From the Garden with Fi Morgan: A few things about citrus trees

From the garden with Fi Morgan talks about growing citrus in the bellingen Shire and the common pests and diseases.

It’s the time of the year when citrus trees are laden and you can barely give the fruit away.
As there are entire books devoted to caring for citrus and I have about three paragraphs, I’m just going to point out a few basics. Even so, this will be a part one and part two arrangement.

Gall Wasp. This is an important community announcement. There is no cure whatsoever for gall wasp. It ‘s a native of the Australian finger lime and it bores into a branch, lays eggs and then the hatched larvae feed on the inside of the branch which causes a lump. When mature they exit the lump, fly off and repeat. The tree gets weaker and weaker and fruits less and less with this repeated cycle. The recommended way to prevent it maturing and spreading throughout your citrus tree/s AND YOUR NEIGHBOURS (we are all connected) is to cut the gall lump out and burn it asap.  There are some encouraging experiments with kaolin clay to prevent the wasp from laying in the first place. They love new sappy growth.

Scale. Citrus are prone to this pest. Check the underside of leaves, check stems and veins and the fruit for innocent looking bumps that at first seem to be part of the plant but are actually adhered pests. Scrape them off. Plant too big? The suggestion is to make a white oil – kitchen oil with detergent or soap mix which works by smothering.

Powdery Mildew. A black powdery fungus that is harmlessly telling you the tree is infested with an insect pest such as scale, whitefly or aphids. It grows on their ‘honeydew’.

Bronze Orange Stink Bug. Sap sucker that causes the tree to drop fruit. If that’s not bad enough, it shoots awful smelling citric acid when threatened which can damage your eyes and skin. The drongo bird is the major predator of stink bugs but you may have to resort to picking them off with tongs or an old vacuum (while dressed for nuclear fallout protection). Young ones and eggs can apparently be knocked over with a white oil concoction.

Orchard Butterfly (Papilio aegeus). Oh so pretty! The caterpillar does prefer to feed on citrus leaves but unless there are tonnes of them it’s not a problem. As butterflies they are pollinators for a lot of flowering plants.

Finally! The Bello food growing podcast is starting Thursday July 30 at 4pm. We dive into a topic you’ve suggested, with a local expert. You get to ask real live related questions. Then we have an open Q&A for your seasonal growing questions, and community announcements related to food growing (spare seeds? Looking for something?). Yes it will be recorded if you can’t make the live session.
The first two episodes will be entirely free. Ongoing will be a pay-what-you-can model from as little as $1 a month to cover running costs.
Last Thursday of every month. 4pm during winter.
Put it in your diary. Go here to register your interest to receive the Zoom link & password.


Just in case you’ve missed Fi’s previous tips ‘From the Garden’………

Edible Weeds

Last Chance for Snowpeas

Pigeon Peas Are The Go

It’s Time for Fruit Trees

All Things Brassicas

Planting for Winter in the Bellingen Shire

Where to Place Your Veggie Bed

Building a Garden

Feed the Soil Part 1

Feed the Soil Part 2

What Grows Well in Pots

And don’t forget to check out Fi’s stunning artwork- the Garden Series HERE


  • Lindy says:

    Regarding the gall wasp. I saw on gardening Australia that, if you use a potato peeler and strip some of the bark from the gall, it exposes the larvae and they die. Have you heard of/tried this?

    • Fi says:

      No I haven’t heard of it, but I haven’t heard of every gardening trick!
      While this would kill the larvae so they don’t hatch and move on to create more havoc, the damage and weakening of the tree has been done by their burrowing. I guess it saves chopping a big limb off, though I’d be investigating ways to help heal the bore holes.
      The best solutions to look for are ones that prevent the gall wasp laying in the first place.

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