Has the Striga problem been solved? A field perspective critique of recent progress

Three root-parasitic witchweed (Striga) species can cause up to total loss of grain and legume crops for millions of farmers in Africa. The damage is initiated before Striga emerges from the soil. Four decades of resistance breeding, especially maize, have at best conferred localized moderate resistance that has not greatly increased yields. Recent innovative basic research has led to major advances that are herein evaluated in biocontrol, formulating suicidal germination stimulants and gene-edited crops. A mycoherbicide was able to become a commercial success because the innovators rendered the fungus hypervirulent, inexpensively cultivated it, formulated it as a seedcoat with ample nutrition for extensive growth, and determined target species specificity for regulators. A slow-release formulation of suicidal germination stimulants led to a Striga-free crop, but crop planting had to be impractically delayed by almost 3 months for the technology to work. Elegant basic research led to gene-edited crop plants secreting vastly reduced levels of Striga germination stimulant, leading to Striga asiatica-free fields under low seeding levels of the parasite. It is doubted that the results will carry over to fields infested with the far more virulent Striga hermonthica having seedbanks so large that the residual amount of stimulant emitted may result in heavy infestation. The editing approach should be extended to suppressing the genes responsible for Striga attachment and establishment, and the genes stacked for more robust resistance. Solving only the Striga problem is insufficient because farmers with Striga are also confronted with insect, pathogen and climate constraints that need simultaneous solutions. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.