When was powdery mildew introduced to Europe?

• A. 16th century
• B. 20th century
• C. Mid-1800s
• D. 17th century

Answer: (C)

Powdery mildew’s introduction to Europe highlights how plant diseases can spread with global trade and movement of plant material. In grapes, the fungus that causes powdery mildew is not native to Europe and was first documented there in the mid-1800s, with records pointing to around the 1840s–1850s. That timeframe reflects when the disease began appearing in European vineyards and becoming a widespread problem.

The other timeframes don’t align with historical records: earlier centuries would predate the scale of international plant exchange that brought the pathogen to Europe, while the 20th century would place the arrival too late given how quickly powdery mildew became established after its introduction. Therefore, the mid-1800s is the best match for when powdery mildew was introduced to Europe.