Brisbane Local Food

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Hello all citrus growers!

I have just inherited 4 old orange trees (around 30 years old) and they look very sick:

lost foliage, fruit drop, stem problems (lower bark with some cracks, signs of borer and ant activity (mostly in former pruning wounds), branches with white "stuff" on them (mites, scale?) and sap coming out on one tree (collar rot??) and minor things such as leaf miner and some bugs, which I attend to with oil/soap spray. The trees were in the middle of the lawn (grass ripped away, cardboard-matted and stem-free mulched now) and had been pruned in a very uncommon way (umbrella-shaped; I can't reach a branch, many of the straight shoots left). Last season they had a bounty of fruit.

I have given them a big booster feed (citrus fertilizer, seaweed, liquid organic fertilizer and sulphate of potash over the last 2-3 weeks, before I put down the "anti-lawn-mats". I also have wrapped some sticky "tape" around the stems to stop uninvited bugs crawling up.

What would you recommend to do else and does it look like collar rot, should I apply copper fungicide? Is it a good time now to take off the straight shoots? 

Since they are my absolute treasure in a -formerly very neglected and "sterilised"- garden, I am looking for advice to save them and keep them productive. I know in this forum are some experts and I hope you can help me - the orange trees will thank you!

Thank you very much for your advice and happy gardening!




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In the meantime until people answer who have more info than I do, search this site for 'citrus trees'. You will get many pages of info but this one might be of some use to you. There have been questions, answers and photos on similar topics so you may glean some info in the course of looking over the previous posts. If you have larger sized photos, these may be some use for identification, the current ones display quite small and are just a tad difficult to see clearly.

Thank you, Elaine, for your good hints, I should follow the advices given on that post. Sorry about the pictures, they are indeed a bit too tiny... I will upload bigger ones for better identification.

Thank you, Florence, they are good hints!


Is this collar rot?


Borers and ants. Would it be good to apply pyrethrum into the wounds?


The white parts on the bark - mites or scale? What would help here?


Thank you for all your hints!

Great photos Karin! There's some experienced Citrus enthusiasts on this forum and you will get good answers to your questions.

hmm. i'm no expert, but i think:


- wound (made by mower initially perhaps? or a water split from suddenly getting lots of water - e.g. if long grass around roots was cleared away?) with perfectly healthy sap - should heal up fine? keep an eye on it to see if it has obvious insects or discolouration . colour rot generally horizontal-ish, discoloured, bark pulling away from trunk or obviously rotting

- bad one :( probably can't be saved - eaten too much of the diameter of the trunk away - unsafe for load bearing. the ants are predators of the borer - the real problem is the borer. is there fresh sawdust in the hole? are they still there? - they are moth larvae burrowed deep into the wood. suggest remove the whole limb - but you could try sticking wire down any obvious holes to squish them, or injecting derris or pyrethrum into the holes. Fill the holes with something to stop them getting back in - e.g. grafting wax or putty. ants might cause you aphid/ scale/ sooty mould problems later - can be killed with borax and honey. rub petroleum jelly thickly around trunk in a band so they can't walk up the trunk. some evidence that whitewashing the trunk deters them - they don't like it, too bright. find ant nest and pour boiling water down it. find ant nest and put the hose down it for 15 minutes (drowns the entire nest).

- lichen? suggest inspect with a magnifying glass if you suspect scale. doesn't look like it to me.


have heard people talking about biodynamic tree paste - i have no idea what it is or what it does, but it sounds intriguing. Peter Kearney is the one to ask about that I think.

Or Green Harvest sell a version of it which does perk up the trees no end. Whether it would save truly ailing trees is another matter, though.

WOW, Scarlett, thank you so much for your fantastic advice and information!!

I will follow them and see and hope.

Just one thing: Should I use the pyrethrum undiluted (no harm to tree?)to pour

into mean borers's home?

Well, I have a good idea now what check and do thanks to your help!



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