How to treat Silver princess eucalyptus fungal infection?

[DanD1]

Hi everybody - Am looking for some assistance re a silver princess gum issue as our silver princess looks to have quite a bad infection, I'm guessing fungal? 

It is a mature tree about 5m tall, but the affected leaves are quite widespread and reach high up the tree to near the top. It has been dropping leaves quite a lot for a while.

Would be eternally grateful if anybody could recommend an appropriate treatment.

Thanks - Dan 

  

[MitchellMc]

Hi @DanD1,

Despite my efforts, I've not been able to pinpoint the cause of this discolouration. There are a few possibilities, but nothing I'm confident enough to call the reason. Let me mention our resident horticulturalist, @Noelle, to see if she has any thoughts.

Mitchell

[DanD1]

Thanks Mitchell 

[Noelle]

Hi @DanD1 

IMHO, I think it looks very like a fungal infection that is relatively common among eucalypts. I do not think it is myrtle rust as there does not appear to be any pustules present.  This disease is most often seen on the older leaves and is more prevalent when conditions have been humid - fungal diseases are always more common and widespread when humidity is high.

Spraying with a fungicide is not very practical especially on a taller tree. Allowing the soil to dry out a bit is often helpful as is raking up and removing fallen leaves, but generally the trees will survive without any specific treatment.

[DanD1]

Oh okay, thanks @Noelle  - It seems to be affecting the tree all the way to the top and looks quite bare so I'm worried it is dying. Is there anything else I can do to help the tree?

[Noelle]

@DanD1 , probably not much. Eucalypts that look like they are on the way out may often produce new shoots (epicormic growth) from the main branches and trunk, rather like trees damaged by fire will do. It is pretty much a waiting game unfortunately.

[DanD1]

Thanks @Noelle appreciate the help - Fingers crossed I guess 😬

[gamefisherman]

Get a systemic fungicide spray and give it a good spray. It may need two applications two weeks apart. Then give it two sprays of white oil over a fortnight. Pull any mulch back from the trunk so the ground around it can dry. Next sprinkle some anti fungal powder as well as spreading a slow release native fertiliser. Wash in with Seasol. Get the tree healthy again takes a bit of time but this will work. Keep branches from reaching the ground (ie cut them off before they hit the ground) and regularly rake around the canopy on the lawn to get rid of diseased or old leaves. If not resolved in a month after the above just repeat the above. You can also spray it with copper, or pyrethrum as an secondry response. Good luck, they are a stunning tree. Oh I forgot they don’t like wet feet so spray an anti rot tree root spray as well to protect the roots.

[DanD1]

Thanks @gamefisherman,  I will give that a go Did you have any recommendations for systemic fungicide and anti rot spray that are more favourable for princess gums?

[gamefisherman]

@DanD1 No worries mate. I’m no expert, just a person that likes to garden. Perhaps head to your local Bunnings and ask an expert re which ones to use. I always try to get a product that says it is suitable for use with Australian natives but this is not always the case due to limited product ranges for some sprays, fertilisers etc. All I did was a lot of Google searches to find what I needed as this is a problem that I couldn’t find much help with so I just did the dr Google thing over time. I think keep it as simple as possible however. Main thing is to get going with the sprays as we are coming into spring very soon and the new growth is already growing. I just don’t want to say buy brand x to you and it doesn’t work or worse. Just do your research re brands and go for it. Sorry I can’t be more specific re which ones to use but I’m confident that if you Google what you need you’ll find the answers. Good luck.