AusBonsai

Hey guys,

I'm having a bit of a problem with some bugs eating my Chinese Elm leaves. Any help or advice with this would be great

When i inspect my elm i can't find anything like a caterpillar or something large so i'm a bit lost to what is munching down on my elm. and how to kick it in the butt.

As i know everyone loves pictures here are 4 to hopefully shed some light on my little problem.


close up of leaves 1


close up of leaves 2



Fresh leaves are all but gone on some newer branches. Big thanks to the hand model

At the moment i'm giving it a light spray with a pest killer i got from bunnings but haven't done it for a while because i hadn't notice the leaves being munched on. Gave it a spray this morning though after taking the photos.
Also the wife is going out on saturday so i'm going to fill up the bath and give the elm a good soak to drown anything in the soil that might be coming up for a feed on the leaves.
I have 3 figs right near my elms and they are not effected in the slightest so its isolated to my chinese elms.

Any help or advice on this would be great.

Thanks in advance

I am no expert on this but my understanding is that insects eat from the outside of the leaf in and when damage crosses over veins as you show then it is a fungus or something similar.
Bugs are meant to eat from the outside in avoiding the tough vein of the leaf.

Will be interesting what the more experienced have to say?

Bretts wrote:I am no expert on this but my understanding is that insects eat from the outside of the leaf in and when damage crosses over veins as you show then it is a fungus or something similar.
Bugs are meant to eat from the outside in avoiding the tough vein of the leaf.

Will be interesting what the more experienced have to say?

A fungal problem? I doubt it.

Hi Ware-bonsai.
No, it's not true that insects only nibble at the leaf margins. Many, many insects skeletonise leaves, my advice is that your problem is not very widespread and that there are no obvious masses of bugs on your tree when you search for them, so treatment is probably not necessary at the moment. Chinese Elms are pretty robust and can stand having a few nibbles taken out of them. It is probably the odd catterpillar, slug, grasshopper that is passing by and stopping for a feed. Keep an eye on the tree, just to be on the safe side, but don't be too concerned at present.

Cheers,
Mojo

The damage looks very much like elm leaf beetle. Both larvae and adults eat leaves. Here they rarely eat Chinese elm but love English elm and zelkova so maybe it is something else on your trees. Adults are small - about 4-5mm long but drop to the ground if disturbed so you often don't see them. Grubs are small and black and pupate in cracks in the bark or in the ground. A good insecticide should get rid of them but they will keep coming back from trees nearby.

Try wrapping sticky tape around the trunk of your elm,not to wide, sticky side out, so if anything is crawlling up the trunk to get to the leaves, you will catch them.

Mud

Mudeye - do you think you're tape trick will work on my chocolate that seems to go missing in my fridge ??

Matt - looks like some of my elms, I've too not seen any grubs or bugs on my plants but that's what I reckon they are.

They're tough trees, I wouldn't stress too much.
And I figure they're going to lose they're leaves soon anyway.

Tex

Tex
For the chocolate bug try industrial gaffa tape..

Mud

hi tex the easiest way to catch a chocolate thietf is to swap the chocalate with laxative blocks
but to the post i got chinese elm and if i find leaves with a problem i just pick them off
cheers dean the terror

Moj has hit it on the head. Definitely Elm leaf beetle. They will not kill your tree, just make it look unsightly. As y0ur tree gets better and you learn to defoliate, leave the bucket with the defoliated leaves in it next to the tree. The beetles go back to the leaves and you move them out of town the next day.

bodhidharma wrote:Moj has hit it on the head. Definitely Elm leaf beetle. They will not kill your tree, just make it look unsightly. As y0ur tree gets better and you learn to defoliate, leave the bucket with the defoliated leaves in it next to the tree. The beetles go back to the leaves and you move them out of town the next day.

Hi Bodhi, great non-chemical treatment for ELB, I'll have to try it. It was Shibui that actually diagnosed it correctly, I had a hunch it might be them. That is barely a nibble compared to what Elm Leaf Beetle can do to English Elms as you would know.

Cheers,
Mojo

Hi guys,

Thanks for all the feedback. Helps a lot to put my mind at ease.

bodhidharma - you mentioned that it would be good to defoliate the elm to get them away from the tree. Can you give me some advice on when is the best time to defoliate a chinese elm? I figure now isn't ideal because it is coming into winter and it will already loose leaves during the colder months.

tex - I think your chocolate problem is a little wide spread for just some tape. Maybe a human sized mouse trap contraption is in order haha to keep your little one and wife at bay Looking forward to our next bonsai meet though next month as i think i'm going to bring over this elm to show you the progress. Or maybe my trident maple who knows.

Thanks again for all your advice guys. I think every 3-4 days i'm going to give my elms a light spray with some insecticide just to give the little suckers something to think about