Dead/dying robinia

[Quercus-90]

Hi All,

 

Customer has a small robinia in a sunny spot. It has died out on top completely, but there are new buds breaking on the stem. For the time being I have removed the dead top to see if I can encourage what's left to re shoot.

 

On inspection of the tree, I found this

Gatherings of what at first I thought was red spider mite ( but not sure now!)

 

In the same bed there is a small ornamental acer, (full sun so not ideal for acer?) which has also died out on top completely! But has foliage and new groth lower down the stem.

No sign of the pest on this tree tho.....

My thoughts on the acer are possible frost damage?

 

any ideas chaps??

 

 

 

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[Jesse]

Its going to die, lots of dead Robinia around its a vascular problem which could be to do with climatic conditions or could be an epidemic problem others will pass comment, for me I really think its a vascular problem, 99% of the dead and dying sp in my area , somerset are attributable to heavy crown reductions , which then appear to recover in the next season and then quickly decline soon after spring flush, common symptoms the bark on affected trees will lift ( Tap it first ) and smell of urine when lifted . Its something we are importing on stock from abroad.

[treedom]

Seeing lots of robinia dying this year. For last two years they lost bits off their crown now dying completely

[sloth]

One could be forgiven for thinking it's a Nectria sp...

[Paul Barton]

Around these parts it has been the 'Frisia' that have choked it. There was a thread on it before I seem to remember (http://arbtalk.co.uk/forum/tree-health-care/8148-robinia-problem.html).

 

It would be interesting if others of the species also start to die off as well now...hopefully enough to prompt someone to research exactly why it is happening.

[Stubby]

I once felled one and left the stump and within a few years it was back up to gutter height of the house ! No accounting !

[Quercus-90]

Thanks so much for everyone's replies, I had no idea about this issue!?

I have other customers with robinia so will warn them!

 

This one is/was a Frisia!

 

Anyone have anymore detail on exactly what's causing this? Of us it one of those "it could be" kind if situations?

 

Anyone agree in the acer? Frost damage + not enough shade?

 

 

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[Tony Croft aka hamadryad]

Around these parts it has been the 'Frisia' that have choked it. There was a thread on it before I seem to remember (http://arbtalk.co.uk/forum/tree-health-care/8148-robinia-problem.html).

 

It would be interesting if others of the species also start to die off as well now...hopefully enough to prompt someone to research exactly why it is happening.

 

ditto:thumbup1:

[Quercus-90]

Hi mr croft! Been waiting for you to crop up

Firstly, your post on the matter is hugely interesting! I take my hat of to you sir!

With the Frisia I have affectively pollarded it below the graft, so I will see if any of the buds down the stem developer further.

 

Any pointers as to what's got me acer!?

Best I can remember its acer palmatum

 

If I dig up to remove I will check roots.

 

 

 

Quote:

I think we can make some educated guesses. Armchair dendrology / pathology if you like.

 

 

 

We know that only the Frisia variety seems to be affected. So it seems reasonable to infer that this disorder affects Frisia because its Frisia. (Seems simple huh, but normally correlation does not mean causation.)

 

 

 

So what's different about Frisia?? As Lee's link reminds us; its a grafted variety and its got yellow foliage. It was created by cramming a bit of a naturally occuring yellow sport into the rootstock of a normal R. psuedoacacia.

 

 

 

Yellow leaves are yellow because carotenoids are reflecting more visible light than the cholorophyll which is present at lower levels than green leaves - they photosynthesise at a slower rate. Traditionally "yellow" plants / trees are considered less vigourous than their wildtype counterparts.

 

 

 

It seems reasonable to infer that less vigour means a reduced ability to compartmentalise as well as slower growth.

 

 

 

A vascular wilt fungus clogs and blocks xylem vessels as it is transported (typically from the soil) around the tree. Robinia spp. are ring porous so to begin with, any damage caused by such an agent affects a greater percentage of active vessels.

 

 

 

We can there surmise that perhaps the normal Robinia pseudoacacia might have sufficient vigour to compartmentalise any damage and even grow additional vascular tissue over a longer/earlier growing season.

 

 

 

Its interesting that the RHS info suggests that it would be a surprise that such an agent could pass through the "graft barrier". What barrier? The tissue is fused?

 

 

 

Additionally, lets not think of this disease attacking and affecting different trees. Frisia is probably a graft clone. As a clone, if one tree can be affected...

 

 

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[treeseer]

Anyone have anymore detail on exactly what's causing this?

 

The question is, what are those orange-red bumps? they resemble nectria cinnabarina but darker, and they sure are packed together tightly. in the US it is a Very weak pathogen/saprophyte, so it's likely a secondary issue.

 

if those are graft unions then the grafts failed, and i agree that is not an insurmountable barrier.