Striga hermonthica : a pretty plant and a nasty parasite

Striga hermonthica. Image credit: United States Department of Agriculture: Agricultural Research Service (on wikimedia commons).

Striga hermonthica. Image credit: United States Department of Agriculture: Agricultural Research Service (on wikimedia commons).

This month’s organism is Striga hermonthica, commonly known as purple witchweed. It is a good example of how looks can be deceiving. From above ground S. hermonthica looks fairly harmless with dainty purple flowers.

However, Striga hermonthica belongs to a genus (Striga) of parasitic plants occurring naturally in Africa, Asia and Australia. S. hermonthica hosts include the economically important crops sorghum and rice. Infection with Striga species can cause severe disease symptoms including stunting, wilting and bleaching of leaves. Striga infestations are an especially big problem in Africa, causing an estimated 1 billion USD worth of damage to crops each year (1). Continue reading