© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Invasive weeds: the case study of ragweed control in France France Ambroisia artemisifolia in Sunflower / Photo ACTA Reynoutria japonica / Photo ACTA Phytolacca americana/ Photo ACTA Stop to invasive weeds / Photo ACTA MODULE C18

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Introduction : Background Ragweed is an invasive weed Yield losses in summer crops like sunflower Capacities to develop into non-agricultural environments Very allergenic Photos ACTA

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Seed Young plants Beware of confusions ! Adults Identification Ambrosia artemisifolia Artemisia vulgaris Anthemis arvensis Drawings and Photos ACTA and INRA

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Biological cycle Ragweed in Rhône-Alpes (France) Drawings INRA Male inflorescence Seed = Achene Female flowers Plantlet Stage of development Flowering plant Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Germination Vegetative development Pollen transfer Fructification Seed production

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Dissemination Very low dispersal abilities Spread by agricultural tools Spread by contaminated soils Photo ACTA Drawings and Photos ACTA and INRA

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Development Spring and summer crops Intercropping period: Cereal, peas and rapeseed stubbles Fallows poorly maintained Abandoned agricultural land Roadsides, construction sites Photos ACTA & CETIOM Photos ACTA and CETIOM

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Hoeing In inter-row Control in spring crops Pre-emergence herbicide Only false-seed bed No chemical treatment : no selectivity Pre-emergence herbicide EmergenceSowing Post-emergence herbicide Only on tolerant cultivars Weeder Not easy in gravels soils Photos ACTA and CETIOM

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Control at harvest and in intercropping period AT HARVEST Harvest the contaminated fields after all the others Clean the harvester machines DURING INTERCROPS One intervention before flowering –To avoid pollen emission One intervention before graining –To avoid the reconstitution of the seed bank Cultivation : Stubble ploughing Non-selective herbicides at low rate Photos ACTA

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Control in non-agricultural environment Priority to prevention control –No seeds introduction with contaminated soils –Vegetalization of road, railway sides,… –Mulches in greenspaces Possibilities of curative control –If ragweed is non dominant :  Practice a high shearing (15 cm)  Use selective herbicides  Favour natural vegetalization –If ragweed is dominant :  Try to eliminate plants with non-selective herbicides or a low mowing  Repeat until raqweed become non dominant and then favorize vegetalization Photos ARVALIS & ACTA

© ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Conclusion Use of IPM General principles –Preventive measures  Beware to not import seeds from contaminated areas or with contaminated implements  Rapid vegetalization in non agricultural areas –Preferring non-chemical methods  Mechanical control is possible in agricultural and non- agricultural areas –Correct choice of pesticide and limitation of rate  Beware of pesticides transfer  You can reduce the herbicides rate on young plants Buffer zone / Photos ACTA