Parthenium hysterophorus is a fairly substantial annual herb of the family Asteraceae, native to the southern US, Mexico and Central and South America. The plant was unintentionally introduced in several countries and has become a serious agricultural and pasture weed in parts of Australia, Asia, Africa and the Pacific islands. It grows in many soil types and in a variety of (disturbed) habitats. The species aggressively colonizes disturbed areas, can be harmful for livestock and crops, and can cause allergic reactions (respiratory problems, contact dermatitis) to humans. As far as known, the plant has not yet been observed in the Netherlands.