Apparently Waikawa Beach lies at the southern end of the range of the Sydney golden wattle — an acacia that can take over dunes, crowding out other plants, leads to sand blowouts and releases allergens that affect hayfever sufferers. It also creates substantial fire risks. That’s why Horizons Regional Council has applied to import and release a bud-galling wasp to control the spread:
The wasp, which spent most of its life inside the plant and only about three days outside, laid its eggs in the flower buds, which prevented flowers forming and seed production, [Horizons Regional Council biosecurity and biodiversity manager Craig Davey] said.
“It’s perfectly tuned for this plant and so when a flower tries to grow, it can’t, because the wasp has an egg that means a plant puts all its energy into stopping this insect, so the plant ends up not producing seeds.”
Listen to the 5 minute Radio NZ interview: Proposal to introduce ‘friendly’ wasps to Manawatu-Whanganui. Waikawa Beach is mentioned at approx 1 minute 50 seconds from start.
According to the item, Proposal to introduce new wasp to Manawatū-Whanganui:
Since it was introduced, the Sydney golden wattle has become widespread throughout coastal areas of the North Island, and is considered a threat to biodiversity and to the conservation of dune and other ecosystems.
While the wasps would not remove the plant, stopping the spread of Sydney golden wattle was essential because it invaded native plant communities and was a fire risk, Davey said.
The Environmental Protection Authority, which is considering the application, is asking for submissions to be made before midnight on 30 September, 2022.
Many thanks to Stephen Betts for noticing this item and drawing it to my attention.