Opinion of the Scientific Panel on Plant Health on the pest risk assessment made by Lithuania on Ambrosia spp

Following a request from the European Commission, the Panel on Plant Heath was asked to issue a scientific opinion on the pest risk assessment made by Lithuania on Ambrosia spp., requested by Lithuania to be inserted as a harmful organism in point c of section II, part A of Annex I to the Council Directive 2000/29/EC.The Lithuanian risk assessment relates to three species of the genus Ambrosia: A. artemisiifolia L. (common ragweed), A. trifida L. (giant ragweed) and A. psilostachya DC (perennial ragweed). These plants are native to North America and are considered invasive both in their native area and in other parts of the world, including several countries in Europe. Ambrosia spp. are of particular public concern due to the allergenic properties of their pollen.The Panel examined in detail the three documents provided by Lithuania. The review evaluated the accuracy and relevance of data, the information provided for pest risk assessment purposes, the quality and quantity of data considered, and the quality of methods applied to conduct the risk assessment. The review was based on the principles and terminology of the International Standard on Phytosanitary Measures ISPM No. 11: Pest risk analysis for quarantine pests including analysis of environmental risks and living modified organisms (2004) by the International Plant Protection Convention (FAO IPPC, 2006).With regard to the criteria of a quarantine pest, the Panel on Plant Health concludes that the Lithuanian documents do not provide sufficient evidence to assess on a scientifically sound basis whether Ambrosia spp. qualify as quarantine pests for Lithuania.The most important shortcomings are:* The pest of phytosanitary concern for Lithuania has been identified at a genus level. The genus Ambrosia includes too many species to be considered together, even if only three species A. artemisiifolia, A. trifida and A. psilostachya are deemed to pose a threat. Biological and ecological data clearly indicate that each of the three species would require its own or a better structured pest risk assessment clearly discriminating among the species of concern.* The documents clearly state that A. artemisiifolia and A. trifida are present in Lithuania. A. psilostachya is not reported. A table showing the number of plants of A. artemisiifolia in several sites and years is provided. Two maps showing sites infested with A. artemisiifolia and A. trifida in Lithuania are provided but without any date. Detailed information on the abundance of A. artemisiifolia and A. trifida over the years is necessary. Moreover, more specific details are needed on their habitats and their status (established or not).* Data on the different introduction pathways need to be revised. The current distribution for each of the three species outside Lithuania, especially in countries that are important trading partners of Lithuania, should be added to identify in more detail the risk for further introduction. More accurate data are required on the assessed pathways of the three species; alternative pathways (via bird seed, spreading by soil, machinery and tyres) should also be considered.* The impacts on crop yields and on human health are discussed in two documents provided by Lithuania, but it is not possible to conclude from these documents that Ambrosia spp. would be of potential economic importance for Lithuania, i.e. through direct or indirect effects on cultivated plants in agriculture, uncultivated/unmanaged plants, wild flora, habitats or ecosystem. Impacts on human health are also not given sufficient attention.* The endangered area is not defined.However, there is scientific evidence both in the provided document and the existing literature that Ambrosia spp. can cause detrimental impacts on human health due to their allergenic properties. The control of Ambrosia spp. is difficult in certain crops and in non cultivated areas.The Panel on Plant Health therefore recommends that the pest risk assessment should be revised and updated. As stated above, it should be undertaken for each of the species of concern. In order to assess the risks related to each Ambrosia spp., additional information and amendments would be needed regarding the following aspects:* current distribution and abundance in Lithuania of the species already present A. artemisiifolia and A. trifida (providing references and/or official surveys data), including listing of habitats and the status (established or not);* current distribution of Ambrosia spp. outside Lithuania, to identify in more detail the risk of further introduction into the country;* more accurate data on the pathways already assessed; consideration of alternative pathways (bird seed, spreading by soil, machinery and tyres);* more accurate assessment of the potential for establishment in Lithuania (including photoperiod and climatic conditions, and other abiotic factors);* update on the efficacy of control measures;* effects on crop yield for the main crops. This is important as the levels of infestation with Ambrosia spp. and the efficiency of the methods of control are not the same for all crops;* more accurate assessment of potential economic importance (including impacts on human health and other social impacts);* identification of the endangered area;* discussion of uncertainties on all aspects of the pest risk assessment.