De invasieve Oost-Amerikaanse kersenboorvlieg Rhagoletis cingulata in Nederland (Diptera: Tephritidae).

The invasive American Eastern Cherry Fruitfly Rhagoletis cingulata in the Netherlands (Diptera: Tephritidae) In 2003 the European Invertebrate Survey - Netherlands, on request of the Plant Protection Service of the Netherlands, conducted a survey of the distribution and phenology of the American Eastern Cherry Fruitfly Rhagoletis cingulata (Loew, 1862). The focus of this survey was the province of Zeeland, because the first records stemmed from this province (Van Aartsen 2001). Three populations were monitored with Pherocon am yellow sticky traps (without attractant). Two of these populations were on the peninsula of Walcheren (‘Zandput’ and ‘Oranjebos’, both near the town of Vrouwenpolder) and one on the island of Schouwen (‘Het Zeepe’, near the town of Burgh). This survey was supplementary to the surveys of the National Plant Protection Service, conducted in commercially grown cherry orchards in 2003-2006. In this paper an overview is given of the results of these surveys, supplemented with a few scattered records of others. Rhagoletis cingulata is a well-known and severe pest in commercially grown cherries in North America. This originally Nearctic species is listed as a quarantine species in the European Community (Annex 1a1 of the Council Directive 2000/29/ec) of which introduction into, and spread within, all member states should be banned. In the Netherlands R. cingulata should be regarded as an established species that has been introduced by man and which has sustained populations for more than ten years. Extermination of this species, as required by eu legislation, is therefore useless. Meanwhile several eu member states have asked the European Committee to remove this species of the quarantine list. Given the distribution of its host Prunus serotina in the Netherlands it is to be expected that the actual distribution of R. cingulata is much wider than presented in the distribution map (fig. 18). Moreover, it is discussed that it is probably able to shift to other hosts, so that it might even spread over a yet larger part of the Netherlands. All given known (potential) hosts are nonindigenous species in the Netherlands and therefore mostly ignored by entomologists, probably causing species like R. cingulata to be overlooked. The phenology of the population at ‘Zandput’ differs greatly from both other populations (fig. 10 versus fig. 9 & 11 ). Possible explanations are an intrinsic (genetic) difference between the populations or the presence of a second species: the American Western Cherry Fruitfly Rhagoletis indifferens Curran, 1932. This has to be investigated further. The Pherocon am yellow sticky traps pose a good method for monitoring the phenology of R. cingulata, provided the host plants in which they are placed are chosen carefully. A welldeveloped population seems to be necessary, and the traps should be placed within the treetop and free from branches. The only host plant of R. cingulata in the Netherlands reported thus far is Prunus serotina. A single specimen was swept from Sorbus aucuparia, but it was probably coming from an adjacent P. serotina. Extensive examination of several other potential hosts yielded no proof of reproduction of R. cingulata on other hosts than P. serotina.