Striga, commonly known as witchweed or witches weed, is a genus of parasitic plants that occur naturally in parts of Africa, Asia, and Australia. It is in the family Orobanchaceae. Some species are serious pathogens of crop cereals, with the greatest effects being in savanna agriculture in Africa. It also causes considerable crop losses in other regions, including other tropical and subtropical crops in its native range and in the Americas. Witchweeds are characterized by bright-green stems and leaves and small, brightly colored and attractive flowers. They are obligate hemiparasites of roots and require a living host for germination and initial development, though they can then survive on their own.