more than 6 times that of 3rd instar, and about 40 times for 5th instar compared to 4th instar. When the 5th instar grows extremely, it is 160,000 times larger than that of silkworm. In order to meet the growth and development of silk glands and the need to synthesize a large amount of silk material, mulberry leaves that are rich in protein, less water, and more carbohydrates should be given and fully fed. The large amount of mulberry eaten is large, and the amount of mulberry used is 95 to 96% of the amount of mulberry used for the whole age, especially at the 5th instar, about 84 to 86% of the amount of mulberry used for the whole age, due to the amount of mulberry, the amount of residual mulberry and the discharge The amount of manure is large, and the breathing rate is also large. The indoor moisture and carbon dioxide increase, forming an environment of high humidity and air pollution. However, the gas exchange of large silkworms is more difficult than that of small silkworms, and the resistance to carbon dioxide is weak. Silkworms need more freshness. Therefore, it is necessary to strengthen ventilation to prevent the silkworm body from becoming weak due to obstruction of breathing. Although large silkworms are less resistant to toxic gases such as carbon monoxide and sulfur dioxide and pesticides, silkworms are stronger, but exposure to these toxic substances will still affect the yield and quality of silkworm cocoons. Although the resistance of large silkworms to pathogens is greatly enhanced, it is often caused by the accumulation of small amounts of infection at the small silkworm and the 4th instar to cause the outbreak of silkworm disease at the 5th instar. Therefore, the large silkworm must be strictly disinfected and disease-prevented, and the diseased silkworms must be isolated and eliminated to ensure Silkworms are safe.

The silkworm stage is a period when nutrients are accumulated and the silk glands are extremely developed. Attention should be paid to the following aspects in silkworm rearing.

1. The breeding temperature is 24-25℃ for 4th instar and 23.5-24.5℃ for 5th instar. The breeding humidity is 70~75% for 4th instar and 65~70% for 5th instar. Try to avoid low temperatures below 20°C and high temperatures above 30°C. To strengthen ventilation.
2. According to the temperature, the leaves and whole buds are generally given to mulberries 4-6 times a day, and mulberries are given 2 to 3 times a day.
3. Do a good job of disinfection and disease prevention. Disinfect the silkworms of silkworms before rearing, and use anti-stiff powder or lime powder to disinfect the sacs of silkworms. For non-infectious polymorphic myiasis, you can use “killing silkworm flies” to add food or body spray 2～4 For prevention and control.

The breeding methods of large silkworms include full bud breeding, mulberry breeding, ground sericulture and outdoor breeding. They should be adopted according to local conditions according to the sericulture season, sericulture technology, equipment and labor.