In most parts of Australia, if you’ve grown citrus, you’re more than likely to have come across swollen galls on your grapefruit, lemon, lime or orange.
They are caused by citrus gall wasps (Bruchophagus fellis) – native Australian insects that were originally found only in northern NSW and Queensland where native citrus grow, but they are now found in almost all states apart from Tasmania.
These small (about 2mm – 3mm) shiny black wasps are most active in spring and summer, with the female laying a clutch of eggs into the bark of the soft growth of citrus trees. As the eggs hatch, the larvae burrow into soft stems. As the larvae grow, the plant forms woody tissue around them, causing swelling and the characteristic gall. Once the weather warms, the adults hatch and the cycle starts again…with the eggs being laid almost immediately, and often in the same tree!
While the galls generally won’t kill trees, they can seriously impact their vigour, reducing the size and yield of fruit, and causing growth to be weak and spindly.
Here’s how to tackle the problem:
First identify ‘active’ galls. If the gall is covered in tiny pin holes, the wasps inside have already hatched and gone. Look for swellings where the bark is still intact.
Traditionally, galls were pruned them off, cutting the affected limb well behind the gall, then bagging the prunings, solarising and placing in the bin, to prevent reinfestation. However, in smaller trees you can lose all the most productive branches this way.
Instead, grab some secateurs, a sharp knife or even a potato peeler and, facing the blade away from your body, slice the top off one side of the active gall, or slice the gall open (like a hot dog bun). This exposes the contents of the gall (the larvae) to air and kills them, without causing lasting damage to the tree. The best time to do this is mid to late winter.
Just make sure you don’t ring-bark the stem, as this will kill it.
To prevent reinfestation:
• Don’t prune citrus in winter
• Avoid overfeeding your citrus tree, particularly in winter and spring.
• Spray vulnerable new growth of citrus trees with a horticultural oil in spring
• Keep in mind that sticky traps can kill some of the ‘useful’ predatory insects too.
• Encourage your neighbours to treat their trees too!
See the latest content from Gardening Australia as it goes live by hitting subscribe: http://ab.co/GardeningYouTube
Watch Gardening Australia on ABC iview: http://iview.abc.net.au/programs/gardening-australia
About Gardening Australia:
Gardening Australia is an ABC TV program providing gardening know-how and inspiration. Presented by Australia’s leading horticultural experts, Gardening Australia is a valuable resource to all gardeners through the television program, the magazine, books, DVDs and extensive online content.
Connect with other Gardening Australia fans:
Like Gardening Australia on Facebook: http://www.facebook.com/gardeningaustralia
Follow Gardening Australia on Instagram: http://www.instagram.com/gardeningaustralia
Visit the Gardening Australia website: http://www.abc.net.au/gardening
This is an official Australian Broadcasting Corporation YouTube channel.
********
Contributions may be removed if they violate ABC’s Online Conditions of Use http://www.abc.net.au/conditions.htm (Section 3).
37 Comments
A cordinated county wide application of systemic fertilzer sacrificing one years crop is all it would take to do them all in.
Wow Great information thnks dear👌🌷
I had them in Victoria .
Gorgeous Staffie 😉
I know this has nothing to do with lemon trees, but why did they censor the dogs junk at 4:49 by masking it over with some grass from the background?
Went through my lime tree today, worked well! A satisfying use of the peeler
I think you guys need to look into the use of kaolin clay
I wish i'd seen this earlier 🙁 i completely pruned back my Tahitian Lime tree to just its stem and 2 branches and i'm scared ive killed it :/
Thanks Jane, I will try this. Louie is gorgeous ❤
Love it
Wonderful. No more having to prune back the tree heavily and no more of those yellow sticky tubes form Bunnings.
Thank you pretty lady
Thank you! I saw this video randomly a few weeks ago and watched it, not thinking much of it. Imagine my surprise today when counting lemons on my Meyer dwarf lemon tree when I discovered huge falls today. I followed your trusty advice and have potato peeled the galls. Fingers crossed they won’t be back
Thanks for wonderful idea, simple but effective.
Ur companion I m in lov with him
What do you do at this time of year when they’re hatching? The tree in the yard is far too big to possibly shave them all
Hi, thanks for this vedio, but I am too late I just cut whole of my lemon tree
Could you please tell us how to get red of Fruit flies… They are absolutely annoying and they hurt so much when they bite us… Yes we got them inside the house too…
Could you please help us.
Thank you! It's never ending.
This method is not suitable for WA and it’s not what the Agricultural department of WA has been asking people to do. I wish that Gardening Australia has been more specific with their advice and actually mention it’s not applicable everywhere. This pest is relatively new to WA, they are still trying to stoop it from getting into the WA citrus industry. The problem with the potato peeler method is that it only lowers numbers since you can’t peel the whole gall without ringbarking the branch. It does not eradicate them from a tree and every hatched wasp leads to heaps more galls. I am constantly having to educate WA people on social media who are following this bad advice. Thanks a lot for that Gardening Australia! You have made this problem much bigger in WA by forgetting we are not the same as the eastern states…..
WA Dept of Agriculture, advised me to prune and keep prunings in a sealed garbage bag. Then solarise it for at least four weeks.
Spray regularly with Vasilli’s GWS
Thanks 👍👍👍👍👍
Can you shave it any time of the year
this appeels to me
Can I still do this in Melbourne late January
Thank you, i have been peeling these galls for three years.
Love the dog too.
You are always full of great info Jane. Thank you for easing peoples concerns about their lemon trees again. 🍋
You'll never win like this
Darn I already chop all of the infected areas off. I wish I had found your video before I cut it. I read multiple website saying to chop them off.
How to get rids of ants?
And how to get rid of aphids?
Louie is a cutie pie!
I just pruned half my lemon tree was going to prune the next half, now what do I do now 🤷♂️
Thanks so much definitely try this one. My lime tree is badly affected. Good job 👍 thanks for sharing
So the bits shaved off just go in the rubbish and not the compost? Is that right