noun
Gymnosporangium rust; rust disease
A plant disease caused by Gymnosporangium fungi, often affecting fruit trees like pears and apples, characterized by reddish spots on leaves.
梨の葉に赤星病が発生した。
Gymnosporangium rust appeared on the pear leaves.
赤星病の予防には殺菌剤の散布
Spraying fungicide is effective for preventing rust disease.