AusBonsai

HI,

I recently bought this Silver Birch bonsai starter.

When I bought it there were a few tiny holes in some of the leaves, but I took a chance and bought it anyway.

Since I have got it home the holes have got much worse. The leaves are also turning browning around the edges, but I guess that is just the start of autumn colour (I may be wrong).

It's potted in some well draining soil and is watered once a day.

I haven't seen any bugs or ants on it.

Does anyone know what might be causing this?

I wouldn't be too worried.
This late in the season I'd say they will drop soon.
From what I can see the tree looks healthy enough to get through to next spring.

My understanding is that holes will be directly related to an insect of some form.
Therfore an insecticide would be the option to try if you're really bothered.

Your leaf damage is definitely from something eating the leaves. From the size of the holes I'd guess that it is quite small so maybe you have missed it when searching. Many insects are well camouflaged so could be quite hard to spot or it might be hiding in the soil and only coming out to feed at night.
Boics is right that trees cope well with small amounts of leaf damage and the leaves will soon fall anyway.

That's reassuring.

I will just leave it for now and hope it does come back in spring (whatever it is).

Thanks for the advice.