Ragweed (Ambrosia sp.) seeds in bird feed

Five years of monitoring and control for ragweed seeds in bird feed done by members of the IAG working group (International Association for Feedingstuff Analysis, Section Feedingstuff Microscopy)1. IntroductionCommon ragweed (Ambrosia artemisiifolia L.) is an invading plant with highly allergenic pollen and important seed production. Originating from North America, its spread throughout different European countries has been thought to be linked in the past to the import of cereals (Kiss, 2007), and more recently with contaminated bird feed and the germination of seedlings at the foot of the trough. Other ways of propagation are movements of soil and vehicles together with contaminated seed lots. In 2005, Delabays et al. (2005) and Taramarcaz et al. (2005) described the situation in Switzerland and Brandes et al. (2006) similarly observed the distribution and dispersal of ragweed in Germany. The latter authors suggested: “At the present climatic conditions a continued occurrence of A. artemisiifolia in Central Europe is highly possible, even more so under global change conditions of elevated temperature and/or carbon dioxide”. As a consequence, and although ecological or economical damage (on the crop yield) was considered low, control measures were suggested because of the allergenic properties of ragweed pollen. Several measures to be applied on growing plants of known populations were elaborated, together with preventive measures concerning the dispersion of seeds (seed sto