Survey on weeds in arable crops in France
A survey was initiated in France to confirm earlier field reports stating a significant increase of several weeds. It focussed on the following 5 species of which 2 are on the EPPO list of invasive alien plants: Ambrosia artemisiifolia (Asteraceae, EPPO list of invasive alien plants), Sicyos angulatus (Cucurbitaceae, EPPO list of invasive alien plants), Abutilon theophrasti (Malvaceae), Vulpia myuros (Poaceae) and Orobanche ramosa (Orobanchaceae), and farmers from all parts of France were asked to provide information.
Ambrosia artemisiifolia: The management of this Asteraceae originating from North-America is difficult. This is particularly true in sunflower (Helianthus annuus) because this crop is also an Asteraceae. As several phytosanitary products are no longer authorised for environmental reasons, herbicide treatments of spring crops are more complex and expensive. The spread of this plant is also monitored in Italy, Switzerland and Hungary. In France, it has caused severe problems in the Rhône-Alpes region and is now spreading towards the North and South through human activities and exchanges of seeds for birds.
Sicyos angulatus: This North-American climber can strongly affect maize crops and is considered as a weed in Italy, Croatia and Japan. It has been predominantly observed in Haute-Garonne, Lot, Gironde, Aveyron, Ardèche and Hautes-Alpes. Surprisingly, results showed that the species was not merely restricted to the South-Western part of France, but was present almost all over the country. Nevertheless, this survey has limitations, as farmers may have confused S. angulatus with Bryonia cretica, an indigenous and very widespread species.
Chauvel B, Dessaint F, Lonchamp JP, Gasquez J (2005) Cinq élues et des candidates. Enquête sur les mauvaises herbes envahissantes en grandes cultures en France. Phytoma - La Défense des Végétaux 578, 16-20.