The overall aim of the project is to contribute to the reduction of the prevalence of Ambrosia artemisiifolia in European countries in order to reduce the burden on public health, agriculture and biodiversity. This will consist of developing strategy elements for the reduction of the occurrence of ragweed and its pollen in countries where the species is already established, e.g., Hungary, Slovenia, parts of Austria, and South-eastern Central Europe and for the prevention of further import and spread in countries not yet heavily infested, such as Germany, the Netherlands and Northern European countries. To this end the gaps in the existing information needed for understanding historical successes and failures of prevention, control and eradication activities will be analysed. This includes
- a fuller understanding of critical elements in the life history of common ragweed,
- an evaluation of chemical, mechanical and biological control measures.
Assessing the power of various control methods must consider not only their effectiveness as regards their potential to completely destroy populations of the plant and their seed bank, but also their efficiency with regard to cost and their effects on non-target organisms. Improvement of mechanical control methods has a special importance in the course of policies that strive to minimise the use of pesticides.
The usability of different control measures depends on population characteristics (size and age of populations) and the special features of sites occupied by common ragweed. In regions with low infestation rates measures aiming at eradication can be applied whereas in heavily infested regions control measures can only result in the suppression of populations.
Due to the strong negative impact of common ragweed there is a long history of control and eradication trials. A successful eradication was achieved as early as the 1930s in Canada (Comtois 1991). A large body of literature about the species’ ecology and life history, its impacts, distribution and its reaction to control measures has accumulated over time. To date, however, no comprehensive overview of the existing information exists, most of the knowledge is scattered over different scientific disciplines, e.g., aerobiology, ecology, herbology; regions, and languages.
During the last years, efforts have increased to understand the ecology and distribution dynamics in Europe as well as to improve preventive and control measures. Several national control programmes and legislations have been set up, e.g., in Hungary (Szigetvari & Benkö 2009), France (see www.ambroisie.info), Switzerland (Bohren 2006) or Germany (Starfinger 2008, 2009).
International activities include the work of the European and Mediterranean Plant Protection Organisation (EPPO 2007, 2008), several conferences dedicated to the species (e.g., the “First International ragweed Conference” Budapest, September 2008, an international workshop on “Invasive Alien Species in EU countries” held in Budapest October, 2009, a workshop hosted by CABI in December, 2009, etc.). An “International Ragweed Society” that aims at improving the knowledge base and at awareness raising about the negative impacts was founded in 2009 (http://www.internationalragweedsociety.org).
With the specific aim to assess the importance of further introduction of Ambrosia to countries where it is not yet widely distributed, the European Commission has asked EFSA to provide a scientific opinion on the effect on public or animal health or on the environment of the further distribution of Ambrosia spp. in the European Union, and on the importance of the pathway of bird feed in particular. This opinion was published by EFSA in June, 2010. It contains a review of the literature on distribution and impacts (EFSA 2010).
In order to improve the understanding of control methods, an international research project funded by the EC under the ERANET project “EUPHRESCO” was conducted in 2008/2009. The project was carried out by partners in CH, DE, DK, and SI. The project resulted in a scientific report (Holst 2009) and recommendations on the use of control techniques in six languages:
(http://xwww.agrsci.dk/ambrosia/home/introduction.html). As a short project with limited funds, this project’s team could conduct some experiments in a number of countries but was not able to fully evaluate all the outcome or to follow up over a longer period of time. The proposed project will build on and expand results of the former, in particular with regard to mechanical measures and herbicide treatments.
- Conduct experiments on dormancy and germinability
- Assess risks of introducing ragweed populations with transporting commodities
- Provide data on missing biological characters to improve control and eradication of Ambrosia
- Improve and adapt physical methods to control Ambrosia
- Define key parameters and optimal conditions for a high efficacy of physical control methods
- Describe strategies for sufficient and cost-effective integrated control strategies in relevant uses
- Determine of optimal timing and dosage of herbicide application
- Provide sustainable herbicide solutions for critical and sensitive uses like minor crops, non-cropping areas and protected areas
- Work out of the specific impact of the legal, climatic and agronomic conditions in the participating countries
- Define the key parameters for a high herbicide efficacy against Ambrosia
- Define levels of interaction between Ambrosia and surrounding vegetation
- Analyse the impact of Ambrosia on plant species richness and composition of the vegetation
- Review the effects of different control measures against Ambrosia on biodiversity
- Inform national authorities, stakeholders and the public about project results.
- Disseminate guidance for successful and cost efficient control and eradication of Ambrosia
- Identify relevant needs for action
- Ensure continuation of research work and implementation