Help! Our Paperbark trees are all dying! WA, Australia. -- Photos included

jodylicious

I just moved out to a property in the northern part of WA, Australia, about halfway between Broome and Darwin. The property has about a dozen Paperbark trees (Melaleuca), many of which are dead or dying. Most of the neighbouring trees of other species are doing fine, but the Paperbarks are suffering some sort of disease/infestation.

I don't have pretty much any experience with Paperbarks, but I'd like to save the remaining trees and nurse them back to health. I've taken some photos to show the damage, so if you recognize what the problem might be, please let me know.

This first photo shows one of the rows of trees. They get a pretty decent amount of water, and have been around on the property for quite a while. It's only in the past year (I'm told... I just moved here) that they've started dying like this. Most of the trees in this row are still alive, except the one on the far right of the photo. Even the still-alive ones are not putting out as much foliage as expected.



This photo shows some little tiny holes in the trees. Each hole is only a few millimeters in diameter (as visible on the surface) and don't really look too suspicious on the outside like this.



When the bark is peeled back, however, it seems that there is much more damage underneath, including tunneling/boring. Whether it's some sort of beetle or other insect larvae or something, I can't tell... there are no eggs/insects/anything left in the holes. These holes are along the trunks, branches, and even into the roots of the trees.



The more deeply the bark is peeled back, the more serious these spots begin to look. At this depth (just before the actual wood of the tree) the holes are almost a full centimeter across in places. They also seem to be filled with what looks like soil or rotted plant material. It's a rich, moist, black substance, that just seems like potting soil or compost.



On the trees that are still living, there is still some sparse foliage. Some of it seems to have these spots on the leaves. I don't know if it's part of the cause, or if it's a result of the holes. Maybe it doesn't even have anything to do with it.



On the same limb, but a different branch, there are leaves that still look perfectly normal too.



Any ideas, comments, suggestions, or advice would be greatly appreciated. I'd like to save the remaining trees, so if you recognize the damage as something that can be prevented in the still-alive trees, that'd be ideal.

I checked under the bark on a small section of one of the still-alive trees, and there doesn't seem to be this damage. One of the trees was half dead, half alive, and there was the damage on the dead side, and not on the living side, so I'm pretty sure this is what's the matter. It's just a question of how to treat it. Should I get rid of the dead trees, or is it already as bad as it's going to get?

Thanks for any help.
~Joe

Eric Frei

First of all I'd like to say, well presented.

Now, what we have not established is that the borer holes are a primary or secondary pathogen.

Often I find them a secondary, which means as the tree declines and dies they do their job, but the decline came first and not from them.

As they are all getting it we can assume it's a species specific problem.

I had a similar situation here about a year ago. I wasn't sure what the problem was but knew how to fix it.

Put it this way, your MD prescribes penicillin to ward off an infection, he does not have to know exactly which bug it is does he (and often they dont)?

I would recommend you do a basal drench to the drip line with confidor, water it in.

I would also do as best I could a foliage spray at the same time (wear PPE).

Now that helps nail some bugs but does little if it's a fungal attack. It could be right down at the roots the problem lays, I hope there's no fruiting bodies and mushrooms hanging out of the tree's trunk at ground level etc.

Anyway, two types of fungal treatments are required.

1/ Antagonistic fungi to wage war on bad fungi (trichoderma)
2/ Mychorizal fungi to coat the root hairs and increase absorption to the tree.

Apply them both liberally.

Then do soil treatments with Seasol etc and mulch the drip lines.

With the paperbark I treated I did the same, 3 months later was back to a ripper tree.

For the record, confidor does not kill fungi so the two can be used together for a double knockout blow to pathogens. Confidor is also one of the lessor aggressive chemicals for environment.

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jodylicious

Why thank you! I take pride in my work!

Thank you also (and more importantly) for the info on rescuing these trees. I will be getting started on the resuscitation efforts immediately.

While on the topic; Would it be best to cut down the already-dead trees? I don't think we'll be getting them back, and I don't want to keep them around if they're going to spread any sort of infection.

What about the trees that are half-afflicted? Is it okay to leave the living half and take off the dead half? Will the still-alive part be likely to survive at this point, or is it safer if I remove them before they spread anything that they might have caught from their deader-half?

Thanks again,
Joe

Eric Frei

Yes, get rid of the dead trees, and prune out dead wood. Prune to target (AS4373) but it's harder with paperbarks to see the target.

If pruning deadwood out, it's also a tough call to make when it's a leader coming off a multiple stems to the ground. Good Luck!

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jodylicious

Hello, and thank you again for your assistance with this. I've just found a supplier that can send the Confidor out to me.

In the meantime, I was just wondering if you could clarify the Basal Drench procedure. As I understand a basal drench, it's when you dig a shallow trench (10cm, for example) around the base of the tree, and pour the treatment into that... kind of like a moat.

You said to do the basal drench out to the drip-line, but this is where I need a little more info. Do you mean to create this trench at the drip-line and put the Confidor in there, or should I simply be saturating the ground from the base of the trunk all the way out to the drip line?

Thanks again,

~Joe

Eric Frei

What you have described with the moat is called a collar drench.

Get a watering can and water the ground (with confidor and soil treatments) all the way out to the drip line.

Saturate the ground, many watering cans.

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jodylicious

Excellent, thanks for the clarification. I hadn't done a basal drench before, so when I looked it up, a video came up on youtube of someone doing the collar drench, but they listed it as a basal drench.

Thanks again,
~Joe

Eric Frei

Collar, basal, dang terminolgy .... if I said dripline drench what then.

Anyway, you know what to do, I cant say online anything else other than apply at label rates, but you know, tests have shown that a way stronger concentration is required for soil drenches.

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nicmando

Hi,

We are having a similar issue with a paperbark on our property. First the flies came and bored the holes into the tree in about October 2011, then over Xmas all the eggs hatched, and the tree and yard were inundated with worms, who then ate every leaf off the tree. It's the beginning of Jan now, and I'm concerned the tree is beyond help, with the highest summer temps still due.

Did you have success with the treatment you were prescribed.

Thanks
Nic

Alphajaffa

whats the soil like up there , Im in perth and its high in silicate down here , makes it water repellant , if its the same up there you may need to wetta soil first