What to do about wasps? They can be a real problem for beekeepers as they rob bees and larvae from the hive to feed their young on, as well as steal honey to eat themselves.
For others, the wasps pose a problem when they get in the house or potentially from stings, so, what do we do??
First off, wasp stings do not have a barb like bees, meaning they can sting again and again. Also the sting can penetrate more than a bee sting so you need to be more careful with, and how, you approach removing the nests.
Secondly they are quite aggressive and will chase you so make sure you are wearing adequate protective clothing.
Wasps prefer a warm, dry place close to water and a food source.
- Common wasps generally start in an existing hole, such as a mouse nest, rotten stump or under the roots of a large tree.
- German wasps make a paper ball either in a hedge, tree or under the eves of houses (sometimes in the roof too).
Both construct their nests in a similar fashion from chewed up wood, a spherical outer with layers of comb inside.
Common wasps will generally only last a season in North Canterbury, where as German wasps can survive the winter if it is mild or they are well protected and have a ready source of food, like a beehive. The nests that do survive a winter will be much, much bigger the second season with and even more in the third. Until recently New Zealand had the record for the biggest wasps nest, coming from Waimakau in 1963, it measured 3.7M long and 5.5M in circumference.
If you find a ground based nest it is best to wait till dark, then use something like "Carbaryl" powder at the entrance, the wasps will track the powder inside and kill the nest. Alternatively you can pour petrol down the hole, then block the entrance up totally and the fumes will kill the nest quite quickly. DO NOT light the fuel. There is a story of a farmer finding a nest in his hayshed, he used petrol but then decided to "light 'er up" and the whole shed detonated, very fortunately he was not injured but the shed was a right off.
If you cannot find the nest you can use a bait station with some fish based cat food, leave it out for a couple of days till the wasps get used to eating it then put a few drops of "Frontline" or similar on the food, the wasps will take it back to the grubs and it will kill them. Make sure no pets can get at the station.