|[Note Guidelines] Photographer's Note|
|Chrysolina americana (Linnaeus, 1758) Rosemary Beetle|
The rosemary beetle (Chrysolina americana) devours the leaves of rosemary, lavender, thyme, sage and some other related plants. It is an attractive 8mm long metallic green beetle with purple stripes on its wing cases and thorax. The beetle is a native of southern Europe that has become an established pest in Britain since the 1990s.
It was first found living out of doors in the UK at RHS Garden Wisley, Surrey in 1994 but this population soon died out and it was not seen again at Wisley until 2003. By 1998 established colonies of the beetle had been discovered near Londonís Waterloo Station and Winnersh, near Reading, Berkshire.
In 1999 the first enquiry concerning rosemary beetle was received by the RHS Membersí Advisory Service from a garden in Weybridge, Surrey. By the end of 2005 the beetle had become widespread throughout London and surrounding areas, and had become one of the top 10 most frequent pest enquiries made to the RHS Membersí Advisory Service. Rosemary beetle is now widespread in England and has been found in parts of Scotland, Wales, Northern Ireland and the Irish Republic.
The soft-bodied grubs are greyish white with five dark longitudinal lines; fully grown larvae are 5-8mm long. Sausage-shaped eggs, 2mm long, may be found on the underside of the leaves from early autumn to spring.
Size & characteristics:
Attractive, 8mm long, metallic green beetle with purple stripes. The larvae are grey with darker stripes and up to 8mm in length. Can be found feeding on the leaves of rosemary, lavender and related plants.
CONCLUSION OF THE PEST RISK ANALYSIS
This is a little known pest of rosemary and lavender. Its native range covers much warmer and drier climates than that of the UK. Previously only adult beetles have been found in the UK. This PRA was initiated with the first finding of larvae. It is unusual to find larvae during early summer, in its native range they are normally found in the autumn. There was no obvious import connection to the beetles finding on this occasion and they may have been present for some time, indicating that establishment could occur in the UK at suitable sites.
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