Infestans

Infestans is a Latin present-participle adjective meaning “infesting” or “attacking,” and it is used in biological nomenclature as a species epithet to denote a pest or parasite that infests a host. The term appears most prominently in the name Phytophthora infestans, an oomycete pathogen famous for causing late blight in potatoes and tomatoes.

Phytophthora infestans belongs to the genus Phytophthora and is a major plant pathogen. It reproduces both sexually and asexually and spreads through sporangia that release motile zoospores in wet conditions. Infected plants exhibit leaf lesions, collapsing stems, and tuber rot, with outbreaks favored by cool, moist weather. The pathogen was responsible for the severe potato blight that contributed to the Great Irish Famine of the 1840s and remains a persistent threat to solanaceous crops worldwide. Management typically involves resistant cultivars, timely fungicide applications, crop rotation, sanitation to remove infested material, and vigilant disease monitoring. Advances in genomics and diagnostic tools have improved surveillance, breeding for resistance, and targeting of control strategies.

Beyond Phytophthora infestans, the epithet infestans is used in other taxonomic names to indicate infestation or parasitism, following Latin naming conventions. However, Phytophthora infestans is by far the most historically notable organism bearing the epithet, due to its agricultural and historical impact.