Rats can transmit diseases, contaminate food and utensils and damage buildings by chewing conduits and wiring. The two most common types of rats that live in suburbs are the black rat and the brown rat. Both of these species were introduced from Asia and have a well known history of carrying pests and diseases. Brown rats tend to burrow and build nests around the foundations of buildings. Black rats tend to nest in roofs.
In Australia we also have two native rats know as the Bush Rats and Water Rats. Both are protected species and it is illegal to harm them. They are nocturnal and very timid and unlikely to live in urban areas.
Signs of rodent activity Rat prevention and removal
The following may be signs of rodent activity:
- Droppings (12mm to 18mm long)
- Debris such as snail shells with the sides eaten out, almond shells, cape lilac berries, bones etc left in the corners of sheds, under homes and in secluded spots
- Signs of fruit and vegetables having been eaten
- Greasy rub marks along paths
- Burrow holes around buildings
- Signs of gnawing damage
- Pet dogs, cats, birds, being more excitable than usual
- Squeaking, gnawing or movement noises in walls, cupboards, ceilings and under floors.
The following are tips to prevent or get rid of rodents:
- Store firewood away from the sides of sheds and fences and keep it well clear of the ground
- Regularly remove garden waste and disused materials
- Remove fruit and nuts from trees or vines at the end of the season
- Block holes and other access points around buildings
- Keep pet food dishes clean and store bulk pet food supplies in sealed containers
- Rubbish bins and compost containers should be well-maintained and free from holes
- Don’t compost meat scraps
- Trim trees away from gutters, patios and pergolas
- Encourage neighbours to remove excess rubbish from their property.
Poison baits are the most successful way of destroying rats. The City's Environmental Health Branch supplies a limited quantity of rat poison for residential premises (but not commercial or industrial premises). These can be collected from the City's Civic Centre at 61 Broun Avenue Morley.
There are approximately 30 species of mosquitoes in Western Australia. Mosquitoes are considered to be major pests and carriers of viruses, including:
- Ross River Virus (RRV)
- Barmah Forrest Virus (BFV)
- Murray Valley Encephalitis Virus (MVE).
Mosquito control program Mosquito prevention
The City's Environmental Health Branch undertakes a mosquito control program in collaboration with other local authorities and the Department of Health to implement the most effective control measures possible.
The program involves:
- Monitoring and trapping of mosquitoes
- Treatment of public areas identified as breeding sources
- Investigating community complaints
- Maintaining drainage systems to prevent water pooling.
Breeding pools of water are treated with larvicides, which either kill the mosquito larvae or prevent them from developing into adults. Follow up monitoring is undertaken to ensure the effectiveness of the treatments.
When there is an increased incidence of disease and when directed by the WA Department of Health, it may be necessary to fog using adulticides. This course of action is the least effective as it only kills adult mosquitoes and does not prevent breeding. It is also the least environmentally-friendly method of control.
Mosquito numbers can vary from year to year with about every second or third year being particularly bad. This can be caused by unusual climatic conditions such as the La Nina effect that can create unusually high tides, resulting in semi-permanent pools of water in low-lying river areas.
Under normal circumstances, these areas would dry out between tides and break the mosquito breeding cycle. These pools are capable of producing continuous breeding, covering several mosquito breeding stages simultaneously. In addition, the increased flushing by tidal action has been found to dilute the active ingredient of larvicides, thereby reducing their effectiveness and longevity.
Unusually high rainfall periods can also create higher than usual water levels and increased breeding.
In addition to the foreshore and wetland mosquito control program, the City's officers treat stormwater drains that hold water. These can cause problems when summer rainfall occurs or if sprinkler overspray runs into roadside stormwater gullies.
It should be noted that a mosquito control program will not completely get rid of mosquitoes, but aims to reduce breeding to acceptable levels.
Mosquitoes can be controlled by householders in a number of ways:
Prevent breeding around your house
- Identify and remove all stagnant water sources, (eg. pot plants, cans, bottles, containers, blocked guttering etc.)
- Make sure fish ponds and swimming pools are not breeding mosquitoes. Fish ponds should be stocked with mosquito larvae feeding fish e.g. goldfish. Swimming pools should be properly maintained and have clean, chlorinated water.
Protect your home
- Place fly wire on all doors and windows
- Make sure lids are sealed on septic tanks, soakwells and leach drains
- Ensure your sewerage vent pipe has a mosquito-proof cowl, and if it is metal, make sure
- the holes have not rusted through. Your vent pipe is usually located outside, adjacent to
- your bathroom or laundry and running up the side of the house and through the roof
- Put fly wire around rainwater tank inlets and overflows
- Cut back foliage that provides homes for mosquitoes.
- Avoid exposure at dusk and early evenings
- Wear loose-fitting, long clothing outdoors
- Use a suitable personal insect repellent.
Midge (Chironomidae) originate from a large and diverse family of flies. They are often confused with mosquitoes, however they are non-biting.
Midge larvae are all aquatic or sub-aquatic and are an important part of many freshwater ecosystems. However they often present a nuisance to residential areas situated near water bodies because they are strongly attracted to light.
What causes elevated levels of midge? What is the City doing to control midge around Lakes Brearley and Bungana?
Elevated midge numbers can be a result of various factors, including changes in climate and nutrient loads within the environment.
What can I do to control midge around my home?
To help control midge nuisance experienced by residents living near Lakes Brearley and Lake Bungana, the City in accordance with its management plan, is:
- Regularly treating midge harbourage areas with residual insecticide.
- Regularly treating known breeding sites.
- Trapping and monitoring.
- Sampling to determine the effectiveness of treatments and extent of breeding.
- Providing advice and free residual insecticide to impacted homeowners.
The City is researching and trialling additional midge control measures, including:
- Using temporary mobile light towers to attract midge and keep them in the treated areas away from residential properties.
- Deploying multiple large mobile solar powered traps around the lakes.
- Installing bat boxes within trees to encourage micro bats, which are known to consume large quantities of midge and mosquitoes each day.
The City has also recently undertaken dredging works at Lake Bungana.
- Keep windows and doors closed on sunset and early mornings during higher midge activity times.
- Place black light traps outside your property.
- Install fine mesh fly screens.
- Reduce the wattage of external lights.
- Use yellow external lights.
- Apply a (registered) residual barrier insecticide on external harbourage areas of your home.
For further information please contact the Environmental Health Branch on 9272 0648.
White Cedar Moth Caterpillars
Also known as Cape Lilac Tree Caterpillars, they can be a nuisance each year, usually around autumn. These caterpillars can invade homes by crawling over paths, walls and inside buildings.
The Cape Lilac Tree Moth is a prolific breeder and it is not unusual for a Cape Lilac Tree to have more than 2000 caterpillars feeding on the leaves.
The caterpillars go up the tree at dusk to feed and come down the trunk at sunrise to find a cool, dark place to hide.
How to deter White Cedar Moth caterpillars
The Department of Agriculture has advised that spraying trees for the caterpillar is ineffective, as they are fairly resistant to pesticide.
The best method of reducing numbers is to tie a piece of hessian (sacking) around the base of the tree affected. The caterpillars will congregate under the hessian to shelter from the light and heat of the day allowing easy removal and disposal. They can then be placed into an enclosed container and killed using a liberal dose of insecticide or physical means.
The tree bagging process may have to be repeated a number of times to reduce numbers to acceptable levels. Hot, dry weather usually kills them off naturally, as does the colder winter weather.
To stop caterpillars entering the house you can use rolled-up hessian, surface sprays or washing powder at doorways and openings.
For further information, contact the Department of Agriculture on 9368 3333.
Bees typically swarm in the spring of each year, prior to establishing new hives. Swarming is part of the natural reproductive life cycle of honey bee colonies. The swarm will often remain for a day or two while scout bees search for a new home or it may move to another location. Should a swarm decide to settle in your property:
Keep children and pets inside for half an hour or so, until the flying bees have clustered on to a bush or other object
Once the swarm has formed a cluster, usually about the size of a football, and most of the bees have stopped flying, it is safe to go outside and carry on as normal
Keep clear of the swarm until you can arrange to have it removed
Always wear footwear to protect your feet
Do not put the hose onto the swarm, throw stones at it, smoke the bees out or take similar action. These “do-it-yourself” remedies will aggravate bees, encouraging them to sting in defence.
Bees on public land Bees on private property
If you notice a bee swarm or hive on public land, such as a park or street verge and you think it may be a public danger, contact the City's Environmental Health Branch on 9272 0648.
The City will arrange for an officer to assess the situation and if it is considered a danger, a professional bee removalist or pest control operator will be sent to relocate or eradicate the swarm.
If a bee swarm or hive is on private property, it is the owner’s responsibility to arrange for it to be removed.
The European wasp is an introduced species that was first detected in Australia in 1959. Since then, it has spread to many parts of the country including Perth. The wasp enjoys the warmer Australian conditions and nests can grow to 3m in length and contain hundreds of thousands of wasps. Because they are attracted to cool drink and meat, they are a particular hazard around barbecues and also for pets. If swallowed, they can sting repeatedly (unlike a bee that can only sting once) and cause asphyxiation through swelling.
European wasps have been known to:
- Attack bees and bee hives, robbing the hives of honey and sometimes completely destroying them
- Damage soft fruits
- Cause environmental damage through direct predation on native insects
- Compete with other species including birds.
- They are also extremely aggressive, sting repeatedly with little or no provocation and if they do get established will seriously impact on our outdoor way of life by spoiling BBQs and alfresco dining.
The European wasp is about the same size and shape as a honey bee, but is not hairy.
European wasps have:
- Long, black antennae,
- The wings are folded when resting
- Legs are held close to their body when they fly
- Distinct bright yellow and black triangle-shaped markings on the body.
It is not to be confused with the Papernest wasp that is more slender and has an obvious waist section.
Wasp nests What to do if you see European Wasps?
The European wasp’s nest is always concealed. It is usually underground but can be located inside a hollow tree, a space in a retaining wall or embankment, in a wall cavity or the ceiling space of a house. The nest varies in shape depending on its location but can be very large. It consists of layers of cells and the outside is covered with flaky pieces of chewed up and cemented wood fibre.
The Papernest wasp’s nest, in contrast, is usually small (about the diameter of a 50-cent coin), fully or partially exposed, honeycombed in appearance and is often found on the underside of eaves or hanging off a branch.
Take precautions against European wasps by:
- Keeping food, drink or pet food inside
- Picking up fallen fruit
- Ensuring that your outdoor rubbish bins have tight-fitting lids
- Covering compost bins
- Covering food during a barbecue or picnic
- Drinking from a straw (don’t drink straight from a can or bottle when outside).
If you see a European Wasp leave it alone – it will only attack if provoked.
All suspected European Wasp sightings must be reported to the Agriculture Protection Board of WA on 9368 3472.
Please do not attempt to remove the nest yourself as this can be extremely dangerous.
Citrus Gall Wasp
The Citrus Gall Wasp is a pest of citrus trees in commercial orchards and home gardens. It arrived in WA in 2013 and is spreading rapidly; posing a significant threat to the citrus industry in WA.
To help minimise the spread of this wasp, you should:
- Check for galls from April to June.
- Prune-out galls by June 30 and place them in the sun to dry out (large galls should be chopped up).
- Galls removed after June 30 must be chopped up and solarised (in a plastic bag) in a sunny location for at least four weeks to kill developing larvae.
- Work with your neighbours to reduce reinfestation of your tree.
- Don’t move plants between properties, don’t leave galls on the tree or throw galls in the rubbish without treatment.
- Report citrus gall wasp using mypestguide.agric.wa.gov.au/reporter
More information on the Citrus Gall Wasp and its control is available at agric.wa.gov.au/citrus-gall-wasp or download the fact sheet.