EPA want release of parasitoid wasp to control pest beetle

A eucalyptus tortoise beetle, Paropsis charybdis, which may be about to come under attack.

The Environmental Protection Authority is considering an application from Scion, the Crown Research Institute focused on research, science and technological development for the forest and timber industries, to release a parasitoid wasp to control the eucalyptus tortoise beetle.

"The Australian eucalyptus tortoise beetle causes significant damage to susceptible species of eucalypts. Its larvae feed voraciously on eucalyptus leaves for three weeks before pupating. Adult female beetles also feed heavily as they develop," said Dr Fiona Thomson-Carter, the EPA's general manager of hazardous substances and new organisms.

"According to the applicant, the beetle costs the forest industry $1-$2.6 million a year in chemical control. It estimates that effective biocontrol could prevent $7.2m in annual losses caused by impaired tree growth and yield attributable to the eucalyptus tortoise beetle."

Scion had claimed owners of moderately-sized eucalyptus plantations could not afford aerial spraying.

"Eucalyptus trees are grown in New Zealand as a source of products such as woodchips for paper and cardboard manufacture, lumber, and durable poles that do not require preservative treatment," Dr Thomson-Carter added.

"Scion notes around 90 per cent of tortoise beetle larvae survive into adulthood. But if a larva is attacked just once by the parasitoid wasp, survival drops to just 10 per cent."
The wasp was harmless to humans.

Scion had told the EPA New Zealand had no native beetles of the same type as the eucalyptus tortoise beetle, and no native eucalyptus species. Its laboratory tests suggested the risk to non-target native and beneficial beetles appeared to be very low.

Public submissions close on November 14.