1. a type of fungus that causes powdery mildew disease in plants
Usage: botanical; plant pathology

Examples

• The grape vines were infected with oidium, causing white powdery spots on the leaves.
• Farmers use fungicides to control oidium in their vineyards.
• Oidium can severely damage crops if left untreated.
• The botanist identified oidium as the cause of the plant disease.
• Wine producers monitor their grapes carefully for signs of oidium infection.