Why are the leaves on lemon tree curling up?

[Makita]

   

I have a lemon tree. About 50% of the leaves are turning yellow. Does it mean nutrient deficiency? The leaves are curling up. The tree is more than 15 years old. Thank you.

[JacobZ]

Hi @Makita,

Thank you for your question about your lemon trees.

I suspect this could be because of a nutrient deficiency, over or underwatering, pests or a combination of these but I can't be certain.

Is it possible to get two additional photos? One of the whole tree and one of the base of the trunk? This will help our members see and understand the issue and offer their best advice.

Do you water the lemon tree regularly? Do you apply any fertiliser or products to the tree? Have you noticed any small insects or pests recently? Is this a new issue, and if so, has anything changed recently that could've caused this?

Allow me to tag @Noelle and @mich1972 to see if they have any thoughts.

You might like to read through How to diagnose a sick plant and How to determine soil health for some further information.

How To Grow And Care For a Lemon Tree will also be worthwhile.

Let me know if you have any further questions.

Jacob

[Makita]

Hi @JacobZ 

I water the tree once every 2 weeks. I use blood and bone. I cannot recall the tree was attacked by insects for the past few months.

I am attaching more photos here.

[bergs]

Hi @Makita 

In one of those photos I can see Citrus Gall Wasp nodes on your tree.

In the photo you have trimmed it after the gall.

They need all the galls removed altogether and either burned or put in the rubbish and then set some Citrus Gall Wasp traps in and around your tree.

The wasp lays eggs in the young branches and when hatched eat on the wood from inside, thus causing the galls.

If there are little borer like holes in the gall, it means they are gone, but still cut them back to behind the gall.

In the warmer weather the tree may need watering more than once a fortnight. 

Citrus are gross feeders and hate to dry out. check the soil around the area to see if it's dry before you water.

A good feed of Citrus Fertilizer once a month during the growing and fruiting season should give you good results'

Cheers @bergs 

[Makita]

Hi @bergs 

I shall follow your instructions. Hope I can save my tree. Thank you. Appreciated.

[JacobZ]

Hi @Makita,

Great pickup @bergs, thank you for that. 

I see what you mean in the 2nd image, this definitely looks like the likely culprit.



Bergs' advice is brilliant, I'd suggest inspecting the tree and removing any of these nodes and disposing of them.

You can also hang some of these Go Natural Citrus Gall Wasp And Medfly Insect Traps around your tree to help.

You might like to have a read through How To Control Citrus Gall Wasps for some further information.

Let me know if you have any further questions.

Jacob

[Noelle]

Hi @Makita 

The citrus gall wasp galls will not be the cause of the leaves drying and curling - that looks more like a damage (broken branch?) or watering issue to me.

As the tree looks to be quite old, and there are ample strong new growths coming from just above the graft union above the soil, you can be quite ruthless and cut off most of the older branches above this level, and effectively 'reset' the tree to start growing ll over again. I have now done this three times with a lemon tree that is over 60 years old (or at least the trunk is), and it has recovered well each time and is still producing good crops of juicy lemons.

[robchin]

Hi @Makita 

First thing I notice is that you, like many others, have Citrus Gall Wasp in your trees. This will do lots of damage to your trees by limiting the movement of water and nutrients up and down the tree. Good info here on that for you: Search results - Bunnings Australia

There is also some good info on Citrus Leaf Curling here: What do you do about citrus leaves curli... | Bunnings Workshop community - generally it's a sign of stress. CGW may not be the only problem. 

Good luck.