Cabbage Tree 'Sudden Decline'

akl439, Dec 26, 3:37am
One of our huge cabbage trees is losing all its leaves and looks seriously ill.My neighbour also has one that has lost all its leaves.Looked it up and it seems like it's 'sudden decline', but can you do anything to save them!Seems to have water coming out the lower trunk.I think this disease struck a few years ago, but not sure what to do about our trees.We're in a suburban garden.Any suggestions appreciated.

deathrockboy, Dec 26, 7:23am
I don't think there is anything you can do to stop it killing your tree, The disease which causes sudden decline is spread by sap - i think that passionvine hoppers and sap sucking insects are considered to be the main vector. If you cut the tree down you should carefully sterilize your tools to prevent any healthy trees becoming infected.
You might try contacting MPI as they might be able to test it and confirm the disease is present but you'll probably have to remove the tree before it rots and falls over. Spraying with something to prevent insects feeding on the infected tree and spreading it to healthy ones might help save other trees close by. The disease might spread to or be found in flax plants too but i'm not sure about that.

akl439, Dec 26, 6:59pm
Thanks for that information.I will have to get someone in to take the tree down as it's so large.We do have truckloads of passionvinehopper here.I will give MPI a ring as they may be interested to know that the disease is in this area.Thanks again for your advice.

mokoni, Dec 26, 10:08pm
I'm sorry to hear about your cabbage tree's sudden decline. It can be tough to see your beloved trees suffer like that. But don't worry, there are a few things you can do to help them recover!

First off, it's important to understand what might be causing the problem. The fact that water is coming out of the lower trunk could be a sign of root rot, which is a common cause of sudden decline in cabbage trees. This happens when the roots become waterlogged and start to decay, which can lead to a lack of nutrients and oxygen for the tree.

Another possible cause of sudden decline is a fungal infection. This can be spread through the soil or by pruning tools that haven't been sterilized properly. Look for signs of fungal growth on the tree, such as mushrooms or black spots on the leaves or trunk.

Once you have an idea of what might be causing the sudden decline, you can take steps to help your tree recover. Here are some tips:

Improve drainage: If your tree is suffering from root rot, improving drainage can help prevent further damage. Make sure the soil around the tree isn't waterlogged and consider adding some gravel or sand to the soil to improve drainage.

Remove affected branches: If you notice any branches that are clearly affected by the disease, prune them off as soon as possible. This can help prevent the disease from spreading to other parts of the tree.

Apply fungicide: If you suspect a fungal infection, applying a fungicide can help kill off the fungus and prevent it from spreading. Make sure to follow the instructions on the label carefully.

Keep the tree well-watered and fertilized: Even if the tree is suffering from root rot, it's important to keep it well-watered to prevent further stress. You can also add some fertilizer to the soil to help the tree recover.

Monitor the tree closely: Keep a close eye on the tree over the next few weeks and months. If you notice any new symptoms or signs of decline, take action as soon as possible to prevent further damage.

Remember, the key to saving your cabbage tree is to act quickly and decisively. With a little bit of care and attention, you can help your tree recover and thrive once again. Good luck!

deathrockboy, Dec 27, 8:25am
They often have moss on the lower trunks and it won't do any harm.
I'm not sure what you mean by "water underneath" though. You mean the moss is wet! Or the bark is flaking off and the bare stem is weeping liquid!
The main symptom of sudden decline seems to be heavy flowering followed by the leaves yellowing and falling off.

scruff71, Dec 27, 9:30am
I took out all the flax and reduced the cannas because they seemed to be the main hosts for passionvine hopper on my property in Auckland.Last year I noticed a reduced population of these insects had infested a large mint patch but were not a problem so I will monitor this with interest this growing season.
Our cabbage tree bought for $1.00 from a popular Mangere plant nursery is 32 years old and continues to be healthy.It is watered with worm tea periodically and stripped of the yellowing lower leaves weekly.

tune, Dec 31, 1:04am
Sudden Decline - the disease that has killed large numbers of our iconic native cabbage tree Cordyline australis, also known as ti kouka. Highly sensitive DNA techniques and electron microscopy found the culprit was flax yellow leaf phytoplasma (Phytoplasma australiense), an elusive bacterium that lives in plant sap and is transmitted by a sap-sucking insect. This discovery has also led to recognition of the same parasite in other plants including the native karamu (Coprosma robusta) and in strawberries.
The disease is not caused by a virus but by a specialised bacterium called Phytoplasma australiense and is probably transmitted by a sap sucking insect vector (possibly the passion vine leaf hopper).
Dr Ross Beever said that cutting the sick trunks back usually doesn't work, but occasionally you can be lucky. You often get re-sprouts which collapse and die after reaching a metre or so in height ??