CATDOLL : CATDOLL: What key technical measures should be mastered in greenhouse silkworm farming?

What key technical measures should be mastered in greenhouse silkworm farming?

Greenhouse breeding is generally carried out during the adult silkworm period. Adult silkworms have weak resistance to high temperature, high humidity and stuffiness. They eat a lot of mulberry leaves, so greenhouse breeding should strengthen ventilation and avoid long-term exposure to high temperature, high humidity and stuffiness. Especially in a special environment like a plastic greenhouse, breeding work should focus on key measures.

(1) Strengthen the regulation of the microenvironment in the greenhouse

Among them, temperature and humidity regulation is the key and difficulty of greenhouse silkworm rearing technology. Measures should be taken in time according to the actual weather conditions to keep silkworms in a relatively suitable temperature range of 20-28℃ (not less than 22℃ for the fourth age) for normal growth. After sunrise on a sunny day, around 9 am, the temperature in the shed reaches the appropriate temperature. At this time, the film at both ends or all around should be opened to let in air. If the temperature is too high, water can be sprinkled on the sunshade net on the roof or the straw curtain to cool down. Around 5 pm, when the temperature in the shed drops to the appropriate temperature, the film of the shed should be gradually lowered and covered with straw curtains for heat preservation. If the outside temperature is stable above 20℃, air can be let in day and night. When the temperature is too low at night or on rainy days and in the late autumn silkworm period, efforts should be made to heat it. When the humidity in the shed is too high, the film should be lifted to drain moisture and more dry materials should be used. When it is rainy continuously, straw can be used for fumigation once a day for 1 hour each time.

(2) Strictly carry out disinfection and disease prevention work in the greenhouse

Disinfection of silkworm bodies and silkworm seats after entering the shed: Sprinkle fresh lime powder once a day; sprinkle anti-bacterial powder No. 1 for large silkworm disease prevention once every other day (no need to sprinkle lime powder when sprinkling anti-bacterial powder). Sprinkle once a day when bacterium is found; on the third day of the fourth instar and the second, fourth, and sixth days of the fifth instar, add 500 times liquid of silkworm fly killer to the feed or spray with 300 times liquid; from the start of raising the silkworms, add 500 times liquid of chloramphenicol to the feed on odd days.

(3) Disinfection of internal and external environment

A lime pit is set up at the entrance of the greenhouse, and people step on the lime to enter the greenhouse; 0.5% effective chlorine bleaching powder is sprayed every day. At the same time, regular inspections are also required to prevent damage from toads, rats, snakes, ants, etc.

How to properly adjust the humidity in the silkworm greenhouse?

When humidity increases, it is difficult for silkworms to evaporate moisture, their body temperature rises, their breathing increases, their pulse speeds up, and excessive humidity causes silkworms to become enlarged and their health declines. If high humidity is combined with high temperature, the harm of high temperature to silkworms will be further increased; while lowering humidity can reduce the harmful effects of high temperature.

Generally, the suitable humidity for breeding is 80% to 90% at the first age, and then decreases by 5% to 6% with each age. By the fifth age, the relative humidity should be 60% to 70%.

In order to have a humidity environment in the greenhouse that is more suitable for the growth and development of silkworms, the air humidity and soil humidity in the plastic greenhouse should be controlled scientifically and reasonably.

(1) Greenhouse ventilation reduces humidity inside the greenhouse

The air humidity in the greenhouse is mainly regulated and controlled by natural ventilation. During the spring silkworm period and the late autumn silkworm period, the outside temperature may be low at night. At this time, ventilation and dehumidification often conflict with closing the greenhouse for insulation, that is, closing the greenhouse for insulation often increases the humidity in the greenhouse, while ventilation and dehumidification will reduce the greenhouse temperature. The contradiction between insulation and ventilation and dehumidification is mainly solved by the early and late ventilation time, the length and the size of the vents. In the low temperature stage, insulation is the main focus, and dehumidification is the auxiliary. Ventilation should be carried out late and the greenhouse should be closed early. If there are skirt windows, use the skirt windows for ventilation as much as possible. When ventilating with the vents on both sides of the greenhouse, it should be done on the leeward side, and ventilation should be done on the windward side only when the temperature in the greenhouse is too high. When the temperature is high, the temperature should be reduced and moisture should be removed. Ventilation should be carried out early, and strong winds should be blown until ventilation is carried out day and night.

(2) Control soil moisture

The air humidity in the greenhouse is related to the soil humidity. When the air humidity is too low, the ground humidity in the greenhouse is often low. Therefore, the air humidity can also be controlled by adjusting the ground humidity. The ground humidity is most simply and effectively adjusted by watering. The method can be determined according to the layout of the silkworm beds in the greenhouse. Before ventilation, less watering should be applied. After ventilation, the amount of watering should be gradually increased as the ventilation volume increases. When raising summer silkworms in the greenhouse, the temperature is high and the ventilation volume is increased. Special attention should be paid to increasing the ground humidity in the greenhouse to prevent the dryness in the greenhouse from accelerating the withering of mulberry leaves and affecting the growth and development of silkworms.

(3) Direct moisturizing of mulberry leaves

Mulberry leaves are often very easy to wither during the strong sunlight in the afternoon and in the hot season. At this time, increasing the humidity in the silkworm greenhouse can play a dual role of cooling down and keeping the mulberry leaves fresh.

When replenishing water with mulberry leaves, attention should be paid to the cleanliness of the water source and the reasonable amount of water replenished to avoid excessive water replenishment and pathogen contamination of mulberry leaves which may cause silkworm disease.