Evaluation of Agronomic Practices for Controlling Branched Broomrape via Seed Bank Quantification and Parasite Mapping in France

Branched broomrape (Phelipanche ramosa) is an obligate parasitic plant causing significant yield losses in oilseed rape, hemp, and tobacco in France. Infested plots were geographically mapped, revealing hotspots in Poitou-Charentes, Vendée, the North-East, and sporadically in the South, and molecular analyses identified three genetic types with regional dominance. Field and lab trials assessed rapeseed seed hulls as a germination stimulant and screened 76 weeds and 34 crops under artificial infestation. Several trap crops and non-hosts, including flax, corn, and sunflower, effectively reduced the parasite’s seed bank, though field variability and unexpected results warrant further research.