IS THE POOR ESTABLISHMENT AND PERFORMANCE OF HEATHER BEETLE IN TONGARIRO NATIONAL PARK DUE TO THE IMPACT OF PARASITOIDS, PREDATORS OR DISEASE?

Heather beetle (Lochmaea suturalis), introduced in 1996 into Tongariro National Park, New Zealand to control heather (Calluna vulgaris), has established poorly and only damaged heather at one site. This work investigated whether natural enemies could be reducing heather beetle establishment and impact. No egg, larval or adult parasitism was found. Possible egg predation by a carabid beetle larvae, and occasional attacks on larvae by the native pentatomid (Cermatulus nasalis), were observed in the field. Neither the microsporidian pathogen discovered in some beetles imported from the United Kingdom, nor any other pathogenic diseases, were detected in field-collected beetles in New Zealand. It is suggested that adverse weather was responsible for a collapse in heather beetle numbers at Te Piripiri during 2002. Further efforts to redistribute heather beetle and continued monitoring of beetle numbers, impact, natural enemies and climate at release sites are recommended.