AGRICULTURAL AND FOOD A gricultural A N D F O O D S ci ence Vol. 20, No. 1, 2011 Contents Hyvönen, T. 1 Preface Agricultural anD food science Hakala, K., Hannukkala, A., Huusela-Veistola, E., Jalli, M. and Peltonen-Sainio, P. 3 Pests and diseases in a changing climate: a major challenge for Finnish crop production Heikkilä, J. 15 A review of risk prioritisation schemes of pathogens, pests and weeds: principles and practices Lemmetty, A., Laamanen J., Soukainen, M. and Tegel, J. 29 SC Emerging virus and viroid pathogen species identified for the first time in horticultural plants in Finland in IENCE 1997–2010 V o l . 2 0 , N o . 1 , 2 0 1 1 Hannukkala, A.O. 42 Examples of alien pathogens in Finnish potato production – their introduction, establishment and conse- quences Special Issue Jalli, M., Laitinen, P. and Latvala, S. 62 The emergence of cereal fungal diseases and the incidence of leaf spot diseases in Finland Alien pest species in agriculture and Lilja, A., Rytkönen, A., Hantula, J., Müller, M., Parikka, P. and Kurkela, T. 74 horticulture in Finland Introduced pathogens found on ornamentals, strawberry and trees in Finland over the past 20 years Hyvönen, T. and Jalli, H. 86 Alien species in the Finnish weed flora Vänninen, I., Worner, S., Huusela-Veistola, E., Tuovinen, T., Nissinen, A. and Saikkonen, K. 96 Recorded and potential alien invertebrate pests in Finnish agriculture and horticulture Saxe, A. 115 Letter to Editor. Third sector organizations in rural development: – A Comment. Valentinov, V. 117 Letter to Editor. Third sector organizations in rural development: – Reply. V o l . 1 20, (2011) 1–118 ISSN electronic edition 1795-1895 The Scientific Agricultural Society of Finland MTT Agrifood Research Finland www.mtt.fi/afs AgriculturAl AND FOOD ScieNce Agricultural and Food Science publishes original reports on agriculture and food research. The papers, which are of international interest but feature a northern perspective, cover a wide range of topics in basic and applied research. Submissions are internationally refereed. Review articles and research notes will also be considered. Readers are welcome to send their comments to the journal (Letter to the Editor). Publishers The Scientific Agricultural Society of Finland MTT Agrifood Research Finland editorial board Juha Helenius - Editor Tapani Alatossava Xavier Irz Eila Turtola Pekka Uimari Kaisa Kuoppala - Associate editor Address Agricultural and Food Science Editorial Office MTT Agrifood Research Finland FI-31600 Jokioinen, Finland http://www.mtt.fi/afs From volume 19 the publication of Agricultural and Food Science is available as an Open Access journal, free of charge to the user. The issues and articles published since volume 11 have also been transferred to the Open Access mode. Publishing continues in electronic format only, available on the journal's web-pages (www.mtt.fi/afs), or via database links or where the journal is indexed. The printing of special issues will still be considered should the applicant offer to provide the resources. Single printed issues up to volume 18 may be obtained from Bookstore Tiedekirja, Kirkkokatu 14, FI-00170 Helsinki, Finland, e-mail: [email protected]. The price of a single issue is 17 + VAT within the EU. The journal is indexed by the following databases: AGRIS, BIOSIS, CAB Abstracts,Cambridge Scientific Abstracts, Current Awareness in Biological Sciences, Current Contents, FSTA, Pascal, Scopus, Science Citation Index, ISI Web of Science and Ingenta. Copyright: Agricultural and Food Science AGRICULTURAL AND FOOD SCIENCE Foreword Principal Research Scientist Terho Hyvönen Co-Editor of the Special issue MTT Agrifood Research Finland, Plant Production Research, FI-31600 Jokioinen Alien pest species in agriculture and horticulture in Finland An alien species is defined as an organism that occurs outside its natural past or present range and dispersal potential, and whose dispersal and presence is due to intentional or unintentional human action. Recent development in human activities has affected both the immigration and success of alien species to a greater extent than ever previously. The growth of global trade and travel has increased immigration pressure in terms of the number of potential immigration pathways and events. Changes in land use have provided new niches and human-mediated climate change has created more suitable climatic conditions that favour the success of many alien species outside their natural ranges. In their new ranges, alien species usually harm the recipient ecosystems in several ways and control of new invaders may require considerable ef- fort once they have become established. Therefore, anticipating immigration is important for successful control of alien species. There is a long history of range expansion of alien species aided by humans in agriculture and horti- culture. Crop species and horticultural plants themselves are alien species in most regions of the world. Furthermore, their production has provided niches for numerous plant pathogens and insect pests and cre- ated open habitats for weed species. Modern year-round greenhouse production has enabled the success of tropical and sub-tropical pests also in the northern climate zones. Greenhouses can also act as stepping- stones for exotic pests to transfer to the natural surroundings. In agricultural and horticultural production, alien pest species cause economic loss by decreasing the production or lowering the quality of products. Regular control measures are applied to limit their populations, which naturally increases costs. In the future, climate change can be assumed to bring challenges in the form of new alien pest species. This is especially true for the northern regions, such as Finland, where the climatic conditions have to date suc- cessfully prevented the establishment of permanent populations of many alien pest species. Introduction of new crop species – also a consequence of climate change in northern regions – will likely favour some new alien pests. 1 AGRICULTURAL AND FOOD SCIENCE . This special issue of Agricultural and Food Science focuses on the alien pest species associated with agricultural and horticultural production in Finland. The main aim of the special issue is to provide up- dated reviews on the current status of major groups of alien pest species, including plant pathogens, insect pests and weeds. Anticipation of the future immigration of alien pest species requires the development of pest risk-assessment methods as well as modelling tools for predicting the potential risk of expanded geographical distribution. This special issue addresses the study of the agricultural and horticultural pests in the context of invasion ecology, providing a theoretical framework for understanding species invasions on large spatial scales. In the increasingly globalized world, solutions for local pest problems may lie in better understanding of the relevant phenomena in a wider context. 2 AGRICULTURAL AND FOOD SCIENCE Vol. 20(2011): 3–14. Pests and diseases in a changing climate: a major challenge for Finnish crop production Kaija Hakala, Asko O. Hannukkala, Erja Huusela-Veistola, Marja Jalli and Pirjo Peltonen-Sainio MTT Agrifood Research Finland, Plant Production Research, FI-31600 Jokioinen, Finland, email: [email protected] A longer growing season and higher accumulated effective temperature sum (ETS) will improve crop pro- duction potential in Finland. The production potential of new or at present underutilised crops (e.g. maize (Zea mays L.), oilseed rape (Brassica napus L.), lucerne (Medicago sativa L.)) will improve and it will be possible to grow more productive varieties of the currently grown crops (spring wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), oats (Avena sativa L.)). Also cultivation of autumn sown crops could increase if winters become milder and shorter, promoting overwintering success. Climatic conditions may on the other hand become restrictive in many ways. For example, early season droughts could intensify because of higher temperatures and consequent higher evaporation rates. Current low winter temperatures and short growing season help restrict the development and spread of pests and pathogens, but this could change in the future. Longer growing seasons, warmer autumns and milder winters may initiate new problems with higher occurrences of weeds, pests and pathogens, including new types of viruses and virus vectors. Anoxia of overwintering crops caused by ice encasement, and physical damage caused by freezing and melting of water over the fields may also increase. In this study we identify the most likely changes in crop species and varieties in Finland and the pest and pathogen species that are most likely to create production problems as a result of climate change during this century. Key-words: climate change, crop, overwintering, pathogen, pest, virus, vector, winter © Agricultural and Food Science Manuscript received January 2010 3 AGRICULTURAL AND FOOD SCIENCE AGRICULTURAL AND FOOD SCIENCE Hakala, K. et al. Pests and diseases in a changing climate Vol. 20(2011): 3–14. Introduction the most recent decades and especially in the 2000s the increase has accelerated, the period 1995–2006 being the warmest ever recorded (IPCC 2007a). Finland lies between latitudes 60º and 70ºN, but In Fennoscandia, the growing season has become despite its northern location supports active agri- one to three weeks longer during 1890–1997, with culture on about 2.3 million hectares of arable land