The Finnish Forest Research Institute and Agrifood Research Finland recommend the use of healthy domestic planting material as part of the Integrated Plant Protection Program
New research (Figure 1) shows that the number of introduced pests increases exponentially in Europe. They have caused widespread damages around the world. For example, the East Asian Ash decline disease has destroyed large areas of ash forests. The future of commercial use of European beech forests is becoming uncertain due to infections by introduced fungus-like organisms, several various Phytophthoras. Also in agriculture, the increased use of imported plants has led to problems because of the accompanying pests and diseases. Most recently, Finnish strawberry was compromised due to strawberry red core -disease that has spread to dozens of farms with imported plants.
Damages by introduced pests can cause significant costs. For example according to the Finnish Food Safety Authority Evira the discovery of the pine wood nematode in the Finnish nature would require eradication operations that would cost 5-19 million per each detected case of a few infected trees. Unsuccessful control can lead to much greater economic losses: for example the spreading of Dutch elm disease on the island of Gotland in Sweden is estimated to cost 10 to 240 million per year, depending on how it is calculated. The costs would be considerably higher if similar injuries would affect the important tree species spruce, pine or birch in Finland. Ending of strawberry cultivation in Finland would force many farmers out of the industry and lead to huge economic losses in many municipalities. The recently discovered fire blight in Estonia would in turn give rise to substantial eradication actions in orchards and private gardens if discovered in Finland.
Risks caused by imported plants have been little known among agricultural and forestry producers, which has led to the steadily increasing importation of plants. Imports of seedlings of berry plants has increased throughout the time that Finland has been a member of the EU, and currently more than 75% of planted strawberry seedlings are imported. In recent years, also the import of planting material for raspberry and apple orchards has increased. Even vegetable seedlings are imported. The trade of ornamental plants has continued to grow and the number of countries of origin is increasing.
New research results (Figure 2) show that over the past three decades, trade of live plants acted as pathway for more than 70% of the forest pathogens that have spread to Europe and between European countries. Thus, the use of plant material grown abroad causes a substantial risk for the Finnish forest health and for the whole forest-based sector. However, not only imported tree seedlings cause a threat to forest health but also imported ornamentals planted in the built environment.
In all EU countries, the principle of integrated pest management (IPM) has to be followed from the year 2014 onward. An appropriate preventive pest management method is the use of healthy seedlings. Domestic production free of pests and pathogens is possible for seedlings of fruit and berry species and forest trees.
Based on the above described new research information and the IPM guidelines the Finnish Forest Research Institute and MTT Agrifood Research Finland recommend that from the beginning of 2014, especially in forest regeneration areas but also in other areas (gardens and the built environment) only seedlings from domestic production should be applied.
|Figure 1. Observations of introduced pathogens in Europe from 1800 to 2008.
||Figure 2. Substrate on which alien forest pathogens most probably arrived in Europe 1800-2008.
Figures: Santini, A., Ghelardini, L., De Pace, C., Desprez-Loustau M.L., Capretti, P., Chandelier, A., Cech, T., Chira, D., Diamandis, S., Gaitnieks, T., Hantula, J., Holdenrieder, O., Jankovsky, L, Jung, T., Jurc, D., Kirisits, T., Kunca, A., Lygis, V., Malecka, M., Marcais, B., Schmitz. S, Schumacher, J., Solheim, H., Solla, A., Szabò, I., Tsopelas, P., Vannini, A., Vettraino, A.M., Woodward, S., Webber, J., & Stenlid, J. 2013. Biogeographic patterns and determinants of invasion by alien forest pathogenic fungi in Europe. New Phyt. 197, 238-250.
- Professor Jarkko Hantula, Finnish Forest Research Institute, email: jarkko.hantula(a)metla.fi
- Senior researcher Michael Müller, Finnish Forest Research Institute, e-mail: michael.mueller(a)metla.fi
- Senior researcher Päivi Parikka, Agrifood Research Finland, e-mail: paivi.parikka(a)mtt.fi
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