European Wasps – Unwelcome Return Visitors
Posted on 31 March, 2015 by Connecting Country
European Wasps covering a Golden Point pear (copyright John Ellis, 31 March 2015).
Many locals have been reporting large numbers of European Wasps over recent weeks. And we are apparently not alone in this observation (see other reports here and here). According to leading entomologists, Victoria is experiencing its worst infestation of European Wasps (Vespula germanica) in about 20 years. This introduced species first become established on mainland Australia (near Melbourne) in 1977, and was relatively abundant through the 1980s up to the mid-1990s. However, until this current summer and autumn period, they have since been uncommon to rare. It is thought that the combination of a mild winter followed by a mild summer has allowed them to come back in early 2015 with a vengeance. In most years, 90% of colonies do not survive Victoria’s cold winters.
(c) Copyright John Ellis
If a colony is disturbed, they can sting humans and pets repeatedly. A number of people have also accidentally swallowed wasps when drinking sweet drinks or eating fruit or sugary foods, leading to stings in mouth or in the throat. They have also been known to destroy grape crops and will attack native insects and other local animals. It was often described as a ‘Killer Wasp’ soon after its arrival in Australia, but thankfully so far no human deaths have been recorded in this country (according to the Museum of Victoria website).
While there are traps available that can allow you to kill a few hundred individual wasps, this is unlikely to make a big difference overall, as a typical wasp colony will often have between 30,000 to 100,000 wasps. To make a lasting impact, the nest needs to be eradicated. Most wasps will forage within 50 to 250 metres of their nest. Nest colonies can be either on the ground in a range of concealed sites (e.g. uncovered compost heap, a hole in ground, piles of rubbish) or above the ground (e.g. in the roof or wall cavity).
The Museum of Victoria website contains a wealth of information about European Wasps, including:
- Their identification (click here)
- Their Impacts (click here)
- Their Life History (click here)
- Their Nests (click here)
- First Aid treatment (click here)
- Control Measures (click here)
The Mount Alexander Region Subspecies? (From www.horrorfilmhistory.com)
While control can be attempted by anyone (and there are instructions on the Museum website about how to do this), the use of professional exterminators is strongly recommended due to the risks involved.
It’s a bit worrying that they’re in the ground where you might dig- happened to a friend or in open composts. We should all put out traps when the queens are around using meat I think. I forget when it is but if many people did this maybe we could knock them back a bit. Anyone know what season it is for queens going about looking for a nesting place? End of winter???
Hi Christine,
This might take a bit more research and investigation.
There is nothing on the Museum of Victoria website that I could find about the typical flight times of the Queen bees, nor whether they can be targeted as a method of control. Their website does seem to indicate that both above ground nests (http://museumvictoria.com.au/wasps/aboveground_control.asp) and in ground nests (http://museumvictoria.com.au/wasps/inground_control.asp) are best controlled by killing all inhabitants of a colony using specific pesticides in a particular manner.
The Museum of Vic website was the best source of information I could find about European Wasps in SE Australia, but I would love to hear of other useful sources that people know about.
Chris
I came within a foot of standing on a nest in the ground while controlling weeds at the Castlemaine Botanic Gardens Flora and Fauna Reserve the other day. We marked the area with pink flagging tape. Interesting that the wasps apparently survived last winter when we had some very cold mornings (down to -6c).
That does seem strange about the cold weather. Maybe it requires a sustained period of cold days, rather than a one-off super-cold day?
Doesn’t anyone know if there is any effort in progress to permanently eradicate European wasps?
Hi Dee,
I am not aware of any such efforts. According to what I read on the Museum of Victoria website, they are now a permanent fixture in SE Australia, and are beyond outright eradication using the available techniques. Perhaps the best we can hope for is the manage their numbers and spread. Maybe the CSIRO or similar research institute are working on a biological control that could lead to a more permanent solution?
Chris
The wasps are actually making nests in our rammed earth walls. I reckon those with mud brick houses will be experiencing the same problems.
Fantastic and love the humour!