Varietal Traits
Jingsong × Haoyue is a spring-season variety with high silk yield and four instars. The egg color is grayish-green in the reciprocal cross and purplish-brown in the reverse cross; the eggshell is pale yellow in the reciprocal cross and white in the reverse cross. The larval body color is dark brown, with a tendency to disperse. During the vigorous-mature stage, the larvae exhibit phototaxis and a tendency to aggregate; their body color is bluish-white with widespread spots. The mature larvae are pale rice-red in color. They spin upper-layer cocoons that are uniform in shape and white in color, with moderate shrinkage and wrinkling. The cocoon shell percentage is 24–25%, the cocoon filament length is 1,341 meters, the reeled filament length is 1,105 meters, the filament fineness is 2.5 denier, the reeling recovery rate is 82.4%, and the cleanliness score is 94.
Key Points of Rearing Techniques
1. Strict disinfection to prevent disease: Thoroughly wash and disinfect the silkworm rearing rooms and equipment before starting rearing; establish a dedicated mulberry-storage room; at each instar, alternate every other day between using “Silkworm Disease Prevention No. 1” and fresh lime powder for isolation and disinfection of the rearing trays; and fumigate the rearing rooms with smoke agents during the dormancy period.
2. Hatching induction standards: For embryos of grades B3 to D2, maintain a hatching temperature of 22–23°C; for embryos of grades D3 to F5, maintain 25–26°C, with a diurnal temperature fluctuation of 1.5–2°C; the hatching induction period is approximately 11 days.
3. Temperature and humidity standards: For the 1st–2nd instars, maintain a temperature of 27–28°C with a dry–wet temperature difference of 1–1.5°C; for the 3rd instar, maintain a temperature of 25–26°C with a dry–wet temperature difference of 1.5–2°C; for the 4th–5th instars, maintain a temperature of 23–24°C with a dry–wet temperature difference of 3°C. During hot, humid seasons, the dry–wet temperature difference should be slightly larger, by 1–2°C.
4. Medicated Feeding: Administer an antibiotic supplement once each during the 3rd to 5th instar, the peak feeding period, and the pre-pupal stage.
Precautions
1. Conduct dark treatment at the appropriate time, strictly prevent ant-collecting bags from being stacked and steamed, and avoid overheating that could damage the inoculum.
2. During the egg-receiving and feeding stages, the mulberry leaves should be moderately mature but tender. In the young-caterpillar stage, due to their phototaxis and tendency to cluster, it is important to ensure even lighting and to distribute the trays and rearing frames uniformly so that the larvae are evenly spaced. The fifth-instar peak-feeding period tends to occur later; typically, vigorous leaf consumption begins about four days after the fifth instar. At this stage, provide well-matured but slightly older mulberry leaves to allow the larvae to feed to full satiety.
3. Properly store mulberry leaves; do not cover the mulberry leaves with plastic film, and avoid feeding them tender, wet, or sticky, deteriorated leaves to prevent bacterial infection, which can lead to increased numbers of fifth-instar diseased silkworms, silkworms that die in the cocoon cluster, and silkworms that fail to spin cocoons.
4. Avoid exposure to pesticides and tobacco, and protect against damage caused by rodents, ants, and other pests.
5. Mature silkworms produce copious amounts of urine, which accumulates rapidly in the rearing room upon transfer to the cocooning rack, accelerating cocoon formation. Therefore, it is essential to prepare the cocooning room and equipment in a timely manner to avoid being caught off guard and compromising the cocooning rate. When transferring mature silkworms to the rack, aim for slightly underripe stages, and pay close attention to the density and uniformity of the placement. This variety prefers to spin upper-layer cocoons. Within the rack, ensure effective moisture removal, even lighting, and protection from strong direct winds.
