Influence of the timing of mulberry leaf powder obtaining in the composition of artificial diet on the development and productivity of the silkworm Bombyx mori L.

The aim of this study was to detect the effect of mulberry leaf powder, obtained during the summer and autumn seasons, and included in the silkworm artificial diet on the silkworm development and productivity. The experimental work was carried out at the Scientific Center on Sericulture - Vratsa at the Agricultural Academy during the period 2022-2025. Three options for larval growing with artificial diet, respectively, containing mulberry leaf powder produced in the months of October, September and July (control) were tested. It was found that growing the larvae with artificial diet containing mulberry leaf powder, harvested in the month of October, leads to a decrease in vitality from hatching to the beginning of the 4th instar and to a significant extension of the larval period, and a decrease in the weight of the cocoon and silk shell. Growing the larvae on artificial diet containing mulberry leaf powder, harvested in the month of September, had no significant effect on their vitality and duration of the larval period, but led to a slight decrease in the weight of the cocoon and silk shell. It is recommended that the composition of the artificial diet should not include mulberry leaf powder harvested in the months of September and October alone, but in combination with mulberry leaf powder harvested in the month of July.