THAUM
- 1. 1 Caterpillars of the Pine Processionary Moth Thaumetopoea pityocampa (Denis & Shiffermüller) (Lepidoptera: Thaumetopoeidae) overwintering in the Britain on imported Pinus sylvestris L. J C Starzewski Central Science Laboratory MAFF, Sand Hutton, York Y04 1LZ Caterpillars of Thaumetopoea pityocampa were found on pot grown pine saplings on 26 April 1995 on a commercial nursery in Buckinghamshire by a Plant Health and Seeds Inspector (PHSI) during a routine monitoring visit. The specimens were forwarded to the Central Science Laboratory where they were identified based on the following description given by Carter, (1984); head black; body bluish-black, whitish-grey below spiracular line; lateral and ventral surfaces with tufts of white secondary setae; dorsal surface with tufts of reddish secondary setae arising from reddish brown verrucae. The saplings had been imported from Italy in December 1994. This species does not occur in Britain, therefore it is assumed these specimens had been imported with the saplings and had successfully overwintered. The caterpillars of T. pityocampa are a serious pest of Pinus spp. and Cedrus spp. in continental Europe causing extensive defoliation of the host which can result in death. In Italy one of the main food plants for the caterpillars is P. sylvestris (Masutti & Battisti, 1990). In addition the caterpillars pose a threat to public health as they are covered in urticaceous hairs which can cause serious irritation to people and domestic animals, with numerous such cases occurring each year (Arditti et al, 1988).
- 2. 2 The recorded range of this species extends from south-central Europe to north Africa. However in recent times it has extended its range further north in France having been found in almost all departments below a line connecting the north coast of the Côtes-du-nord in the west through Dijon to Geneva, Switzerland in the east (Bouhot & Levy, 1990). The timing of the life cycle varies slightly between countries but is generally as follows. Adult moths lay large numbers of eggs between June and September which hatch after five to six weeks. The resulting caterpillars are gregarious and live within a communal nest which is approximately the size of a football. The nest is constructed from silk and is usually armed with shed urticating hairs and is located in the branches of the host. At dusk the caterpillars leave the protection of the nest to feed on the surrounding foliage. They overwinter in these nests, occasionally coming out to feed during mild weather. The following year between February and June the caterpillars start displaying the behavioural characteristic that has given rise to their common name; they form processions consisting of a number of caterpillars all travelling together usually in single file. Between February and July the caterpillars pupate underground where they can remain for up to three years before emerging as adults. Adults occasionally occur in the southwest of Britain as summer migrants (Tim Winter, Forestry Commission, pers. comm.). This species was recorded in Kent Between 1872 and 1874 (Heath & Maitland Emmet, 1979) but died out despite the attempts of enthusiastic amateur entomologists of the time to spread this species (Allan, 1943).
- 3. 3 Because of the pest potential of this species the infested stock was treated to kill any remaining caterpillars or pupae hidden in the soil. Further monitoring has been undertaken but no further occurrences have been recorded. Climatic change and increasing international trade could in future increase the chance of this species becoming re-established in Britain. Any findings should be reported to the PHSI via the nearest Ministry of Agriculture, Fisheries and Food office. Acknowledgments I would like to thank Tim Winter of the Forestry Research Station, Farnham, Surrey for his help and the useful information he provided and my colleagues Dr. Christopher Malumphy and Mrs. Sue Hockland for their editorial comments. References Allan, P. B. M., 1943. Talking of moths, pp. 240-244. Newtown, Montgomery. Arditti, J., David, J M., Jean, P. & Jouglard, J. 1988. Accidents provoques par la chenille processionnaire du pin en Provence. Journal de Toxicologie Clinique et Experimentale. 8: 4, 247-251. 3 ref. Bouhot, L. & Levey, A., 1990. La Chenille Processionnaire du Pin. In: La Santé des Forêts 1990. Ministere de l`Agriculture et de la forêts.pp 11-13. Paris. France. Carter, D. J., 1984. Pest Lepidoptera of Europe. Dr W. Junk, The Netherlands. 431 pp. Heath, J & Maitland Emmet, A., 1979. Moths and Butterflies of Britain and Ireland. Vol. 9. Curwen Books. 228 pp. Masutti, L. & Battisti, A. 1990. Thaumetopoea pityocampa (Den. & Schiff.) in Italy. Bionomics and perspectives of intergrated control. Journal of Applied Entomology 110: 3, 229-234. 20 ref.