How Do I Prevent Diseases And Pests When Pruning My Bonsai?

Pests and disease are something your tree is always at risk of suffering, but the risk is always higher when you are pruning your tree.

The fresh wounds expose the delicate inner layers of the tree to the elements and anything can now get into the tree very easily. While this sounds scary, it is usually nothing to worry about …but it is still something you should be aware of, so I will go through some ways that you can help your trees be protected from these types of problems when you are pruning.     

Prune Your Bonsai At The Right Time Of The Year To Avoid Diseases

Some diseases spread by spores, and these can be in the air at certain times of the year.

What is actually in the air, and what trees it can affect all depends on the time of year and where exactly you live, as well as the species of your tree, so really you need to know your tree and your area and understand if there any risk that it may suffer from.

Most trees are healthy enough for this to not really be an issue, but of course once you start pruning, you are leaving open wounds, so it can be very easy for an infection to get into the tree.

(You can read more about – How Can You Tell If Your Bonsai Tree Needs Pruned?)

Clean Your Tools So Disease Doesn’t Spread

Often we can be the spreader of the diseases, which can happen through our tools.

Really this is only a risk if we are working on an infected tree. If we cut a branch of an infected tree, the disease would get on the tool when we cut through that branch.

This then becomes a problem when we move on to prune another tree. When we cut through it, and the disease that was on the blade will now be in contact with the inside of the second tree and basically we have introduced the disease to the tree.

Ideally you are supposed to wash your tools in between trees. You can use some sort of antibacterial wipe or like hand sanitiser to kill any bacteria that may be on the tools.

The reality is that I don’t do this … and I am pretty sure I am not the only one.

I would only do this if I knew the tree had an infection, or when my tools are seriously gummed up from sap. When this happens the blades often do not cut properly so it affects the performance.

Maybe I am playing with fire by doing this, but it this is the risk I am willing to take. The advice is to clean them in between trees, so it’s down to you if you want to follow that or not.

Use Cut Paste On Wounds

Cut paste is used more for helping the trees wounds heal and reducing the scaring, but it does also have a secondary function of sealing the wound, which of course means that no pest and disease can get inside.

A tree will seal off a wound by itself, but it is not going to be immediate, where as cut paste is going help the tree block any invaders straight away.

I personally don’t use cut paste, but if you want to create a barrier to stop anything getting into your tree, then cut paste will do the job. If you are making big wounds, or you have a species that is susceptible to infection, then it could be a good idea to use it.

(You can read more about – Healing Wounds On Bonsai Trees)

Keep Your Bonsai Trees Healthy

Really the best defence your tree has to pests and diseases is its health.

A healthy tree is of course less likely to get sick, but even if the risk is higher, such as when you are pruning, they will usually be able to fight off an infection a lot easier if it is strong and healthy.

Keeping your tree healthy means it will have the energy to both heal itself and respond to any attacks that might occur. 

Pruning your tree will weaken it, so if it is already in a weakened state before you begin, it will be in serious trouble if it does get an infection, which is why you should only prune your trees if they are healthy as they are actually going to be able to handle it.

Don’t Worry About Pests And Diseases When Your Prune

For the vast majority of the time you can just prune your trees and they will look after themselves, you don’t need to be overly worried about them. So long as they are healthy, they will be just fine, especially if we are keeping the pruning pretty light.

Pruning will weaken the tree, but it should be able to deal with it and bounce right back like nothing happened without any help from you.

I think we often forget that trees are pretty resilient and if we hadn’t potted them into a small pot they wouldn’t need us at all to survive or thrive. Trees get damaged in nature all the time and they can easily heal the wounds and carry on growing, which is what they will do 99% of the time when we prune them.

(You can read more about – Frequently Asked Questions About – Pruning Your Bonsai)

Be Careful About Pruning Your Tree If Is Already Suffering From Pest and Diseases

If the tree is already infected with a pest of disease, then don’t prune it as this could weaken it further, and it may not have the strength to be able to recover from both situations.

I would deal with the pet issue first and get the tree healthy again, then consider pruning it after this.

However, I would check the advice for the individual problem your tree is suffering from first, as it may say to do differently. Certain diseases may be treated in a way that involves pruning, so I’d take that advice if it is there.

If you do end up with a disease where the advice is to prune the infected parts off, always remember to do this away from your other trees and make sure you clean up anything you remove …bag it up and bin it and then make sure your tools are cleaned afterwards too!

If You See A Problem Deal With It

If you have pruned your tree and you notice a problem starting, (you should be checking it daily) deal with it quickly. If you see any signs of pests or disease you need to work out what it is and take the appropriate action.

You should be doing this any time you see a problem, but it is even more important that you do so after pruning.

As I’ve already mentioned, the tree will be weakened by the pruning, so you really can’t delay. If you are unsure of what the problem is, Google the symptoms or ask someone, you need to work out what the problem is so you can know how to best address it.

You are probably going to have to use some sort of pesticide, but of course you need to know which one to buy, which is why you need to know what the problem is.

The sooner you can deal with the problem, the more likely your tree will survive. The longer you wait, the weaker your tree will get and the more likely it will die.  

(You can read more about – Pruning Aftercare Advice For Your Bonsai)

Conclusion

Hopefully now you can understand how to protect your trees from pests or disease when you are pruning them.

For the majority of the time you just need to keep your trees healthy and they will deal with any problems themselves, although you should still be checking afterwards just in case anything has infected your trees, and if it has, take the appropriate action to help your tree recover and get back to full health.

Pruning is usually trouble free, but there is always a chance of problems, so keep your eye out for anything until your tree is back to full health.

(You can read more about – How To Prune A Bonsai Tree – A Beginners Guide)