Assertion: mulberry's leaf | /r/ObjectUse | used in china
Facets:
value: as the primary diet for silkworms
type: MANNER
value: since at least 2600 b.c.
type: TEMPORAL
Source sentences:
text: The leaves of this tree have been used in China since at least 2600 B.C. as the primary diet for silkworms used to make silk.