First records of the Z-Race of European Corn Borer Ostrinia nubilalis (Hübner 1796) from Scandinavia

European Corn Borer (ECB, Ostrinia nubilalis) is among the main pests of maize in Europe and throughout its introduced range. Two morphologically indistinguishable pheromone races of the species exist, the so-called E-race and Z-race. In Germany the E-race is most common in mugwort (Artemisia vulgaris) whereas the Z-race occurs mainly in maize and is responsible for the main proportion of the economic damage. But both races have several alternative host plants. For example, the E-race can also occur in maize. The species has been known from Scandinavia already for a considerable time period, but no occurrence in maize was reported until recently. In 2010 larvae were found in maize at one site on the isle of Sealand, Denmark. A monitoring with Z-race pheromone traps in Denmark in 2011 did not result in any catches of ECB. In the same year however, ECB larvae were found in maize at 3 sites in southern Sweden. Larvae from 2 sites were assigned to Z-race via PCR. Independently from these finds, adult moths caught on the isle of Gotland in 2010 were also confirmed to be Z-race by PCR. This is the first evidence of the occurrence of the Z-race in Scandinavia and the northernmost find of the Z-race in Europe so far. Implications for plant protection are discussed.