Sick Bonsai??

[AussieBonsai]

Hi all. I’m new to bonsai and the forum, but excited to learn a new aspect of gardening.

I have bought my first bonsai, although it was very cheap and i now wonder if it is not suffering from fungus. I believe it is a Ficus, but concerned about the black trunk. The plant growth seems health though. Do I need to worry??

 

[AussieBonsai]

Actually I think it’s a water jasmine

 

[Shibui]

Black bark can be normal for some species but black bark can also be a sign of insect pests on the leaves. The insects suck on the sap and excrete sweet honeydew which then feeds a fungus which we call sooty mold.
Check the leaves and stems for tiny insects. Aphid and scale are 2 common pests that cause sooty mold. Aphid can be green, brown or black and move around, scales build a little protective lid and hide underneath so look for small brown lumps. Both those pests seem to love conditions inside a house.
They can be picked off with fingers but you are not likely to find every one so they just breed up again.
Methylated spirts wiped on with a cotton bud or cloth or even sprayed all over the tree should kill most adults but more will hatch from eggs so repeat after a week or 2.
Insecticides are also effective. You will need to look for something that kills the bug you find. Scale may need different to aphid. Oil based sprays are good for scale but need repeat treatment as more eggs hatch out.

It is a good idea the add a location in your profile so you will get suggestions for your area. Advice for cooler southern areas can be different to tropics.

 

[Forsoothe!]

Looks more like Fukien Tea. Possibly the worst starter tree in the world, but the deed is done. Check this out, and this one for a picture of scale use should be looking for.

Actually, pretty nice tree for a Chinese S.

 

[AussieBonsai]

That’s guys! It’s much appreciated. I’m pretty confident it’s aphid related, due to the sooty mold which was on some of the leaves. I’ve picked out any affected leaves, but have found no trace of actual aphids themselves. I’m in Singapore and so hibernation for these wouldn’t be an issue, I think. ?? The thing that’s got me confused is the state of the branches and trunk. I would have presumed that being so black and disfigured, would mean a very serious and long term infestation and yet the majority of the leaves look healthy, with no mold, etc.

 

[rodeolthr]

Is it possible that what we are seeing is perhaps just algae that has dried up since being removed from wherever it was grown?

 

[Forsoothe!]

Did you look for scale?

 

[AussieBonsai]

I’ve had a very close look for scale, and have found none, including carefully looking under any ‘casings’ on the trunk that they could be under. There is also no sign of honeydew, at least by the touch. I’e nothing sticky. Perhaps it is dried algae.

 

[Shibui]

The tree may have already been treated for whatever the problem was by the seller. Both sooty mold and old algae are very persistent even though they are dead. It often takes a couple of years for it to disappear as the older bark sheds.