Are root parasitic broomrapes still a good target for bioherbicide control?

Root parasitic weeds of the genera Orobanche and Phelipanche (commonly named broomrapes) are responsible for enormous yield losses of several crops all around the world. Traditional weed management methods, including among others the use of herbicides, soil fumigation and solarisation, and mechanical, agronomic, or physical methods, may have limits of use or can provide a modicum of control. Difficulties in controlling parasitic weeds are due both to the enormous number of seeds produced by each plant that can remain viable, even in the absence of a host, for many years and to the unique physiological and biological properties of the parasite. Although considered a suitable and promising approach for a long time, biological control, in particular with the use of microbial organisms or with compounds stimulating or inhibiting seed germination, has had no commercial success, and no products have reached the market. The present article aims at making a quick overview of the bioherbicide approaches attempted until now, briefly discussing the causes of the failures and the possibility to improve biocontrol agents' effectiveness. Indeed, despite the failures, the 'bioherbicide' approach deserves a renewed interest in light of the enormous scientific and technological progress made in the last years, which offers new chances of success.