Even though it was an "oddball" summer, he said the wasp population had grown dramatically again.
"We had a strange summer because it was never really warm."
Funding for the volunteer crew set up by DoC is provided by Ruapehu District Council and Horizons Regional Council.
A member of a community work team with a Corrections Department crew had to be pulled off the job in March after a worker was stung.
The crew were pulled off the work site and Raetihi Promotions was asked to remove the wasp nest before the team would return to the site.
Wasps especially like sweet foods, and compete with birds for nectar, fruit and honeydew.
Their nests are started by a queen wasp, usually underground, and their numbers increase as the summer goes on. Winter usually kills the whole nest, leaving the queen to take shelter and start a new colony the following spring.
Nests are grey and made by the wasps out of chewed-up wood fibre, softened with saliva. The larvae inside are kept at a constant temperature by the insulating paper-like material and by the movement of adult wasps, called "shivering".
Wasps can become aggressive if their nest is threatened and adult wasps stings can be dangerous.
Mr Maru said when approaching a wasp nest the guard wasps stream out in single file ready to attack.
"Sometimes if you're looking into the sun at the end of the day you can often see a V shape of wasps like little Kamikaze pilots heading home to their nest.
"It's an incredible sight."
The powder insecticide Permethrin is given to the group to exterminate the wasp nests, he said.
However, the group's labour is completely voluntary, although most people who call them make a donation.
"Donations are good because we're using our own petrol to get there.
"But mostly people are really good and appreciate us coming in ."
