Ultraviolet Disinfection of Air in Incubatory and Silkworm Rearing Rooms

Abstract

Aims: This study aimed to evaluate the effectiveness of ultraviolet irradiation combined with air ionization for disinfecting incubatory and rearing rooms in sericulture, and to determine its impact on hatching rate, larval survival, disease incidence, larval biomass, and cocoon productivity of Bombyx mori L. Study Design: A multiyear controlled experiment with four treatment variants, including ultraviolet exposure at different durations and intensities, compared with a non-treated control group. Place and Duration of Study: The experiments were conducted at the Sericulture Research Institute, Tashkent, Uzbekistan, during the spring seasons of 2023–2025. Methodology: Larvae of the hybrid “Ipakchi-1 × Ipakchi-2” were incubated and reared in rooms equipped with bactericidal ultraviolet lamps (wavelength 254 nm, 90 W) and an electro-technological air ionization system. Treatments included ultraviolet exposure for 10 minutes and 30 minutes per day, as well as irradiation with two lamps. Each treatment consisted of five replications of 100 eggs. Hatching rate, larval survival, disease incidence, larval weight across instars, and cocoon productivity indicators were recorded. Cocoon, shell, and larval weights were measured using analytical scales, and biological indicators were assessed according to standard sericultural procedures. Results: Ultraviolet treatment increased the hatching rate to 99.0% compared with 95.0% in the control. Larval survival reached 86.5–90.1%, improving by 2.2–5.8% relative to the control (84.3%). Disease incidence decreased to 1.06–2.1%, compared with 3.1% in untreated groups. The mean weight of 50 fifth-instar larvae increased to 79.9 g compared with 70.4 g in the control, while individual larval weight rose to 1.59–1.60 g versus 1.42 g. Cocoon shell weight reached 0.365 g and silk content 22.8%, exceeding the control values of 0.304 g and 20.9%. Conclusion: Ultraviolet irradiation combined with air ionization is an effective, environmentally safe method for reducing microbial contamination in sericulture facilities. It enhances larval viability, reduces disease incidence, and improves cocoon yield and quality, making it a practical component of modern industrial sericulture.