AusBonsai

Hi all,

I've had a few trees develop this orangey, clumpy mass over time. It looks like perhaps some kind of fungus or something.

I'm tempted to think it's from over-watering, because I noticed that it developed around the same time some algae, I recently treated, did (which was believed to be from over-watering too).

Does anyone have any idea what it is; whether it's harmful, and; how to get rid of it?

Thanks

Hi,
I don't know exactly what it is but have a couple of questions -
1) Does it come back if you scrape it off?
2) When was the last time you repotted? Maybe you could check the root mass for mycelium (fungal growth) in the soil around the tree..
I hope it isn't something harmful
Best of luck

Sorry just re-thought that second part, if it is growing directly on the bark it is most probably living off the wood in the tree and then would not have much hyphae under the soil.

it looks a bit like rust fungi to me. rust is generally on the leaves but i dont see why it couldnt possibly be on the bark too!

Hi all,

Thanks for helping with this

Bonscythe: It does come off when you scrap it - well most of it anyway! I re-potted it late last year around September, and haven't really altered the soil in any way since.

Rust fungus, eh? Hmmm... I'll research some more about it- thanks for the lead. I'll try and get some clearer photos soon so you can see it a little better.

Thanks again

I highly doubt it is rust as rust tends to go for leaves instead. It looks to me like Bryobia Mite. I had it on my Chinese Elm once. The young mites which are usually red come out at night and feed on the leaves (Have you had any leaf damage of any kind)?? They love branch junctions and bark crevices. This species of mite does not produce webbing. They can be eradicated using wettable sulphur, white oil or difocol. You may need a few applications.

I highly doubt it is rust as rust tends to go for leaves instead. It looks to me like Bryobia Mite. I had it on my Chinese Elm once. The young mites which are usually red come out at night and feed on the leaves (Have you had any leaf damage of any kind)?? They love branch junctions and bark crevices. This species of mite does not produce webbing. They can be eradicated using wettable sulphur, white oil or difocol. You may need a few applications.

Thanks Jester. I've not had any leaf damage so far on the tree that the photo is of, but I have two with similar markings that do (though they were knocked to the floor recently, and I wonder if the shock may have created the recent leaf damage).

My trees have had problems with mites in the past though, and I do have some pyrethrum which hasn't hurt any of my trees in previous applications. Should I perhaps give them a light spray?

Hi Emoska, I'll be honest, I have not used Pyrethrum myself so I am in no position to advise on this chemical. However, since my last post , I would like to add that if I were you I would actually consider giving the "Yates Mite and Insect Killer - Natrasoap Gun" a try. I've had good results with this and it is not as toxic as the others I mentioned. Hope this helps.