Forestry pests and diseases in Switzerland
A recent report published by the Swiss Federal Institute for Forest Snow and Landscape Research presents the situation of forestry pests and diseases observed in 2007 in Switzerland. It can be noted that 4 new insect species were discovered in 2007 on woody plants (Cinara curvipes, Obolodiplosis robiniae, Halyomorpha halys and Diaphania perspectalis). It is suspected that they have been introduced with trade of ornamental woody plants or wood packing material. It is also considered that climate change, and in particular temperature increase, may favour the establishment of these newly introduced insect species.
- New pest records
Ash dieback: since 2007, symptoms of dieback have been observed on ash trees (Fraxinus excelsior) in several cantons (e.g. Graubünden, Valais). Although Chalara fraxinea (EPPO Alert List) has not been identified on declining trees, it is suspected that it occurs in Switzerland.
Diaphania perspectalis (syn. Glyphodes perspectalis, Lepidoptera: Pyralidae – EPPO Alert List) was detected for the first time in Switzerland on Buxus plants in summer 2007, at several locations near Basel (zoological park ‘Lange Erlen’ in Basel, Riehen).
Cinara curvipes (Homoptera: Aphididae): high population levels were found on 1 tree (Abies concolor) in a private garden at Spreitenbach, in the canton of Aargau. This aphid of North American origin has also been recorded in several other European countries (Czech Republic, Germany, Serbia, Slovakia, United Kingdom – see EPPO RS 2008/053).
Halyomorpha halys (Heteroptera: Pentatomidae): this polyphagous pest was recorded for the first time in Switzerland at 5 locations near Zürich in summer 2007. This is also the first record of this Asian pest in Europe (see EPPO RS 2008/200).
Leptoglossus occidentalis (Heteroptera: Coreidae) was first found in Switzerland in 2002. In 2007, it was recorded in several locations in the cantons of Uri and Vaud. The EPPO Secretariat previously had no data on the occurrence of this pest in Switzerland. L. occidentalis is a pest of American origin which feeds on seeds of conifers. It can be recalled that it has been reported recently from other European countries (France, Italy, Slovenia – see EPPO RS 2007/210).
Obolodiplosis robiniae (Homoptera: Cecidomyiidae): this gall midge of North American origin was found on Robinia pseudoacacia at 4 distant sites: Agarone (canton of Ticino), Birmensdorf (Zürich), Emmen (Lucerne), and Susten (Valais), which suggests that the pest is already widespread in Switzerland. Low levels of populations were found, and inside the galls, pupae of a parasitoid wasp Platygaster robiniae (Hymenoptera: Platygastridae) were also discovered. In the EPPO region, O. robiniae was first reported in Italy in 2003 and appears to be spreading to several other countries (see EPPO RS 2008/202).
- Detailed records
Cameraria ohridella (Lepidoptera: Gracillariidae – formerly EPPO Alert List) is now widespread in Switzerland, mainly occurring in urban trees.
Ceratocystis fimbriata f.sp. platani (EPPO A2 List) mainly occurs in Ticino but has also been detected in Geneva canton. In 2007, new outbreaks were reported near Ceresio and Malcantone (Ticino).
Cryphonectria parasitica (EPPO A2 List) mainly occurs in the cantons of Graubunden, Ticino, Valais, and Vaud. Several foci have also been reported from the German-speaking part. In 2006, severe hail damage has led to an increase of the disease at Malcantone in Ticino.
Mycosphaerella dearnessii (anamorph Lecanosticta acicola – EPPO A2 List) was first reported in 1995 (see EPPO RS 95/239) at 1 site (Zollikon, canton of Zürich). It was later discovered at 2 other locations: Weesen (St Gallen) and Sarnen (Obwalden). In 2007, 4 new outbreaks of M. dearnessii were detected at Uitikon, Birmensdorf (both in Zürich canton), Neuenegg (Bern), and Bremgarten (Aargau). So far, the disease has only been found on Pinus mugo grown in parks and gardens and it has not reached forests.
Mycosphaerella pini (anamorph Dothistroma pini - EU Annexes) has only been recorded in gardens. In 2007, it was only recorded at Zumikon (Zürich canton).
Sources
Institut fédéral de recherches sur la forêt, la neige et le paysage WSL, Birmensdorf (CH). Meier F, Engesser R, Forster B, Odermatt O, Angst A (2008) Protection des forêts – Vue d’ensemble 2007. http://www.wsl.ch/forschung/forschungsunits/walddynamik/waldschutz/wsinfo/fsueb/fsub07f.pdf
Rennwald E (2008) Bestimmungshilfe für die in Europa nachgewiesenen Schmetterlingsarten. http://www.lepiforum.eu/cgi-bin/lepiwiki.pl?action=browse;id=Glyphodes_Perspectalis
Wermelinger B, Skuhravá M (2007) First records of the gall midge Obolodiplosis robiniae (Haldeman) (Diptera: Cecidomyiidae) and its associated parasitoid Platygaster robiniae Buhl ; Duso (Hymenoptera: Platygastridae) in Switzerland.; Entomologischen 217-221. http://www.wsl.ch/personal_homepages/wermelin/publikationen/2007_obolodiplosis.pdf