Phylloxera is best described as what?

• A. A grape louse that damages leaves only.
• B. A fungal disease.
• C. A grape louse that attacks the vine's rootstocks and nearly wiped out the vineyards of Europe in the 19th century.
• D. A beneficial insect.

Answer: (C)

Phylloxera is an insect pest that attacks grapevines, specifically the root system. It’s the root-damaging form that caused a massive crisis in European viticulture during the 19th century, as European Vitis vinifera vines had little to no resistance. The devastating root damage led to widespread vine decline and death, nearly wiping out vineyards until a solution was found: grafting European vines onto resistant American rootstocks. This is why the best description is a grape louse that attacks the vine’s rootstocks and triggered that historic European catastrophe. It’s not a fungal disease, not a beneficial insect, and it’s known for its root rather than leaf damage.