Experts believe spring weather plays a part in determining the wasp population, reports PHILIP ENGLISH.
Wasp numbers in the top half of the North Island are low for the sixth summer in a row.
But council pest control officials are not so sure that the wasp menace will remain low through the season, which peaks in March and early April.
Numbers are also lower than usual in the worst part of the country for wasps, the South Island beech forests, which can be home to up to 18 billion wasps in a season.
But the alien invaders still pose a threat to native birds and insects by taking their food - honeydew that forms on forest trees.
Dr Richard Harris, of Landcare Research's wasp programme, said mathematical modelling based on the last wasp season and spring weather patterns had predicted that numbers would be low this year.
"In the the past two years around the Nelson lakes, we have had quite low wasp densities and it seems to be heading that way again.
"There will be the odd hotspot where there will be a lot of nests in one particular area and people will have problems. That happens every year, but generally we are expecting low numbers."
Dr Harris said spring weather seemed to have the greatest impact on wasp numbers. Queens had difficulty establishing nests if they kept being flooded out by rain.
Numbers of common wasps peaked in the beech forests in the late 1980s and early 1990s, possibly the result of a quick rise in population soon after the wasp established itself in the country.
Common wasps look similar to German wasps which arrived first - in packing cases during the Second World War.
"The levels are cycling up and down from year to year," said Dr Harris, "but we haven't got to those extreme days when everyone was wondering what had hit us."
Dealing with wasps
Regional councils can advise householders about dealing with wasps.
Dealing with wasp nests is best attempted when temperatures drop at night.
Use insecticide powder or pour diesel into the nest opening.
The next step is to block off the opening to the nest.
It is best to be fully clothed and for lighting use a red-coloured torch.
If the wasps become disturbed, retreat.
To avoid being stung during the day keep a look out for wasps flying to their nests. Detour around them. If attacked a quick sprint of about 20m should be enough to escape. The venom in wasp stings stimulates other wasps to attack.
Wear light light-coloured clothing.
Wasps, bees and bumblebees direct their attacks against dark colours, particularly blue.
If a wasp settles on you do not panic. It will usually fly off in a few seconds.
People who have been stung several times might think they have become immune - but the next sting might result in a dangerous allergic reaction.
For more information visit the Landcare Research website.
Links:
Landcare Research
Wasp numbers down but threat remains
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