Common Tree Diseases Found In South-East Queensland

Tree diseases are more common than thought across South-East Queensland. Our hot and humid client, paired with an abundance of tree species, make trees in our region more susceptible to a variety of diseases which can cause serious damage. Knowing what to look for when it comes to the most common tree diseases found in our region is crucial to being able to start treatment early and prevent the total destruction of the tree which means having it brought down in order to keep those around it safe.

Many of these diseases are caused by fungal pathogens, which thrive in the warm and humid climate. Other tree diseases, such as phytophthora, are caused by soil-borne pathogens and can be more prevalent in poorly drained soils. The first step when suspecting a tree might be infected is to call a professional arborist who can properly diagnose the problem and recommend the best course of action to take in order to preserve the tree if possible.

Here Are 5 Common Tree Diseases We Encounter

Powdery Mildew

This is a fungal disease that appears as a white powdery coating on the leaves and stems of trees. It can cause leaf yellowing, leaf drop, and reduced growth. Powdery mildew is more common in damp and humid conditions and it is characterised by a whitish powdery coating on the leaves, shoots and stems. The affected leaves may also turn yellow and drop prematurely.

common tree diseases - powdery mildew

Honey Fungus

This is a fungus that can cause the death of trees and shrubs. It is characterised by white, fan-like growths on the trunk and roots, and can also cause yellowing of leaves and leaf drop. Honey Fungus is a common problem in gardens and parks, it is identified by the presence of white fan-shaped brackets on the trunk and roots, which are actually the fruiting bodies of the fungus. The infected tree may also have yellowing leaves, and leaf drop.

common tree diseases - honey fungus


This is a group of fungal diseases that affects multiple species, including our well loved eucalyptus trees. It mostly affects the branches and leaves, with younger trees being more susceptible. You can spot Anthracnose by the appearance of small black, tan or brown lesions along the tree and distorted or curled branches. It is most prevalent in times where there is an excessive amount of moisture in the ground.

common tree diseases - Anthracnose


This is a soil-borne fungus that can infect the roots and lower stem of a wide range of trees and shrubs, causing wilting, dieback, and death. Phytophthora is more common in poorly drained soils, and it’s characterised by the sudden wilting of leaves, and dieback of branches.

common tree diseases - Phytophthora

Black Spot

This is a fungal disease that causes leaf spots, and can lead to defoliation of trees and shrubs. Black Spot is characterised by the presence of circular black spots on the leaves, which may be surrounded by a yellow halo. Black spot thrives in warm, humid climates which means it finds itself right at home in South-East Queensland.

common tree diseases - black spot

Always Engage A Professional Arborist Before Taking Action

It is important to consult with a local arborist to properly diagnose tree diseases. This is because tree diseases can be tricky to identify, and some tree diseases have similar symptoms, so it’s important to have an expert to properly identify the problem and recommend the most appropriate treatment. In addition, a professional arborist will have access to specialised equipment, and a deep understanding of the local environment which will help to diagnose and treat the tree disease correctly.

To arrange an on-side inspection of your trees by a trusted, qualified local arborist, get in touch with us at O’Brien’s Tree Care. Our team possesses a wealth of experience in diagnosing and treating common tree diseases and our invaluable advice can be the difference between the tree having to come down or live on. We can also provide advice on how to best care for your trees and their surroundings in order to reduce the risk of disease down the line. Talk to a qualified arborist by calling us on 0431 740 088 or click here to contact us online.