Tobacco broomrape (Phelipanche ramosa, Phelipanche aegyptiaca and Orobanche Cernua) is a widespread parasitic plant from the Orobanchaceae family, that causes important damage in tobacco crops. Broomrape is mainly present in Europe, Middle East and Asia and no satisfactory chemical control strategy is available for growers. A project combining breeding and agronomical efforts was initiated in France in 2016 involving research and technical partners to evaluate and implement an integrated broomrape control strategy. The objectives of this multidisciplinary approach were to improve the understanding of the genetic broomrape tolerances in connection to different crop strategies. After several years of herbicide treatment evaluation bringing no satisfactory results for growers, the key objective of this project was to develop a new approach based on the use of broomrape pathogens as biocontrol agents.

The breeding part of the project, led by Bergerac Seed & Breeding (BSB), focused on evaluating identified sources of tolerance to different broomrape populations and species. Testing Wika and two new tolerance sources on populations of broomrape collected in different countries revealed that the Wika recessive gene brings interesting tolerances to P. ramosa and P. aegyptiaca populations while none to O. cernua ones.

The biocontrol part of the project, led by Agroécologie and Arvalis, focused on hundreds of fungi isolated from symptomatic broomrape in 2017 and 2018. Based on morphotypes, a coarse visual identification and original plot locations, one hundred of them were evaluated for their pathogenicity to broomrape. This screening revealed a dozen fungi strains as promising mycoherbicide candidates but whose in situ efficacy on tobacco broomrape has yet to be validated.

Combining breeding efforts and new biocontrol strategies brings some hope to tobacco growers for an integrated control solution to broomrape parasitic activity.