Optimizing Mulberry Silkworm Rearing During Summer and Autumn

Summer and autumn silkworm rearing presents unique challenges and opportunities compared to spring rearing due to variable environmental conditions and mulberry leaf quality. Understanding these factors is crucial for successful silk production during these seasons.

1. The Diverse Landscape of Summer and Autumn Rearing

Summer and autumn silkworm rearing encompasses a series of cycles from late June to mid-October in regions like the Yangtze River basin. This period is typically divided into:

• Summer Silkworms: Reared from June to July.
• Early Autumn Silkworms: Reared from July to August.
• Mid-Autumn Silkworms: Reared from August to September.
• Late Autumn Silkworms: Reared from September to October.

The suitability of each cycle varies geographically, with some regions experiencing high temperatures and humidity while others encounter drier, cooler conditions. For example, Yunnan, Shanxi, and Hebei have favorable conditions for mid-autumn silkworms, whereas areas like Jiangsu and Zhejiang face more challenges. This variation necessitates careful selection of rearing periods based on local climate and resources.

2. Unique Challenges of Mulberry Leaves in Summer and Autumn

Unlike the synchronized growth of mulberry leaves and silkworms in spring, summer and autumn present complexities:

These seasonal variations require diligent leaf selection and proper storage to ensure adequate nutrition for silkworms.

3. Increased Disease and Pest Pressure

The combination of high temperatures and humidity during summer and autumn creates an environment conducive to the rapid multiplication of pathogenic microorganisms. The increased use of rearing facilities also means a higher risk of disease transmission. Moreover, mulberry gardens often experience more pest and disease activity during this period, which can be transferred to silkworms or necessitate the use of pesticides, thus increasing the potential for silkworm poisoning.

4. Strategic Rearing Practices

Effective summer and autumn silkworm rearing relies on strategic adjustments:

4.1. Strategic Timing

Sericulture periods must be aligned with local climate patterns, mulberry leaf growth, and available resources. In Jiangsu and Zhejiang, for instance, the summer silkworm benefits from thinning bud leaves and the base leaves of autumn shoots. The timing for autumn silkworms is categorized into early, mid, and late, each requiring tailored leaf management practices. Conversely, regions with extended summers, like Guangdong, support multiple rearing cycles annually, leveraging the continuous growth of mulberry trees.

4.2. Breed Selection

Choosing the right silkworm species is paramount. Early autumn silkworms, for example, need hardy breeds with high stress and disease resistance. In contrast, mid-to-late autumn silkworms can benefit from species known for superior cocoon quality and silk yield.

4.3. Meticulous Management

• Hygiene: Implement stringent disinfection protocols before, during, and after each rearing cycle, isolate diseased silkworms, and disinfect all equipment to prevent disease spread.
• Early-Stage Care: Adhere to the “three specializations and one remote” system for young silkworms, ensuring separate rooms, tools, and personnel, as well as distance from older silkworm areas. Harvest silkworm eggs in the evening or early morning to prevent heat stress and fatigue.
• Mulberry Leaf Management: Harvest mulberry leaves early in the morning, when they are cool and dew-covered, and focus on obtaining 70% of the daily leaf consumption during that session and harvest the remaining portion in the evening. Choose tender leaves for young silkworms and greener leaves for older ones. Store leaves properly in cool, humid places and only pick what is needed daily.
• Feeding and Environment Control: Employ 3–4 feedings per day for young silkworms, frequently monitoring and adjusting temperature and humidity. Reduce feed volume during high temperatures and open areas less to reduce heat. Use thin, frequent feedings for older silkworms during sultry weather and wet leaves during hot, dry periods. Ensure there is adequate space for silkworms, frequently changing bedding and raising the silkworms in multiple layers. During late autumn, pay close attention to maintaining temperatures above 20℃.

Conclusion

Successfully rearing silkworms during summer and autumn requires a keen understanding of the environmental fluctuations, leaf quality changes, and disease pressures unique to these seasons. By strategically scheduling rearing cycles, selecting suitable breeds, and employing meticulous management practices, sericulturists can optimize their yields and ensure the high quality of their silk production.