It’s the time of year to think about citrus tree borer – an irritating pest that can cause havoc with your lemons! Over the past month, I have received so many questions about this little pest that I felt it was time to revive an older blog post I wrote with my tips on how to tackle it.
Borer grubs are dormant for the next couple of months, so it is an ideal time to cut out and remove any borer. This is your time to act! Really, when it is dormant is the only time to cut it out, otherwise the grub will lay eggs on new cuts and then they will bore into the new growth of your tree.
Here are the signs you need to watch for and what you can do about it.
What do borers look like?
Borer grubs are quite big in size, and if your tree is quite young, they can take up nearly the width of the whole branch! They are fat and juicy, and half the thickness of my pinky finger, no wonder they do so much damage!!!
How can I tell if my citrus tree has a borer infestation?
A major sign to watch for is that your tree will lack vigour and have holes along the branches. In some cases, you will even be able to see mounds of sawdust on the branches and down the stem.
One of the easiest ways borer can get into your lemon tree is through a small cut on the lower trunk from a weedeater. Honestly, time and time again I have seen this, which becomes an entry point for pest and disease. If this happens to your tree, be sure to paste the wound to help it heal and to prevent pest and disease from entering.
How can I treat my citrus for borer?
The totally organic way of dealing with borer is to insert a G string from a guitar down the hole to pierce the grub, however this could take some time (and patience!).
At Grow Inspired, we typically use a squirt of CRC down the hole, as this smothers the grub and causes it to die, without harming the trees.
Following this, apply pruning paste over the holes or wounds to protect them from further infestation.
TOP TIP: It is so IMPORTANT to remember to either burn or dispose of your infected branches.
Borer can kill citrus trees if left untreated.
You can also keep your tree alive by removing the dead wood and keeping an eye on your tree, looking for new sawdust trails.
When pruning the borer out of your tree, this is an ideal time to give your tree some shape and let the air flow through the middle to prevent a wee microclimate happening, where pest and disease thrive.
How can I best take care of my citrus tree right now?
Remember to feed your tree over the winter period as it will be striving to grow, produce fruit and get ready for the next season’s growth.
Over the winter months, it is also a great idea to build up a good mulch around your citrus trees. This will help keep the water in the soil and prevent it from drying out when spring comes, as citrus have roots very close to the surface. However, remember to leave a breathing space around the trunk and to mulch right out to the drip line of your trees (where the outer branches are).
You can also grow a living mulch around your citrus. The benefits of a living mulch is that they will also attract beneficial insects, which in turn will fight the upcoming pests of spring.
An ideal living mulch for citrus include comfrey, borage, lemon balm, nasturtiums and parsley. We have just dedicated an entire bundle in my Grow Inspired Academy to growing fruit trees, where we also talk about living mulch. If you’re keen to grow or improve the health of your fruit trees, find out more here as the doors to the Academy will re-open again later this year.