Is my Ulmus going to die?

2 weeks ago I bought a Ulmus Parvifolia. I live in The Netherlands and the ulmus is outside. Now it has small white flies on it, I sprayed it with Pokon Bio-Insect 2 days ago, but with no results yet. The leaves are turning yellow and start dropping off. I also noticed that when I water the ulmus, the soil is getting dry fast, the soil isn't retaining water. What should I do?

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TreeBay

Hello Ike, the soil should drain freely, but if it isn't holding any moisture there may be a problem. You want the soil to almost - but not quite- dry between waterings.

It might take your spray a couple of weeks to work. Some of them do not affect the adult insects.

Do your pests look anything like the whiteflies at this website?

http://whiteflies.ifas.ufl.edu/wfly0002.htm?

Regards,

Matt

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Hi Matt,
Thanks for your reply. It looks a lot like the silverleaf whitefly.
Should I keep spraying?
The soil is drying up rapidly, after watering, is repotting an option?

Thanks,
Ike

TreeBay

It's confusing as to why the soil would dry so much when there aren't healthy leaves.

You might want to up-pot it into a larger container... if it is in one of those very small "mallsai" pots. They are look like ceramic or plastic 4" liners, because they are.

Another thing you could look at adding is a humidity tray (some over at ***CHARLEY***) or giving it just a bit of afternoon shade if you are in a dry or windy area.

Regards,

Matt

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Thanks. If I put it in another pot, do I remove all the soil from the roots and change it with bonsai soil?

Regards,
Ike

Tony

ike, have a look at the roots. It's possible that it's so root bound that the water isn't penetrating and most of the roots are staying dry. If not that then you may need more organics in your soil and more shade in the afternoons.

It has small black spots on the leafs now, any idea what that is?

Tony

Believe it or not there is a fungal disease called "black spot" that elms and zelkova are especially prone to get. Try taking a leaf to a nursery man and see if they can Id. it. We use captan and daconil to treat it over here. I'm not sure of what brands are available in the Netherlands.

Tony