After the founding of the People's Republic of China, the People's Government attached great importance to sericulture production and formulated the policy of "active recovery and vigorous development". In order to develop sericulture science, Jiangsu Province established the Wuxi Experimental Ground. Cao Yisun was hired as a technician at the field, specializing in the prevention and control of silkworm diseases. He often goes deep into the sericulture areas of southern Jiangsu to conduct investigations and research, understand the problems existing in sericulture production and silkworm disease prevention, and teach disease prevention techniques. In 1951, the Wuxi Experimental Field, the Sericulture Department of the Jiangsu Academy of Agricultural Sciences, the Shanghai Cocoon and Silk Inspection Institute and other units merged to form the East China Sericulture Research Institute (now the Sericulture Research Institute of the Chinese Academy of Agricultural Sciences) in Zhenjiang City. Cao Yisun was appointed as a researcher, leader of the silkworm disease group, and director of the pathology research office, engaged in research on silkworm pathology. From then on, he had stable and superior working conditions and devoted himself to the scientific research of silkworm diseases.
Cao Yisun has always focused on applied technology and applied basic research. He often personally participated in experiments, collected first-hand information, and patiently helped young and middle-aged comrades. He had strict requirements on them and was persuasive, so that they could gradually grow into a new generation of silkworm disease experts. Under his leadership, the comrades of the Silkworm Disease Research Laboratory formed a very united team. They first conducted research on the solubility and infection patterns of pyogenic polyhedrons, and measured the resistance of pyogenic polyhedrons to various physical and chemical stimuli. It was discovered that mercuric chloride disinfection had no disinfection effect on polyhedrosis viruses, so it was discarded in sericulture disinfection. He also discovered that lime slurry has a powerful killing effect on polyhedral viruses, and is easy to obtain and cheap. He advocated the use of lime slurry to disinfect silkworm houses and silkworm tools, and created the lime slurry disinfection method, which played a great role in controlling viral diseases of silkworms. Then he successfully developed new methods for disinfection of silkworm bodies using Saili Powder to prevent stiffness, and disinfection of silkworm chambers and silkworm gear using Saili Powder Lime Slurry and Formalin Lime. These became the basic methods for disinfection of silkworm seed production and rural silkworm cocoon production at that time, and were popularized. Silkworm areas across the country gradually switched to other agents for disinfection until the production of Sailisan was stopped. His experiment on the method of sterilizing the surface of scattered eggs with bleaching powder solution was successful. He overcame the problems of sterilized eggs clumping and affecting hatching after the formalin solution was used to sterilize loose eggs. The loose eggs sterilized with bleaching powder solution were thoroughly disinfected and the eggs Because of its smooth grains and high hatchability, it has been widely used by silkworm breeding farms across the country. To this day, it is still the only method for sterilizing loose silkworm eggs. Because Cao Yisun's silkworm disease research results have made remarkable achievements in improving the practice of silkworm cocoon production, he was named an advanced worker in Zhenjiang City in 1956.
The main reason for reduced production or harvest failure in rural sericulture is caused by silkworm diseases, especially pus diseases. In the late 1950s, in order to explore the theory that pus disease could be induced by high and low temperature shock and poor leaf quality, which was widely circulated in Japanese silkworm disease circles at that time, research on the environmental induction mechanism of pus disease was carried out. After many experiments, new insights into the environmental induction of silkworm abscess were finally proposed. Experiments have shown that the essence of environmentally induced pustitis is that the silkworm body is stimulated by adverse conditions, causing normal physiological functions to be disrupted, resulting in a greatly reduced disease resistance of the silkworm body, and the silkworm body is infected by a very small amount of viruses present in the environment and pustitis occurs. This leads to the conclusion that thorough disinfection can prevent the occurrence of silkworm infectious diseases. Based on the new theory of micro-virus infection, a combined prevention and control technical protocol centered on eliminating pathogens and cutting off pathogenic infection pathways has been formulated to guide rural sericulture production and pay close attention to disease prevention and disinfection, which can effectively prevent the occurrence of infectious silkworm diseases. , which has brought the harm of silkworm disease under control in our country. The number of cocoons produced per box of silkworm seeds nationwide has now more than doubled compared to the early days of the founding of the People's Republic of China.