Garden pests can damage leaves, stems, flowers, fruit and young plants. However, not every insect or mite found in a garden requires treatment. Ladybirds, lacewings, predatory mites, native bees and parasitic wasps can help pollinate plants or control harmful species naturally.
Before using a pesticide, identify the organism and confirm that it is causing unacceptable damage. An integrated pest management approach combines monitoring, garden maintenance, physical removal, biological controls and, where necessary, targeted pesticide use.
NSW Department of Primary Industries describes integrated pest management as using multiple control methods while prioritising the least ecologically disruptive options. dpi.nsw.gov.au
Identify the Garden Pest First
Inspect the affected plant carefully before deciding on treatment. Check:
- The upper and lower surfaces of leaves
- Stems, buds and new growth
- Damaged fruit and vegetables
- Soil around the base of the plant
- Nearby weeds and fallen plant material
- The garden at night, when slugs and snails are more active
Take clear photographs of the pest and damage. If identification remains uncertain, ask a nursery horticulturist, agronomist, NSW plant-health service or other suitably qualified professional.
Plant damage can also result from disease, poor drainage, nutrient problems, heat, frost or incorrect watering. Finding an insect on a damaged plant does not prove that it caused the problem.
Common Garden Pests
The pests affecting a Newcastle garden depend on the plants, season and surrounding environment. Common examples include the following.
Aphids
Aphids are small, sap-feeding insects that often gather on new shoots, buds and the undersides of leaves. Heavy populations may cause curled growth, yellowing, reduced vigour or sticky honeydew that encourages sooty mould.
However, small aphid populations may be controlled naturally by ladybirds, lacewings and parasitic wasps. NSW guidance identifies these beneficial insects as natural pest controllers that can reduce reliance on pesticides. dpi.nsw.gov.au
Beetles
Australia has more than 30,000 described beetle species, but they do not all damage gardens. Many beetles are harmless or beneficial. Ladybirds may feed on aphids, while dung beetles help break down animal waste. Australian Museum
Treat beetles only after identifying the species and confirming that they are damaging the plant. Leaf damage alone may not reveal which organism is responsible.
Caterpillars
Caterpillars are the immature stages of moths and butterflies. Some species feed heavily on vegetables, seedlings, fruit or ornamental plants. Examples include cabbage white butterfly larvae, cabbage moth larvae and cutworms.
Not every caterpillar needs to be removed. Some become native pollinators, and low numbers may cause little meaningful damage. Look for active feeding, droppings and repeated damage before deciding on control.
Mites
Plant-feeding mites are arachnids rather than insects. Many are extremely small and may be difficult to see without magnification.
Spider mites can cause pale stippling, bronzing, distorted growth and fine webbing. However, some mites are beneficial predators that feed on plant pests. Accurate identification is important because broad-spectrum pesticide use may kill predatory mites and allow pest populations to increase.
Integrated programs combine monitoring, biological controls and selective chemical treatment where necessary.
Slugs and Snails
Slugs and snails commonly feed on seedlings, soft leaves, fruit and other tender plant material. Damage often appears as irregular holes accompanied by silvery trails.
They prefer moist, sheltered conditions and usually feed at night. Reduce hiding places by removing unnecessary boards, pots and dense debris. Avoid excessive evening watering where practical.
How to Control Garden Pests
Monitor Plants Regularly
Check plants at least weekly during periods of active growth. Early detection makes physical removal and other low-impact controls more practical.
Do not treat plants simply because one insect is present. Consider whether damage is increasing and whether natural predators are already controlling the population.
Improve Garden Hygiene
Remove badly affected plant material, fallen or rotting fruit and unnecessary weeds that may harbour pests. Dispose of infested material carefully rather than moving it to another part of the garden.
Clean tools after working with affected plants, particularly if disease may also be present.
Use Physical Controls
Depending on the identified pest, physical controls may include:
- Hand-picking larger caterpillars, beetles, slugs and snails
- Pruning heavily infested shoots
- Using fine insect netting over suitable crops
- Applying horticultural barriers around vulnerable seedlings
- Washing small aphid populations from sturdy plants with water
- Using traps designed for the identified pest
Wear gloves when handling insects, slugs or snails. Do not collect unidentified insects indiscriminately because they may be harmless or beneficial.
Avoid spreading salt through garden beds to kill slugs and snails because it can damage plants and soil.
Protect Beneficial Insects
Broad-spectrum insecticides can kill pollinators and natural predators as well as the target pest. Predatory ladybirds, lacewings, mites and parasitic wasps can provide valuable natural control.
Where chemical treatment is necessary, select a product registered for the identified pest and plant. Follow its label regarding application rate, harvest intervals, protective equipment and environmental precautions.
Use Pesticides Only as Directed
In NSW, pesticide users must follow the approved product label. Incorrect application can harm people, pets, wildlife, beneficial insects, plants and waterways.
Before applying a garden pesticide:
- Confirm that the product lists the target pest and plant.
- Read the complete label.
- Measure the product accurately.
- Avoid spraying during windy weather.
- Protect ponds, drains and waterways.
- Keep children and pets away as directed.
- Follow withholding periods for edible crops.
- Avoid spraying open flowers or active pollinators unless the label permits it.
- Store and dispose of the product as instructed.
Natural or homemade products are not automatically safer. Some can burn foliage, harm beneficial organisms or create unnecessary exposure.
For broader pesticide and prevention guidance, read our effective pest control tips.
When to Request Professional Advice
Consider professional advice when:
- You cannot identify the pest.
- Damage continues despite garden maintenance.
- Several plants are affected.
- The pest is inside or damaging the building.
- You suspect an invasive or reportable plant pest.
- Treatment requires specialised equipment.
- You are unsure which products are legally suitable.
Newcastle Pest Exterminators primarily provides structural pest management for homes and businesses. Before publishing a claim that the company treats aphids, caterpillars, plant mites, beetles, slugs or snails, confirm that these horticultural services are currently offered and covered by the technicians’ licences and insurance.
If the problem involves household pests entering from the garden, explore our pest control services or contact the team to ask whether the issue falls within its service scope.
