Pests

A major nuisance ant in Western Australia is the coastal brown ant which are often found in lawns and brick paving. Control procedures for a particular ant species may not be effective for other ant species so it is recommended that pest ants are identified before attempting to control them. The Department of Agriculture offers a free identification service. To access the service, visit the Coastal brown ants, big-headed ants | Agriculture and Food.

European wasps are declared pests in Western Australia and must be eradicated when found. The Department of Agriculture and Food provide a fact sheet for identifying European Wasps. If you suspect you have seen European wasps, please report the sighting using the Department of Agriculture and Food  MyPestGuide or contact the Pest and Disease Information Service (PaDIS).

For information on removing beehives please refer to the WA Apiarists Society.

Midges belonging to the insect family – Chironomidae, are small non-biting insects that live and breed naturally in Perth’s lakes and wetlands and are an important part of the ecosystem. They are not vectors of disease, however, in large numbers, adult midge swarms can cause a nuisance to nearby residents.

Midge monitoring

The following efforts are made to monitor midge:

• The Cities of Joondalup (CoJ) and Wanneroo (CoW), in conjunction with the Department of Environment and Conservation (DEC), conduct regular monitoring and identification of midge larvae within Lake Joondalup and Lake Goollelal.
• Nuisance adult midge swarms are monitored during periods of high-level midge breeding to assess the impact on nearby residential areas.
• Records are kept of customer enquiries/concerns in relation to the impact of nuisance midge swarms.

Midge control

Chemical spraying of lakes and wetlands is a short-term control measure which can be carried out during periods where midge larvae counts are high and there is an increased impact of nuisance adult midges on nearby residents. The frequency of these treatments is limited by environmental restrictions and is dependent on the availability of approved chemicals.

Ongoing management

The Cities of Joondalup (CoJ) and Wanneroo (CoW), in conjunction with the Department of Environment and Conservation (DEC), are involved in the following midge management strategies:

• Provision of funding for, and management of, research projects which investigate factors affecting water quality and elevated midge breeding. These studies provide valuable information for the creation and implementation of midge management and reduction initiatives.
• Continued re-establishment of fringe vegetation surrounding wetlands to reduce nutrients entering the water bodies and to provide barriers between the wetland and residential areas.

Reducing the impact of midge

To reduce the impact of nuisance midges around the home, residents living near lakes and wetlands should consider:

• Use yellow, low wattage globes (25 Watt or 30 Watt) around the home and reduce lighting to external areas
• Installing fine mesh screens over your windows to prevent midges from accessing your home by sealing gaps around doors, windows and skylights
• Plant local native plants in your garden which screen lighting from your property • Reduce run-off of nutrients into the environment by: 
  • Disposing of household waste appropriately, not down stormwater drains • Washing cars on the lawn rather than the driveway or street
  • Using nutrient free detergents
  • Using slow-release fertilisers on lawns and gardens.
  • Where properties have been provided with sewer, but are still using septic tanks, decommissioning these septic tanks and effluent disposal systems and connecting the property to the Water Corporation sewer.

As well as being a nuisance, some species of mosquito carry viruses such as Ross River Virus and Barman Forest Virus. For simple preventative measures that you can take to protect yourself from mosquito bites, and to help reduce mosquito numbers, please refer to the prevent mosquito bites page on the Healthy WA website.

For more information about Polyphagous shot-hole borer, please refer to the Tree maintenance and removal page.

Rats and mice are almost always present throughout suburban areas due to the opportunities for food and shelter provided as a result of human activity.

In established suburbs, food and water is readily available from such places as drainage and irrigation systems, vines, fruit trees, palm trees and pet food. Rodent numbers, like those of many wild animals, fluctuate according to several factors, but rats will always be present, to some degree.

Rats are considered a nuisance because of the damage they can do to buildings as well as the odours created by their colonies.

Signs of rats

The following signs indicate the possible presence of rats:

• Droppings - these are oblong and between 12mm to 20mm in length. When found in cupboards, window ledges, alongside skirting boards or in sheds, this is usually the first sign of a rat infestation. Shiny, dark, pliable droppings are an indication of recent rodent activity
• Remains of snail shells with the insides eaten out, nutshells, bones, seeds and other debris in the corner of sheds and other private spots
• Greasy rub marks on vertical surfaces from continual contact with rodent fur
• Signs that fruit and vegetables from gardens have been eaten
• Gnawing damage in a wide range of materials including wood, soft metals, soap, food containers, conduit and cables
• Squeaking, gnawing or movement sounds in walls, cupboards, ceilings and under floorboards
• Pets becoming more excitable than usual
• Footprints and tail marks on the ground or along dusty surfaces
• Nests hidden in buildings made from rags, paper, cardboard, straw and other materials.

Preventing rat problems

The presence and number of rats is determined by the availability of food, water and shelter. By denying the rodents these lifelines, you can effectively control rat populations. You can do this by:

• Stacking wood above the ground (about 40cm ) and away from sides of sheds and fences
• Removing fruit and nuts from vines and trees at the end of the season and picking up rotten fruit from the ground
• Removing fruit from palm trees when in season
• Keeping the backyard as clean and free of debris as possible
• Maintaining rubbish and compost bins in good repair, free from holes and with secure lids
• Keeping pet dishes clean and storing bulk pet food in closed containers
• Regularly removing garden waste and rubbish from sheds and around the yard
• Regularly cutting back tree branches and palm fronds to prevent easy access to the gutters and roof
• Blocking holes and other potential access points around all buildings
• Upturning unused containers exposed to the weather so they do not collect rainwater.

Rodent control methods

The two most common ways of controlling a rat problem:

Baiting

Involves laying poison baits along known rodent trails and in roof and wall cavities that are easily accessible. Many brands of bait are available at supermarkets and hardware stores. Ensure to read the packet instructions carefully and once laid, check the baits regularly to see if rats have been eating them.

Some rat baits may present a risk to native wildlife through the unintended consequence of secondary poisoning, which might occur when native wildlife feed on rats or mice that have eaten rat bait. To reduce the risk of secondary poisoning, ‘Second Generation Anticoagulant Rodenticides’ (SGARs) should be avoided. SGARs often contain ingredients such as rodifacoum and bromadiolone.

When placing the rat bait in the roof cavity, place the bait within sight of the access hole so the baits can easily be checked. It is very important to place baits where small children or pets cannot reach them.

A starter pack of the recommended rat bait may be collected by City of Joondalup residents from the Customer Care Centre: City of Joondalup Administration Building 90 Boas Avenue Joondalup WA 6027. Please note: there is a limit of one pack per household, per year.

Trapping

Trapping is the next most common way of ridding any property of rats. There are two different types of traps - snap-back trap and a plastic capture box.

Different types of bait can be used, including bacon rind, chocolate, fish, nuts, prunes, apples or peanut butter.

Rats are sometimes suspicious of new objects or surroundings so they may stay clear of the trap until it becomes familiar.

Placing the trap in the path of a rat and hiding the trigger under straw or cardboard is one way to get around this trap shyness.

Please ensure to avoid contamination of food by animal urine, droppings or blood by placing traps away from (and never above) food or food preparation surfaces.