Bonsai Pest Damage How to Eliminate Their Dangerous Attacks

  • By: Josh Koop
  • Date: August 24, 2021
  • Time to read: 11 min.
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Even if you have been diligently taking care of your bonsai trees, pesky bugs will find a way to infest them. Insects are one of the most common causes of the early death of bonsai trees. That is why you have to be prompt in getting rid of them as soon as possible. So, how to get rid of bugs on bonsai tree? 

You can get rid of bugs like aphids, whiteflies and spider mites from your bonsai trees using home-made insecticidal soap mixture or neem oil mixed with water. Other ways you can get rid of bugs is by taking the help of parasitic wasps or by baking the soil. 

Different bugs require different removal methods. That is why there is so much more you need to know and understand to properly take care of your bonsai tree. Hence, I highly suggest you read on. 

Why Does My Bonsai Tree Have Bugs?

There are many reasons why bugs are eating your bonsai tree.  Overwatering your bonsai tree can cause infestations. Or the soil you bought may have come infested with bugs to begin with. 

If you overwater your bonsai trees, there is a chance fungus gnat might attack your tree. Because fungus gnats grow on moist and humid soil. 

Then again, pests like fungus gnats sometimes even come in with new soil bags from the suppliers. You only notice the soil was to blame when the bug colonies expand.

Pests and bugs can also infest your bonsai tree during soil changes. Again, if you introduce a new bonsai plant in your planter, bugs can infest both the trees and the soil. 

In warm humid weather your bonsai trees may get attacked by mealy bugs. There is also a chance that your bonsai tree came infested with tiny bugs when you brought it and you only noticed after the bugs multiplied.

Infestation of Aphids
Infestation of Aphids

How to Get Rid of Bugs On A Bonsai Tree?

Different types of bugs require different treatments. But there are some common one that every bonsai owner faces at least once in their lifetime. These include aphids, white flies, fungus gnats, spider mites and mealybugs. I will be going through how to get rid of each of them below – 

Aphids

You can remove aphids on your bonsai without using any strong insecticides. You can get rid of the aphids naturally using insecticidal soap water, neem oil, lacewing larvae or ladybugs. If you want any generic store-bought pesticide, you can purchase plant pins.  

All you need to get rid of aphids on your bonsai tree is three cups of water, a tablespoon of dish detergent and a spray bottle. Spray the mixture on the affected area and wait for 8 to 10 minutes for the aphids to die. 

Neem oil is not only an organic insecticide but also takes the removal of aphids another step further. It also stops the production of eggs in bonsai trees.

All you have to do is mix a few drops of neem oil with water and apply it on affected areas of the bonsai tree with cotton swabs. You can find neem oil in 70% concentration as miticide and fungicide in stores

Do not use neem oil before sunset. It can react to the sunlight and overheat the bonsai tree. Whether you use soapy water or neem oil, make sure to wipe away the excess neem oil or soapy water along with dead aphids with a paper napkin or sponge. 

Again, before spraying the mixture all over the bonsai tree, spray it on a leaf and observe if the mixture harms the plant. If the mixture is too strong, you should adjust it by adding more or less soap or neem oil. 

You can attract other insects like lacewing larvae and ladybugs to do your job. Lacewing larvae are called “aphid lions” because only one of them can devour over 300 aphids. 

Again, you can release ladybugs inside your miniature greenhouse. If you have enough food prepared for the ladybugs, they will eat up all the aphids without harming your bonsai tree.

It is hard to identify whether the aphids attacked your bonsai roots or not. What you can do is while repotting your bonsai tree, you can spray systemic pesticide on the roots. But do not spray any mixture on the soil because there is no telling how it will react to the soil in the long run. 

You can also use plant pins to get rid of aphids all over your bonsai tree, including the roots. These are like food sticks for bugs. It slowly releases poison in the soil or potting mixture without damaging it.

White Flies 

You can get rid of whiteflies on your bonsai tree using sticky traps, insecticidal soap spray, neem oil and parasitic wasps. But before you can apply or use any of these methods, you need to first, get rid of the whitefly infested leaves. 

Leaves that are attacked by whiteflies may contain whitefly eggs. If you do not prune or cut these leaves the eggs in them might hatch, and spread all over your bonsai. 

So, by pruning the wilted, whitefly infested leaves of your bonsai, you are getting rid of a large part of its population. Before disposing of the leaves, you should kill the whiteflies on the leaves using dish soap or rubbing alcohol.   

Next, to capture whiteflies that hover around your bonsai tree, keep glue-based or sticky traps near them. You can buy sticky traps like sticky cards or make them at home. 

For example, you can make a mixture of sugar and water in a 1:1 ratio and keep it in a bottle. If you place the bottle near your bonsai tree, the whiteflies will detect the sweet water, fly into the bottle and get stuck inside. 

Like aphids, whiteflies too die when in contact with neem oil or insecticidal soap mixture. But in case of whiteflies, the insecticidal soap mixture has to be made with dish soap and a gallon of water. If you use neem oil, get the 70% concentration version from any store. 

Spray the soapy mixture all over your bonsai tree. Do not miss spraying the mixture under the leaves. After a while, wash away the excess insecticidal soap mixture with a strong stream of hose water. It will not only get rid of the excess soap but also the dead bugs on your bonsai plant. 

Certain bugs can be used for pest control. In the case of whiteflies, beetles, lacewings, parasitic wasps such as braconid and chalcid wasps can be used. These bugs will not sting you. Instead, they will make removing whiteflies easier for you in contrast to using DIY insecticides. 

You can either buy or attract parasitic wasps near your plants. You can only attract wasps if they naturally live in your region. In that case, you can plant many flowers and plants in your garden. The nectar of these flowers will attract wasps. 

Also, parasitic wasps are attracted to water bodies and need to drink a lot of water to survive. Whether you keep your bonsai trees outdoors or indoors in a greenhouse, you need to place small containers of water near them for the wasps. 

Fungus Gnats 

To get rid of fungus gnats, you have two options, either you get new soil or reuse the infested soil by baking. The former seems easier to do, but even that has to be done meticulously. To change your fungus infested soil, first, you have to uproot your bonsai tree.

After you uproot the bonsai tree, you should wash it thoroughly. You need to make sure there is no remaining soil clinging to the roots, branches, stems or leaves. Then you need to make sure there is not a single speck of soil in the pot. 

Using stick tape to catch fungus gnats infesting a plant
Using stick tape to catch fungus gnats infesting a plant

Soak the pot in a mixture of warm water and soap to kill off any remaining fungus gnats. You have to rinse off the pot well, lest the gnats remain and infest the newly replaced soil. 

If you don’t want to change the gnat infested soil, you can bake it in the oven. Yes, you read it right. You can literally bake soil in the oven to get rid of bugs. 

Just place your soil in a baking pan and cover it with an aluminum foil. Turn the temperature up to 200°F and wait 30 minutes.After baking, you need to wash the baking pan thoroughly. 

Baking soil in the oven will not only kill gnats but any other bugs in the soil. But the whole process is tedious, messy and not to forget smelly. Your kitchen will smell terrible for a whole week. 

Spider Mites

Getting rid of spider mites is similar to the removal process of aphids from bonsai trees. You can use either an insecticidal soap mixture or neem oil to kill spider mites on your bonsai tree.

First, you have to isolate the infected bonsai tree from your other trees. Because spider mites spread super-fast from one plant to another. Then you have to create a 2% insecticidal soap mixture.

You have to mix 5 tablespoons of liquid dish soap with one gallon of hot water. Stir the solution well and make sure no suds are formed. 

colony of spider mites on tomatoes
colony of spider mites

Then, using a spray bottle, spritz the soap solution all over the bonsai tree. Pay extra attention to the axils and underside of leaves. Let the mixture sit for a while then rinse off the bonsai tree to get rid of dead spider mites. 

You should spray your bonsai tree with the insecticidal spray four to 4 to 7 days to completely get rid of the spider mites. Till then you need to keep your bonsai tree isolated from other trees.

The insecticidal soap might burn or damage the sensitive leaves of your bonsai tree. To prevent that from happening, you should spray your bonsai tree outdoors on a cool day, when the temperature is below 90°F. 

If the region you are living in has warmer temperature most days, then you should just run a test spray. That way you can check whether the insecticidal solution badly reacts with your bonsai tree.

You can also use neem oil of 70% concentration with water on your bonsai tree to kill spider mites. Azadirachtin, the active ingredient of the neem oil will destroy the spider mites usually. Just keep checking your bonsai tree for live spider mites regularly.

Mealybugs 

Mealybugs not only grow on plants under stress but are also stressful to get rid of. Because these bugs are water repellent and the usual contact sprays don’t work on them. 

You will have to use systemic sprays to get rid of them. You can also use methylated spirits to kill them. Again, parasitic wasps and ladybugs can also help you get rid of these pesky bugs too.

The white cotton-like waxy covering of the mealybugs are waterproof. That is why your DIY water sprays will not work on them. Instead, use systemic sprays such as Confidor or Orthene which will poison the food supply of the bugs and thus killing them.

Mealybugs

Since the white covering of these bugs is waxy, you can add organic oil in your systemic spray mix. The organic oil will melt away the waxy part. Whether you use this cocktail mixture with the systemic spray or not, always go for a test spray.

A lot of bonsai trees, like Chinese Elms, do not react well with systemic sprays. So spritz a leaf or two of your bonsai tree with the systemic spray and check if it damages your plant or not. 

If you want to go organic all the way, you can use organic sprays only. But you will have to spray the white waxy areas over and over again. Mealybugs are so persistent, that you may even have to repot your bonsai tree and move it outdoors. 

To cause severe damage to mealy bugs, you can use methylated spirit. Dip a brush in the spirit and dab it onto each and every bug meticulously. These bugs are tiny, so check the axils and under the leaves of your bonsai tree.

Like aphids and whiteflies, you can get rid of mealybugs with the help of natural agents such as parasitic wasps and ladybugs. The orange and black ladybugs practically live off of mealybugs.

The larvae of the ladybugs will even camouflage itself into the white waxy covering of the mealybugs to hunt them.

How to Prevent Bugs from Damaging My Bonsai Tree?

To prevent bugs from damaging your bonsai tree, you need to first know what to look out for. Only then you will know how to take measures to protect and treat your bonsai tree from their damage. 

Aphids are green, black or grey in color. Usually green in color, these bugs look like lice on plants. You can find them on the underside of leaves or on stems. If aphids attack your bonsai, you will notice that the leaves have become curled and deformed.

You might also notice that your tree has some black sooty mould like coloring on it. This occurs because ants gather around your bonsai tree, attracted by the sticky substance similar to honeydew produced by the aphids.

To prevent damage caused by aphids you can either grow a garlic plant tree or place a garlic clove near your bonsai tree. Garlic is a natural aphid repellent. It may prevent aphids from attacking or control them from further damaging your plants for a while. 

Whiteflies usually attack magnesium and phosphorus deficient bonsai trees. If your tree is magnesium deficient, you can correct it by adding a mixture of Epsom salt and water in the soil. Four ounces of Epsom salt has to be mixed with one gallon of water to create this mixture.

You can also use a seaweed spray on your bonsai leaves. This spray will prevent the whiteflies from laying eggs on the leaves by making them undesirable. You can make this spray at home, mixing water and seaweed powder. 

Fungus gnats are hard to identify as they infest the soil of your bonsai tree. They are usually grown on moist and humid soil so to prevent gnats, do not g care over water your bonsai. 

Check the soil of your bonsai tree for fungus gnats regularly, because you will want to destroy the gnats before they reach their adult phase and start laying eggs. 

Spider mites are near-microscopic and thus hard to identify. You have to check your bonsai trees regularly to spot them. To examine your bonsai tree, you should take a white paper and tap its branches on the paper. If you get red or black tiny insects running around the sheet. 

To prevent spider mites, you should keep your bonsai tree hydrated and in a cool place. Because spider mites thrive in a warm and dry environment.

Keeping you plants dry will cause them to dehydrate which is pretty deadly for spider mites. As a result, your bonsai tree will not be affected by them anymore. 

Final Thoughts on How To Get Rid of Bugs on Your Bonsai Trees

One of the biggest things to worry about on your bonsai will be infestation by bugs, the longer they last the more damage will be done to your plant so catching them soon is paramount.

If you are just learning about bonsai trees and looking to purchase high quality trees that will likely live longer than you then I would highly suggest checking out Bonsai Boy Trees as they are a long lasting New York business that provides trees for all price ranges!

Here are some of my favorite Bonsai Items

Thanks for reading this article, I have a few items I love to use with my bonsai tree care and wanted to share the best options for the core needs for the new bonsai enthusiast!

Best Bonsai For a Beginner – Most of what you find online are starter plants where they are going to be difficult to start and grow successfully. Most beginners like to have a starter plant to work from. I highly suggest looking at Bonsai Boy directly (more options and good prices), or you can look at their inventory from Amazon.

Best Bonsai Tool SetTianBonsai makes the best quality tools for simple bonsai work, if you want tools that will last you they won’t come cheap, make the right investment the first time with these beginner tools on Amazon!

Best Bonsai PotBonsai Boy’s Beige Ceramic Bonsai Pot – The team at Bonsai Boy operates out of New York and has been perfecting bonsai in the US for over 50 years, there is a reason I love and share them, if you want to order directly from Bonsai Boy then click here, or click here to order through Amazon.