Another Garden question - what is killing my citrus trees?

[i-need-a-martini]

About 6 weeks ago I noticed a couple of the branches on the orange tree had no leaves and it looked like something was burrowing under the bark eating it away as it went. We then went away for 3 weks and by the time we got back, the whole tree was infected.

It had no leaves or oranges this year at all.

It is sending up new branch shoots even on the branches being affected but I am cutting it back hard anyway to try and save what I can.

Whatever it is isn't leaving borer holes or any pattern.

I have just noticed my mandarin has one branch starting the same so clearly an infestation of some sort.

I can't see any bugs at all and I haven't found anything on the internet.

Any ideas?

[imastawka]

Citrus Gall Wasp probably.  Do your branches look like these?

 

You will have to cut them all off.  Don't put them into compost.

Seal them in plastic bags and into the garbage.

Trouble is, the blighters will be back.  You need to prune them out

before they hatch - before spring.  If neighbours have citrus and

don't prune, then you'll get them every year, no matter what you do.

Sorry.

[i-need-a-martini]

No doesn't look like that. No lumpy bits.

Its as if the branches are shrivelling and drying.

[bobbelgra]

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@i-need-a-martini wrote:

No doesn't look like that. No lumpy bits.

Its as if the branches are shrivelling and drying.

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sudden death.See it a lot in orchards if it is the same thing.They just end up dying.

http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0008/138185/Managing-sudden-death-in-citrus.pdf

[imastawka]

Wow,  I hadn't heard of that one.

[lloydslights]

http://www.abc.net.au/gardening/stories/s2246721.htm

Martini, could it be root rot?

I was initially wondering whether there was a pine tree nearby, or whether mulch had been applied too close to the trunk thereby introducing favoured conditions for fungus. 

I don't know what to do, though.  

Mention is made within the above article that it may travel from plant to plant via the roots contacting.

DEB

[i-need-a-martini]

It almost sounds like it. The death starts on the tips and works its way through the crown.

But none of factors are the same - I'm on good loamy soils, drainage is great, there are no fungus growing around the ground/root (there is no mulch or any other tree around either citrus).

I haven't noticed that the dead branches smell like 'rancid coconut'. I'm off to check that now...

(not that I know what a rancid coconut smells like...)

[i-need-a-martini]

No rancid coconut smell. Not even a citrus smell.

It's a mystery...

[imastawka]

“mal nero” referring to internal wood browning

???   Maybe??

http://idtools.org/id/citrus/diseases/factsheet.php?name=Mal+secco

[olivervcdad]

That sounds closer to it.

But the disease is not known to occur in Australia?? Plus it is mainly a disease that affects lemon and the lemon near it is fine.

This is very odd.

I've cut both trees back really heavily today so it will be interesting to see what happens over the next few months.