Biology and life cycle

Broomrape (Orobanche ramosa) parasitises exclusively the roots of dicotyledonous plants such as tobacco, but it is not specific to these species. This plant produces neither roots nor chlorophyll, and it is totally dependent on its host for nutrition.
 
The end of seed dormancy is related to the production of root exudates of the host plant. The parasite is difficult to detect in its early lifecycle, and first occurs in summer by the appearance of the tip which consists of several flowering spikes from fifteen to forty centimeters in height. These flower spikes have pale-blue to purplish-blue flowers.
 
The rate of multiplication of the parasite is very important (600 to 800 seeds per flower) and the seeds are very small (350 to 450 µm long).
 
Occurrence

Broomrape has been reported in many tobacco-producing departments in France (although the degree of infestation varies from one region to another. Currently, almost all tobacco-growing cooperatives are affected by this scourge (distribution map is available on the following link: Tela Botanica). 

How to limit its spread?

From the various studies conducted by ANITTA (French National Technical Center for Tobacco Professionals) in collaboration with the tobacco-growing cooperatives and the University Pierre et Marie Curie, a number of parameters were identified to limit the spread of Orobanche. These measures are either preventive, in case of outbreaks detected in nearby fields, or curative in case of confirmed presence of the parasite in the field.
This parasite is not thoroughly known, but research continues and will generate other essential information to control it.