Aphids And Bonsai, What Are They And How To Treat Them

How To Get Rid Of Aphids On Bonsai

Before we defeat our enemy we must first understand our enemy, After all any pest that try's to attack your bonsai are the enemy.

What Are Aphids?

Aphids are tiny little sap sucking pests, No I'm not calling them names that's what they actually are. Aphids congregate in masses on your trees and suck the sweet sap from your tree, Female aphids can also reproduce without a mate so they can multiple rapidly over a single season, any infestation left unchecked can cause some serious weakening of your trees. Aphids can come in all sorts of colours from brown, black, yellow and green. They are very small so it takes some careful investigation of your trees to see an infestation, but there are some tell tale signs which we will talk about now.

How To Identify An Aphid Infestation

After aphids have eaten the sap from the tree they then produce a sweet sticky excretion called "Honey Dew", Often times you can see this honey dew on your benches as it drips from the aphids off the branches. You will know its honey due as it will be very thick in texture and very sticky, it will appear randomly around your pot and may even be running down the sides of your pot. Another dead give away is ants! ants will actually protect the aphids, in return the aphids will allow the ants to feed on the sweet honey dew. So if you see a tree that has ants all over it then there's a good chance you might have aphids.

Another sign that you have aphids maybe be sooty mould, the honey dew they excrete can cause these black spots to appear on your leaves, This isn't always caused by aphids but it can be a sign.

How To Prevent Aphids On Bonsai

You've probably heard this before but the best way to prevent any kind of pest on your bonsai is to have a healthy tree. Make sure you have been fertilising well and that your fertiliser has a good amount of potassium in it. The stronger your tree is the more natural defence it has against pests. i have also found that the years i haven't done a winter spray of lime sulphur i have been more prone to aphid infestations at the end of winter / early spring. Don't spray your Australian natives with lime sulphur though, it will cause the entire tree to drop its leaves. Natives aren't very prone to aphid infestations any way, They have their own enemy's. The rest of your trees may benefit from a beginning of winter and mid winter spray of lime sulphur though which will combat both pests and fungal infections which are more prominent during winter. 

How to Treat Aphids On Bonsai

There are a few ways to go about this, 1 simple way is to blast them out of your tree with the hose. Aphids generally don't hang on very tight so a nice solid stream of water evicts them from your tree pretty quickly, this is a nice easy free way to go about it but it does come with some down sides. When blasting your tree with a stream of water that's strong enough that it can remove the aphids might also do some damage to your tree or wash away your soils surface, This also doesn't get rid of the aphids permanently and they may just move into another tree near by.

Another method is using a pest oil, Pest oils are a contact spray and is applied directly to the aphids, Pest oils will clog the pores they use to breath and suffocate them so it is a very effective treatment, but once again there are some downsides. When using oil you need to be carful of the species, junipers and pines for example should never have any kind of pest oil applied as it will clog their pores which could be very bad for the tree. Pest oils in mid summer can also cause some leaf burn if left to sit in direct sunlight. 

The next method is using Imidacloprid which we sell in the form of Congaurd. This can be mixed up as a spray and used with a Pest And Disease Spray Bottle. Congaurd is a contact spray that will kill the aphids with no negative effects. It can be used on a wide range of species and will treat the aphid infestation fast, Make sure you apply the spray on a day that hasn't got a high chance of rain as you will want the spray to work before it gets washed away. When applying any kind of treatment always take precautions, wear safety goggles to prevent getting spray in your eyes if the wind blows ( trust me its a problem) lay newspaper over your soil surface so you can give your foliage a good drench without too much entering your root ball ( although congaurd is systemic i still take this precaution ).

I hope this has helped you understand aphids on bonsai a little better and has given you some ideas on how to identify, prevent or treat aphids.

Until Next Time, Enjoy Your Bonsai Journey.