European wasp
Summary sheet Introduction Pest status Potential for introduction and distribution in Western Australia Annual activity Late Spring Mid Summer - mid Autumn Late Autumn - mid winter Mid Winter - late Spring Surveillance activities Public enquiries What to look for Identification/confirmations Trapping Trap locations Trap installation Inspection and servicing times Wasp discovered in trap Recording and reporting Positive European wasp identification Location of nest Destruction of nests Appendix 2. Farmnote: European wasps
3. APB Infonote: European wasp
4. Farmnote: Paperwasps and European wasps
Summary sheet: European wasp
Surveillance for European wasps relies greatly on the public reporting activity.
What to look for
- The wasps are brightly coloured yellow and black.
- They look like a bee and also fly with their legs held up.
- The antennae on their heads are entirely black.
- Nests are usually underground, in a hollow tree or in roof or wall cavities.
- Wasps are usually most noticeable near the small entrance of their nests.
- The multiple honey-comb layers of the nests have an outer layer of papery material.
- European wasps are unusual as they feed on meat products.
Identification/confirmation European wasp leaflets (Appendix 2-4) should be sent to the person reporting the wasp as confirmation of identification and as a form of education.
Trapping
- The European wasp trap is a modified fruit fly trap. Cones in the entrances to prevent wasp escape.
- Current bait is Sure-fireŽ Yellow Jacket Bait.
- Traps are most effective where alternative food sources are scarce.
- Install traps in commercial and/or industrial areas and freight end-points.
- Traps should be installed on a 1 km grid pattern.
- Place traps 1-2 metres above ground, preferably in a tree.
- Place trap in an inconspicuous position to avoid vandalism.
Inspection and servicing period 1st December – 30th June
Inspection and servicing frequency Every two weeks over the inspection and servicing period
Wasp discovered in trap; Contact Pest and Disease Information Service
Department of Agriculture and Food
Western Australia
South Perth WA 6151
Tel 1800 084 881
European or German wasps, Vespula germanica, are native to Europe and have established in the USA, South Africa, New Zealand and eastern Australia (Appendix 1).
In Europe, these wasps have a defined annual cycle with nests established in early summer by single fertilised queens. These founding queens have to survive winter, excavate a hole, collect wood fibre and construct a nest, lay eggs, gather food (primarily insects) and rear the initial brood to adulthood. These first workers then take over the responsibilities for nest construction and food collection freeing the queen to concentrate on laying eggs. This initial phase is so difficult that the failure rate is greater than 99%. Nests reach a size of 2-3,000 workers before the onset of winter triggers a release of drones and queens. The nests die out during the severe winters. In Australia and New Zealand, the milder winters can allow the nests to survive over winter. These nests can be re-queened by multiple fertilised queens. Because these nests are already established they grow in size at a much greater rate. These over-wintered nests can attain sizes of 3-4 metres across and contain hundreds of thousands or even millions of wasps.
European wasps, Vespula germanica and Vespula vulgaris, are primarily considered urban nuisances but they have human health, agricultural and environmental impacts.
They are attracted to meat and sweet drinks and can interfere with outdoor activities such as BBQ’s. The cost of controlling European wasp nests in urban areas of the eastern States in 1992 was estimated at $600,000. Pest Control Operators (PCO’s) charge between $50 and $350 per nest for removal. In Adelaide alone, more than 8,000 wasp nests were destroyed during the 1997/98 season.
European wasps are a serious pest of the apiculture industry, attacking bees and killing and robbing hives. The wasps are also a pest of the soft fruit industry and are considered a serious pest of grapes in California. In Israel, they have even been reported stripping flesh from cow’s teats.
Through sheer numbers, the predation of European wasps on native insects can be deleterious but they can also affect native animals (including birds) through competition for food. Tourism can even be affected. National parks in the USA and New Zealand have been closed due to high European wasp activity.
From a human health aspect, European wasps are capable of causing death (no deaths have been
recorded in Australia) either through allergic reaction to stings or via massive attacks when nests are accidentally disturbed. The cost to the community for treatment of victims can be significant.
Potential for introduction and distribution in Western Australia
European wasps are widely established in Victoria, New South Wales, Tasmania and South Australia. Every year nests of European wasps are established in Western Australia as a result of fertile European wasp queens being transported into W.A. in merchandise imported from the Eastern States.
The first nests were discovered in W.A. in 1977 and since that time Agriculture Western Australia has run very effective publicity campaigns in an attempt to help prevent wasps becoming established. To June 1998 a total of 334 wasp nests. Most of these nests have been in the Perth metropolitan area but 22 have been found in country districts (Albany 17, Kalgoorlie 3, Geraldton 1 and Eucla 1).
Potentially, European wasps could establish anywhere in W.A. south of the Tropic of Capricorn. Except for the extreme south-west (Albany – Bunbury), nest establishment is likely to be limited to urban areas where additional water supplies are available.
Late Spring
(November –December): ‘Hibernating’ queens emerge and begin to establish nests. Queens may be seen on power poles and other sources of timber, scraping the surface for wood fibres for nest construction.
Mid Summer - mid Autumn
(January to March): Nests are established and worker wasp numbers increase rapidly. Workers can be seen on poles scraping for wood fibre and may settle on meat products and pet food.
Late Autumn - mid winter
(April – July): Drones and queens are produced. Queens mate and then leave the nest to ‘hibernate’ in cracks and crevices over winter.
Mid Winter - late Spring
(August – October): Queens in ‘hibernation’. Nests decline in activity and usually die.
Surveillance for European wasps relies almost entirely on the vigilance of the public. Although there are traps available, and in limited use, these are not considered effective.
(Appendix 2 & 3)
- European wasps are brightly coloured yellow and black – there are no other colours.
- They are squat in appearance, much like a bee, but slightly larger than a bee.
- They also fly like bees, with their legs held up close to their bodies.
- The antennae on their heads are entirely black.
- The nests are concealed and are usually underground, in a hollow tree or in a roof or wall cavity in a house.
- The multiple honey-comb layers of the nests are covered by an outer layer of papery material. By February, the nests are the size of a basketball or bigger.
- Wasps are usually noticeable near the nest entrance where streams of wasps may be seen entering and leaving a small hole (usually the size of a 50 cent piece) - especially on warm days.
- European wasps differ to other wasps as they feed on meat products.
Yellow and black is the most common colour combination in the wasp world. There are many native wasps that have these colours. However, the combined features of yellow and black colouring, bee-size and antennae which are entirely black is not common and, wasps reported with these characteristics, should be investigated further.
Paper wasps
In the south-west of W.A. there are 2 species of paper wasp which are commonly mistaken by the public as being European wasps. The yellow paper wasp, Polistes dominulus, (Appendix 3) is very similar to the European wasp in colour but has antennae that contain yellow or orange markings as well as black. Their nests are also distinctive, being a single ‘honeycomb-like’ layer which is usually horizontal. If ‘honeycomb’ cells can be seen it is unlikely to be a European wasp nest which has an outer covering. The common paper wasp, Polistes humilis synoecus, has a nest similar to the yellow paper wasp but has brown, yellow and black markings.
There are two types of errors that can occur when identifying suspect wasps over the ‘phone.
Type 1 errors are when you identify the wasp as being a non-pest when it is actually a European wasp.
Type 2 errors are when you identify the wasp as being European when it is not.
The cost of a Type 1 error is large because the nest can continue to survive to maturity and release hundreds or even thousands of queens possibly leading to the establishment of European wasps.
The cost of a Type 2 error is the time and vehicle expense associated with a negative result following a trip to the location to confirm the identity of the wasp. Type 2 errors are far cheaper and so inspections and confirmations are recommended where the wasp cannot be identified with any certainty (eg the nest cannot be seen or the antennae or leg positions not able to be observed by the caller).
With every wasp inquiry, a European wasp leaflet (Appendix 1-3) should be sent to the person reporting the wasp to confirm the identification and as a form of education.
European wasp traps are based on the standard fruit fly trap but are modified via the fitting of special ‘cones’ in the entrances to prevent wasp escape. Various baits have been tried but the current one in use is Sure-fireŽ Yellow Jacket Bait which is imported from the USA. This bait is meat based (liver) but contains a preservative to prevent putrefaction.
The traps only appear to be effective where alternative wasp foods are scarce. As European wasps tend only to establish in association with human habitation and are primarily introduced with merchandise imported from the eastern States, the best places to install the traps are in commercial and/or industrial areas and freight end-points (terminals, trucking yards and ports). The traps should be installed on a grid pattern no more than 1 km apart.Traps should be installed at 1-2 metres above the ground and preferably in a tree as European wasps often forage for insects in tree canopies. If available, choose a conifer in preference to other species. The trap should be suspended by a single wire support and be free from contact with other branches so ant access is limited. The ‘Sure-fire’ bait satchel is cut in half and one half is placed in each trap with the cut end opened out to allow the odours to freely circulate.The trap should be placed in an inconspicuous position to avoid vandalism. Clear notes and directions must be included on the work sheets to aid in its location.
Inspection and servicing times – 1st December – 30th June
Servicing consists of changing the bait lure every 2 weeks. The trap will only need replacement if it is damaged.
Wasp discovered in trap
Carefully remove the wasp/s and place them in a plastic vial. Using a pencil, make a label with the trap number and location details, date and your name. Place it in the vial with the specimens.Send to:
Pest and Disease Information Service
Department of Agriculture and Food
Western Australia
South Perth WA 6151
Tel 1800 084 881
Recording and reporting
Inspectors must carry run books on their trap inspections.
Advise Peter Davis, Social Insect Research Section at South Perth immediately. Submit specimens via ‘overnight express post’ to Peter Davis for confirmation.
Nests can be located by observing wasps and determining the direction they take just after they take off from the lamppost or food they were on. If this can be done from several different points the approximate location of the nest can be determined and then closer observation can detect higher wasp densities leading to discovery of the nest entrance (in theory at least).
Small portions (~2-4cm square) of fresh fish can be nailed to posts where wasp activity is suspected as a means of detecting wasps where activity is low.
Once nests have been located, advise Peter Davis at South Perth. Nest destruction is a specialist activity and should not be undertaken before consultation with Mr Davis.
Appendix 1 World distribution of European wasp.
