Witchweed is a group of tropical plants, some of which are destructive to crops. There are dozens of species (kinds) of witchweed. They are native to the tropics of Africa and Asia but have been introduced to other countries. Certain species are parasites of corn, sorghum, sugar cane, and other commercially important plants.
Witchweeds are branched plants about 6 to 30 inches (15 to 75 centimeters) tall. They have two-lipped flowers. Their tiny seeds germinate when they come in contact with the host’s root. The young witchweed plant grows underground for up to six weeks, after which it emerges into the light and makes some of its own food by photosynthesis. It continues to take water and mineral salts from the host plant. Witchweed causes the host plants to turn yellow and have stunted growth.
