Assertion: sunflower's leaf | /r/AtLocation | petiole
Facets:
value: under severe infestations
type: OTHER
Source sentences:
text: Rust, incited by the fungus Puccinia helianth, is characterized by cinnamon-colored spots which occur primarily on the leaves, which under severe infestations, also occur on the stems, petioles, bracts, and the back of the head.