Effect of Silkworm Larval Population Density on Quality Cocoon Production

Larval population has a great impact on biology and physiology of insects including silkworm Bombyx mori L. The present study was conducted on hybrid CSR₂ × CSR₄, comprising of seven treatments. Thepopulation density of silkworm larvae varied from 250 worms per plastic tray size (6ft.) to 550 wormsper tray to evaluate and recommend the optimum silkworm population number required to be reared under specific unit area commercially. Fourteen commercial characters were studied and evaluated by cumulative Mano’s Evaluation Index (E.I.) method. The late age larval duration of the silkworm is directly proportional to the larval density, while as larval weight depicts relatively inverse relation. The highest E.I value of 56.30 was obtained for 250 population size. For population size of 300, 350, 400 silkworm the E.I values recorded were, 54.16, 52.42, 51.21 , respectively. The study also revealed that with the increase in larval population per square feet, the economic rearing parameters get reduced in metric traits. More density affects quantitative traits than qualitative traits. The larval population density 300 to 400 larvae/tray is economically and commercially optimum and advocated for field rearing.