New biocontrol approved in battle against beetle

Paropsis charybdis or eucalyptus tortoise leaf beetle.

No need to unleash the dragons. A tiny wasp, Eadya daenerys, can now be used in New Zealand to combat the destructive eucalyptus tortoise beetle (Paropsis charybdis).

A decision-making committee appointed by the Environmental Protection Authority (EPA) has approved an application to release the parasitoid wasp in New Zealand.

This follows public submissions, and a public hearing earlier this year.

Eadya daenerys stinging a Paropsis charybdis larva.

The application was lodged by Scion, the Crown Research Institute focused on research, science and technological development for the forestry and timber industries.

EPA general manager of hazardous substances and new organisms, Dr Fiona Thomson-Carter says, Eucalypts are an important component of our forestry industry; and in the landscape gums provide shelter, floral nectar resources for birds and bees, erosion control on steep land, and increased biodiversity.

"The Australian eucalyptus tortoise beetle causes significant damage to susceptible species of eucalypts, or gum trees.

"The deliberate use of natural enemies to reduce pest populations — known as biocontrol — can be a very cost effective and environmentally sustainable method of combatting pests, and reduce the need for chemical insecticides.

"The applicant estimates effective biocontrol by E. daenerys could prevent $7.2 million in losses per year from the eucalyptus tortoise beetle affecting tree growth and yield," she says.

New Zealand has no native beetles of the same type as the eucalyptus tortoise beetle, and no native eucalyptus species. Laboratory tests by Scion suggest the risks to non-target related native and beneficial beetles appear to be very low.

The wasp, which grows to just 6-10mm long, is harmless to humans.