Tree Pests and Diseases in Perth WA: How to Identify and Treat Them

Termite mounds

Trees are a vital part of Perth’s natural landscape, providing shade, improving air quality, and enhancing the beauty of properties.

However, tree pests and tree disease can threaten their health, leading to significant damage or even tree loss.

Knowing how to identify and treat these issues is essential for maintaining a healthy garden or property.

In this guide, we’ll explore common tree pests and diseases in Perth WA, their symptoms, and the best solutions.

Common Tree Pests and Diseases in Perth WA and How to Treat Them

1. Termites in Trees

Signs: Hollow trunks, weakened branches, and mud tubes on the bark.

Treatment: Yes, you can treat a termite infestation in trees, but success depends on how advanced the infestation is.

Some termite species, like Coptotermes acinaciformis, are highly destructive and may require professional treatment.

How to Treat a Tree Termite Infestation in Perth

1. Identify the Termite Species

• Subterranean termites (Coptotermes, Mastotermes) – The most destructive; they build mud tubes and attack both trees and buildings.

• Dampwood termites (Porotermes, Stolotermes) – Usually found in dead or rotting trees.

• Arboreal termites (Nasutitermes) – Less damaging; build mud nests in trees.

2. Treatment Methods

• Destroy the Nest

• Use Bait Stations

• Remove Infected Wood

• Improve Tree Health

• Reduce moisture 

• Encourage natural predators 

  
  

When to Call a Professional in Perth?

• If the infestation is large or near buildings

• If you see mud tunnels leading from the tree to your home

• If DIY treatments don’t work after a few weeks

There are many professional tree surgeons in Perth WA who will be able to inspect your affected tree and advise on whether it would be best to treat it or whether a tree removal service would be the most effective approach.

A towering termite mound stands amidst the arid Australian landscape

2. Aphids on Trees

Signs: Sticky leaves, black sooty mould, and stunted growth.

Aphids thrive in Perth’s warm climate, especially during spring and summer. You may also notice ants crawling up and down the trunk, as they are attracted to the honeydew aphids produce.

Aphid on a leaf

If left untreated, aphids can weaken trees, making them more susceptible to drought stress and disease.

Treatment: Natural remedies like neem oil can work well to control aphids without harming beneficial insects.

In Perth gardens, a strong spray of water can also dislodge aphids from the leaves.

Regularly pruning affected areas and maintaining healthy soil can further reduce the risk of infestations.

Researching tree pests specific to Perth’s climate is crucial. Some tree species, like citrus and ornamental trees, are particularly vulnerable to aphids.

Understanding the best organic solutions suited for WA’s conditions—such as drought-resistant companion planting or eco-friendly sprays—can make pest management easier.

Avoid chemical pesticides that can harm native wildlife and beneficial insects like bees.

With the right knowledge and preventative measures, you can keep your trees healthy and aphid-free all year round.

3. Borers in Trees

Signs: Small holes in the bark, sawdust-like frass, and branch dieback.

Treatment: Prune infested branches and apply a systemic insecticide if necessary.

How to get rid of pests in trees naturally? Maintaining tree health is the best defense against borers. Healthy trees can resist infestations more effectively.

Regular watering (especially during Perth’s dry summers), mulching, and using organic fertilizers can strengthen trees and make them less vulnerable.

Removing dead wood and avoiding unnecessary wounds to the bark also help prevent borers from gaining access.

If you have native trees like jarrah or marri, be extra vigilant, as they can attract specific borer species in WA’s climate.

4. Scale Insects on Trees

Signs: Bumps on twigs, yellowing leaves, and honeydew secretion leading to mold growth.

Treatment: Horticultural oil or insecticidal soap works well against scale infestations.

5. Root Rot in Trees

Signs: Wilting, yellowing leaves, and soft, decayed roots.

Treatment: Improve drainage and avoid overwatering.

In severe cases of root rot, professional tree removalists have much experience in providing efficient and cost effective tree removal services.

6. Powdery Mildew on Trees

Signs: White, powdery fungal growth on leaves.

Treatment: Prune affected areas and use fungicides.

DIY tree pest control that works includes increasing airflow around trees.

7. Canker Disease in Trees, Perth WA

Signs: Canker disease presents as sunken, cracked lesions on the bark, often oozing sap.

Over time, the affected branches may wither and die, especially during hot summers.

Some native species, such as eucalypts and banksias, are particularly vulnerable.

Causes in Perth’s Climate:

• Hot, dry summers can stress trees, making them more susceptible.

• Wounds from pruning or storm damage provide an entry point for fungal and bacterial infections.

• Common pathogens in WA include Botryosphaeria (which thrives in dry conditions) and Phytophthora (which affects moisture-retaining soils).

  
  

Treatment & Management:

• Pruning: Remove affected areas in dry weather to prevent further infection, and sterilize pruning tools between cuts.

  
  

• Fungicides: Use copper-based fungicides if bacterial canker is suspected, but chemical treatments are often less effective in advanced cases.

  
  

• Watering & Mulching: Perth’s sandy soils drain quickly—deep, infrequent watering and organic mulch can reduce stress.

  
  

• Avoid Wounds: Minimize pruning in summer when trees are already stressed, and protect trunks from mechanical damage.

  
  

• Choose Resistant Species: If planting new trees, select drought-hardy, disease-resistant species suited to Perth’s climate.

How to Prevent Tree Pests and Diseases in Perth

• Proper Tree Care Practices: Regular pruning, watering, and fertilization keep trees healthy.

• Routine Inspections: Identifying issues early prevents severe damage.

• Tree Pest Prevention Tips: Use mulch and organic sprays to deter insects.

• Expert Assistance: Consult tree health management services to detect and prevent pest and disease problems before they escalate.

  
  

Protecting your trees from pests and diseases ensures they remain healthy and strong for years to come.