HARMONIA AXYRIDIS: A SUCCESSFUL BIOCONTROL AGENT OR AN INVASIVE THREAT?

Abstract

The harlequin ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is an aphidophagous coccinellid, native to central and eastern Asian (Kuznetsov, 1997). This predatory ladybird has been available in many countries for use as a biological control agent of pest insects including aphids and scale insects. Since 1916 H. axyridis has been repeatedly released as a classical biological control agent in the USA (Gordon, 1985). It established in the 1980s and has spread and increased in number dramatically so that it is now the dominant species of ladybird in many parts of North America (Hesler et al., 2001; Smith et al., 1996; Tedders and Schaefer, 1994). In mainland Europe it has been commercially available for both classical and inundative biological control strategies since 1982 (Iperti and Bertand, 2001) and has become established in France, Belgium, Holland, Germany, Luxemburg and Italy. It has also been released in South America and the Middle East. Harmonia axyridis has not been intentionally released in the UK, however given the proximity of the SE of Britain to the French, Belgium and Dutch coasts it was inevitable that it would arrive. In mid September 2004 a male was found in Essex (SE England). The arrival of H. axyridis in the UK has been met with considerable concern both from ecological and anthropogenic perspectives. In this chapter we address both the perceived potential problems and the possible benefits associated with the arrival of this invasive species. In addition we report on methods of monitoring H. axyridis in the UK and the initial public response to a national survey involving this alien species and the native coccinellids with which it may interact.