A revision of emergent pests in major agricultural and horticultural crops in Finland

Climate change and changes in agricultural production will benefit pest species in Northern Europe by decreasing climatic restrictions and increasing availability of host plant species. We reviewed changes in the status of agricultural and horticultural pests that were identified in 2011 as potential future threats to Finnish plant production and identified species that were not mentioned in the previous review but are considered emergent pests now. In field crops, the emergent weed species were Echinochloa crus-galli and Solanum nitidibaccatum, the emergent plant pathogens Zymoseptoria tritici, Fusarium graminearum and F. langsethiae and rusts (Puccinia spp.) in cereals, as well as Potato mop-top virus (PMTV) and emerging species of potato blackleg bacteria (Dickeya and Pectobacterium spp.). The migrant Lepidopteran, Autographa gamma, the established alien sawfly Athalia rosae in oilseed crops, the alien Bruchus rufimanus in faba beans, native Chaetocnema spp. in spring cereals and wireworms (Elateridae) in potato were the emergent arthropod pests of field crops. In horticultural crops, Aculops lycopersici, Bemisia tabaci, Rhagoletis batava, Igutettix oculatus, Hoplocampa flava and Hoplocampa minuta and Otiorhynchus spp. were emergent alien arthropod pests, while the greenhouse whitefly, various aphids, thrips, and Phytonemus pallidus and Tetranychus urticae were emerging mainly due to withdrawal of chemicals. Warm early summers, banning of chemicals and importation of plants and seeds were considered the major drivers of the change. Several pests not considered potential future threats in 2011 are now emergent pests in Finland, underlining rapid changes in pest emergence and the challenges of their prediction. Utilization of citizen science platforms is encouraged to enhance early observation of emerging pests.