Do you have bugs on your bonsai tree? There are many different types of bugs that you could find on a bonsai. Most of these are harmless or actually beneficial to the tree. However, we understand that you may not want bugs on their bonsai, so here are a couple of the most common bugs and how to get rid of them:
Aphids (blackfly, greenfly and whitefly) are sap sucking insects which rarely cause a problem for bonsai. As aphids are very easy to identify and easy to treat, so are no cause for alarm. They are more commonly spotted in spring/early summer.
Usually the first sign of aphids is shiny sticky patches on the top surface of the leaves. This is caused by honeydew which is excreted by the insects and drops from the leaves above (see photo 1).
Sometimes black sooty mould grows on the honeydew (see photo 2).
You can sometimes see white skin casts on the top of the leaves (they can look like a strange insects but are just empty aphid skins). (See photo 3).
You can usually see the aphids; they tend to colonise on the shoot tips (see photo 4).
We recommend that you spray weekly with a Plant Invigorator to prevent pests such as aphids developing.
Should you find that your do have aphid on your bonsai, please do not worry, simply purchase an insecticide from your local garden centre and follow the instructions. If you do not want to spray you can simply pick the insects off the shoots (keep checking that more do not hatch).
Scarid flies are not uncommon on seedlings and house plants. They are grey/brown flies which live in the soil surface and do no harm at all. Keeping the soil surface barely damp (and not wet) will discourage them. If you find them annoying simply spray with an insecticide. Occasionally you may spot a larvae, it is small, long white and slender. These flies are not something to be concerned about; they are rarely noticeable after a few days.
Update Summer 2020…
We have been aware of unprecedented levels of aphids (green fly and black fly) this summer which we have attributed to such a mild winter. Bonsai have been affected whether you have had it 2 weeks or 5 years and we are receiving a considerable number of emails from customers who have purchased from many nurseries in the UK so we thought we would write this email in an attempt to help you.
Aphids are everywhere this year. In gardens, on shrubs, roses, houseplants, in the air and occasionally regrettably in the buds of bonsai trees.
A few aphids will do no harm at all and can often be removed physically by picking them off the plant. Aphids can be identified as small green or back insects which sometimes leave a sticky residue on the leaves.
Preventing Bugs on Your Bonsai
On the nursery we actively spray weekly as a precautionary measure. We try not to spray intensively using nasty chemicals as we are aware of the environmental impact of this. Over the past few years insecticides have become less efficacious as the chemicals the companies use have become restricted. We treat all bonsai on a weekly basis, but the sprays are not long lasting. This is not a bad thing as we do not want to affect bees and other wildlife negatively.
Every bonsai we sell is checked prior to dispatch but we recommend that you continue with our regime of spraying occasionally with an insecticide. This is usually once a week or month to protect your bonsai.
If you find aphids on your bonsai tree, please remove them and spray once a week for three weeks with an insecticide. It is extremely important to spray under the leaves.
Then spray once a month as a preventative measure.
Additionally, please keep your bonsai somewhere bright but out of direct sunlight. This summer the weather has been extreme, at times incredibly hot so your bonsai may appreciate being moved somewhere a little cooler.
Keep the soil damp to the touch and not wet and mist the leaves daily with water to encourage back budding.
We hope that you find this information helpful.