Lammert Bastiaans

Societal Impact Statement Parasitic weeds in African rice systems threaten household‐level food security and income generation. Most affected farmers are smallholders with limited capacities to address these pests. Obligate parasites Striga asiatica and Striga hermonthica (witchweed) are problematic in rainfed upland rice, affecting approximately 312,000 households. Facultative parasite Rhamphicarpa fistulosa (rice vampireweed) has more recently become problematic in rainfed lowland rice, affecting approximately 133,000 households. A better appreciation of differences in biology, ecology and host–parasite interactions between these weeds, and the implications for species‐specific management, will inform awareness and preparedness among regional actors.