noun
powdery mildew
A plant disease caused by fungi, appearing as a white powdery coating on leaves and stems. Common in gardening and agriculture.
キュウリの葉にうどんこ病が発生した。
Powdery mildew appeared on the cucumber leaves.
うどんこ病の予防には風通し
Good ventilation is important for preventing powdery mildew.
From うどん粉 (udon flour) + 病 (disease), referring to the white flour-like appearance of the fungal growth.