A successful trial has taken the sting out of wasp control at a reserve near Whangarei used often by school groups and the public.
In February, the Tangihua Lions Lodge Trust trialled a recently developed New Zealand product called Vespex, the first time it has been used in Northland.
The hit rate was phenomenal, trust chairman Gerald Mannion said.
"The trial was very successful and we will extend the programme and implement it annually. We have never been able to control the wasps, now we can," he said.
The lodge has accommodation and facilities for large group stays and access to tracks, streams, kauri stands and other natural features in the surrounding Department of Conservation land in the Tangihua Ranges.
But wasps were causing such a problem last year one school group counted 27 stings among pupils in a week. Another school recorded one pupil being stung 17 times.
Department of Conservation workers and pest control volunteers have also fallen victim to the wasps which have created nests in holes in the ground, banks and trees.
Mr Mannion said that once while he was talking to a teacher at a camp, three children were stung as they walked past "a notoriously bad spot" on a bush track close to the lodge.
"Some schools in the past would pull out or would not use the tramping tracks because of the problem," he said.
The trial required Department of Conservation (DoC), Ministry of Health and Northland Regional Council approval, and strict methodology, including before and after nest inspections and wasp counts. Cat food and sardines - high protein bait which wasps but not bees are attracted to - were used in 220 stations set 50m apart, just off the most commonly used tracks.
During and after the trial 15 nests were monitored. Eleven of them were rendered inactive, one showed significantly reduced wasp numbers coming and going and three stayed relatively the same, although the latter were either further from the bait stations or close to bigger nests and may have been new satellite nests.
The trust received a grant of $8600 from the Mid Western Lions Club to carry out the trial and will now explore other funding possibilities for ongoing wasp control.