A Detailed Explanation of Autumn Silkworm Rearing Techniques and Feeding Management Key Points

I. Characteristics of the autumn silkworm period. In our city, mulberry trees are mostly pruned in the spring with the "even-branch" style of pruning, so spring leaf yield is low while autumn leaf yield is high, providing ample feed for rearing autumn silkworms. At the same time, temperatures are higher in the early stage and lower in the later stage, which suits the physiological requirements of the silkworm. Therefore, according to the climatic characteristics of the silkworm period, corresponding technical measures should be adopted to rear autumn silkworms well and improve economic returns.

II. Autumn silkworm rearing techniques (1) Strengthen fertilizer and water management in the mulberry garden to improve mulberry leaf quality: For autumn mulberry garden management, the focus should be on applying autumn fertilizer well and controlling the 4th—5th generation of mulberry pyralid, so as to improve the yield and quality of autumn leaves. Specifically, do the following work well: First, before the end of August, apply 40-50 kg of urea plus 10 kg of potassium chloride per mu, and mix it into the soil together with mulberry garden weeding. Sericulturists with the means to do so may spread pig and sheep waste or rice straw or chicken and duck waste over the mulberry ground to help the mulberry garden retain moisture and fertilizer, so that the mulberry trees grow vigorously. Second, after more than a week of high-temperature, sunny and hot weather, drought-relief work should be carried out in the mulberry garden. Third, do a good job of pest control in the mulberry garden during the autumn period. (2) Strict disinfection and disease prevention: Silkworm rooms and silkworm tools must be strictly disinfected to eliminate sources of disease. The main diseases during the autumn silkworm period are flacherie and white muscardine, and fresh lime powder has a strong killing effect on flacherie virus and white muscardine. In recent years, flacherie and white muscardine have rarely occurred in autumn silkworm rearing, which is directly related to the frequent use of lime powder. The method is to sprinkle fresh lime powder on the silkworm body and silkworm seat before feeding mulberry leaves, and then feed the leaves. Fresh lime powder should also be appropriately sprinkled around the silkworm room. (3) Strictly protect silkworm eggs and collect newly hatched silkworms at the right time. During the autumn silkworm period, temperatures are relatively high, so silkworm eggs must be protected from high temperatures, direct sunlight and rain during transport. After being transported back, they should be kept in a spacious, cool silkworm room, with good ventilation, and incubated at natural temperature. The time for collecting newly hatched autumn silkworms is earlier than for spring silkworms, and it is generally required to finish collecting the newly hatched silkworms before 9 a.m. (4) Careful rearing and full feeding with good leaves. In autumn there is more rain and moderate light, and leaf quality is relatively good, so work such as picking, transporting and storing mulberry leaves should be done well. Leaves should be picked in the morning after the dew has dried and after 4 p.m., and not during the high temperatures at noon. According to the weather forecast, more leaves should be picked appropriately before rain to avoid letting the silkworms eat wet leaves. The mulberry leaves picked back should be stored in a cool, humid place to prevent heating and air-drying. Young silkworms are reared under plastic film covering, with mulberry leaves given 4 times a day; older silkworms are reared conventionally, with mulberry leaves given 4-5 times a day. During the young silkworm stage, appropriately mature leaves are selected; during the older silkworm stage, the mulberry leaves are kept fresh, and withered leaves, heat-damaged leaves and leaves with pests and diseases are not fed. Work such as expanding the rearing bed and removing excrement should also be done in a timely manner. (5) Adjust temperature and humidity well. 1. Temperature adjustment: Autumn silkworms generally hatch and are collected in mid-to-late July or early August, and finish in mid-to-late August. Throughout the silkworm period, heating is almost unnecessary; in special years or on rainy days, when the target temperature cannot be reached in the later stage, appropriate supplementary heating is needed. 2. Humidity: The entire autumn silkworm period is humid, and dehumidification is an important task during this period. Excrement should be removed frequently, and ventilation should be done well. Before the first feeding of mulberry leaves each evening, evenly sprinkle a layer of quicklime powder on the silkworm body and silkworm seat to absorb moisture and disinfect the silkworm body, keeping the silkworm seat dry and hygienic and preventing silkworm diseases. (6) Disinfection and disease prevention. Because the silkworm variety reared for mid-autumn silkworms is a spring-use variety, its disease resistance is relatively weak, so disease prevention for mid-autumn silkworms is even more important. 1. Strengthen disinfection of the silkworm body and silkworm seat. At the start of each instar during the older silkworm stage, use bleaching powder anti-muscardine powder (lime powder: bleaching powder = 8:1) to disinfect the silkworm body. During the instar, on sunny days use fresh lime powder once each morning or evening; on rainy days use it once in the morning and once in the evening, until the silkworms are seen to be mature. The amount used must be sufficient and even to ensure the disinfection effect. In particular, in places where it has often occurred in previous years, fresh lime powder must be used sufficiently and well. 2. Correct use of trichlorfon for silkworms. Change the original method of use. Because the body-spraying method has a good effect on killing eggs, and the feed-additive method has a good effect on killing maggots inside the silkworm body, the use of trichlorfon for silkworms must combine body spraying with feed addition, and feed addition must ensure the medication time, using it continuously for one course of treatment (3-4 times). Before mounting on the cocooning frame, body spraying must be carried out once. 3. Daily disease-prevention and hygiene work. Wash hands before feeding mulberry leaves and after removing excrement; step on lime when entering and leaving the silkworm room; during excrement removal, minimize dust flying. Tools for transporting silkworm excrement must be strictly separated from tools for transporting mulberry leaves. Silkworm excrement must not be dumped casually beside the silkworm room, but should be dumped in a silkworm excrement pit far from the silkworm room and covered with plastic film. After excrement removal, disinfect the floor of the silkworm room once with 0.3% effective chlorine bleaching powder water; the leaf storage room and leaf-picking tools should be disinfected once every two days with 0.3~0.5% effective chlorine bleaching powder water. 4. Observe silkworm development, detect silkworm diseases in time, and strengthen isolation. Frequently observe silkworm development. When diseased silkworms are found, pick them out promptly and put them into a lime container, or put them into a plastic bag containing lime and bury them deeply. Hands that have picked up diseased silkworms must be washed clean before feeding normal silkworms.