Wasps are making a comeback after two years of low numbers, but the Department of Conservation is fighting back.
Landcare Research ecologist Dr Richard Harris said early indications were that wasp numbers would be high this summer, because of a warm, dry spring and low populations last year, which produced better-quality
queens.
Reports from throughout the country - including the department's wasp project at Lake Rotoiti, in Nelson Lakes National Park - were that wasp numbers were already high for this time of year.
Heavy rain could still flood nests while they were small and reduce numbers, he said.
The department's ranger for the Rotoiti Nature Recovery Project, Matt Maitland, said wasp poisoning in the area would start in the next few weeks and would cover 800 hectares.
The critical threshold of wasp numbers had been reached earlier than in other years, which showed that the population was building faster.
The poisoning took eight department staff a day to complete and was 99 per cent effective overnight, he said.
Worker wasps carried the poison back to nests and distributed it to the whole population.
Wasps are a pest because they kill native invertebrates and compete for food with tui, bellbirds and kaka.
Mr Maitland said reducing wasp numbers also benefited visitors to the area.
"It turns a picnic into a pleasure rather than a nightmare."
- NZPA
