Invasive alien species in Switzerland - Schweizer ...

An inventory of alien species and their threat to biodiversity and economy in Switzerland FOEN 2006 80
poorly known insects, and it is possible that other milichiid members of the Swiss
fauna are also of exotic origin (B. Merz, pers. comm.)
Exotic mosquitos (Culicidae) represent a major threat to human health worldwide. The
tiger mosquito, Aedes albopictus, was found in Switzerland for the first time in the
Ticino in 2003 (see Fact Sheet). Besides causing human nuisance through its bites, A.
albopticus is also a potential vector of various illnesses. In Asia, its region of origin, it
is a natural vector of dengue fever and other arboviruses, as well as filaria for both
human and domestic animals. In North America, it is a vector of the West Nile virus.
4.6 Hemiptera
This order probably encompasses the highest number of exotic pests worldwide. Small
Hemiptera, particularly aphids, scales, whiteflies and psyllids, are very easily carried
around the globe on plant material. Many are pests of worldwide distribution and it is
sometimes difficult to assess their region of origin. Among the cosmopolitan species of
doubtful origin and listed as exotic in Switzerland, for example, are the aphids Myzus
persicae, Aphis gossypii and Cinara cupressi, the whitefly Bemisia tabaci, and the
scales Dynaspidiotus britannicus, Quadraspidiotus pyri and Planococcus citri. Many
other cosmopolitan species are not included in this list because they are supposed to be
of European origin (e.g. the aphids Acyrthosiphon pisum, Brevicoryne brassicae and
Rhopalosiphum padi), although their origin is unclear and the possibility that they
entered Switzerland a long time ago cannot be ruled out.
Another problem, particularly prevalent in Hemiptera, is the high number of tropical or
subtropical pest species introduced into greenhouses with their host plants. The most
abundant species have been included in the list because there is no doubt that they have
become established in Switzerland in indoor conditions. For example, the aphid Aphis
gossypii, the whiteflies Bemisia tabaci and Trialeurodes vaporarium and the scale
Planococcus citri are recurrent problems in protected crops and plants in Switzerland.
Many other tropical and subtropical species are occasionally reported from greenhouses
and indoor plants, but it is difficult to say whether their presence results from a
permanent establishment or from regular introductions. In addition to those species
included in our list, Kozar et al. (1994) mentions several species of scale insects that
have been recovered from greenhouses and indoor plants in Switzerland. Interestingly,
three of these scale species previously known only from greenhouses (Diaspidiotus
distinctus, Coccus hesperidum and Icerya purchasi) are now found established in the
field (Kozar et al., 1994). Other ‘greenhouse’ Hemiptera of exotic origin and not
mentioned in our list are bug species of the genera Orius and Xylocoris (Anthocoridae),
commonly used as biological control agents against thrips, spider mites or aphids.
Many hemipteran species in Switzerland have migrated from neighbouring countries,
especially the Mediterranean region. In most cases these have probably been introduced
with their host plant. For example, most Psyllidae and Triozidae, included in the
list feed specifically on plants of Mediterranean origin which are used in Switzerland
Advisors:
Daniel Burckhardt,
Naturhistorisches Museum Basel
(Psyllina); Gerolf Lampel, Pensier,
and Yves Gonseth, Centre Suisse
de Cartographie de la Faune,
Neuchâtel (Aphidina); Ralf
Heckmann, Konstanz, Germany
(Heteroptera)