How to treat marks on Eucalyptus leaves?

[BenB]

Hi everyone,

I hope you're all doing well.

I have a question regarding our eucalyptus tree. Over the past 4-5 months, we've noticed some unusual marks on the leaves. Can anyone help identify what disease this might be and suggest how we can treat it?

Thank you.

Ben

[JacobZ]

Hi @BenB,

Thank you for your question and welcome to the Bunnings Workshop community, it is fantastic to have you with us.

I can't say I'm sure what the issue is. 

It's possible that it could be a fungal problem such as anthracnose, which can be treated with a copper-based fungicide such as Yates Liquid Copper Fungicide. 

It could also be related to watering. Have you had a lot of rain, or very little rain lately? Is the soil around the base of the tree dry or damp?

Did anything around your eucalyptus tree change in the last 4-5 months that may have caused stress to the tree? Did you change your watering habits? Did you notice any pests or insects that weren't there before?

You might like to read through How to diagnose a sick plant for some other tips.

Also, allow me to tag @Noelle, our resident horticultural expert to see if she has any thoughts.

Let me know if you have any other questions.

Jacob

[Noelle]

Hi @BenB 

It resembles water stress - either too much or too little - but it's a bit hard to diagnose with any certainty from just one image of a few affected leaves. What do the undersides of these leaves look like? Is it just on older leaves or are new leaves showing similar markings?

To be able to assist more, it would be good to know your location, soil type and what your weather has been like over the past 6 months.