The "bosco" is a set of intertwined branches of rapeseed (a once very widespread plant from which it was also possible to extract oil, a commodity that was not at all common) or bundles of broom, heather, birch, dry bean plants, on which the silkworms climbed, finding support to spin their cocoons. The "bosco" was placed in the silkworm farm about 30 days after the silkworms were born, when they had reached their full larval development and were ready to build the cocoon to complete the metamorphosis from larva to chrysalis and then to butterfly.