Tobacco broomrapes (Phelipanche ramosa, Phelipanche aegyptiaca and Orobanche Cernua) are widespread parasitic plants from the Orobanchaceae family, that cause important damage in tobacco crops. Broomrapes are 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 treatments 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, still led by BSB, focused on evaluating identified sources of tolerance to different broomrape populations and species. Testing Wika and two new tolerance sources to populations of broomrapes 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 populations. New sources seem to bring a potential of tolerance breeding to O. cernua.

The biocontrol part of the project, led by Agrosup Dijon, France, focused on hundreds of fungi isolated from symptomatic broomrapes 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. One candidate has been selected to realise the first trials in field and promising results including a decrease of broomrape pressure was observed in 2021.

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