Defoliation of Ash

[Russell Miller]

Anyone else seeing major defoliation of ash by insects this summer? Leaves eaten to midrib. Semi circular holes. Got to be caterpillars but I’ve not seen such dramatic defoliation. A number of large early mature trees in Richmond.

[Stubby]

24 minutes ago, EdwardC said:

Ash sawfly? Sight of the critters would help.

What with that and Chalara  they are doomed !

[daltontrees]

2 hours ago, Russell Miller said:

 

Anyone else seeing major defoliation of ash by insects this summer? Leaves eaten to midrib. Semi circular holes. Got to be caterpillars but I’ve not seen such dramatic defoliation. A number of large early mature trees in Richmond.

 

Aroun Glasgow there is a fair bit of this. Alos I watched pigeons sitting at the top of my neighbourign ash trees as they came into leaf ripping the young leaves off. Plus it was so dry some of the buds didn't even open this year. Public and clients are assuming it's Chalara, but I'm not seeing many symptoms of Chalara, just lots of awful looking ash.

[daltontrees]

13 hours ago, EdwardC said:

Awful looking ash is a symptom of Chalara.

 

Long before Chalara was known of, Ash Dieback was a thing. Abiotic. General decline for reasons not fully understood. The ash I have been seeing look awful but have no symptoms that can only be Chalara. How, for example, is it possible for Chalara to cause a well-set bud from a previous year on a good sturdy twig to fail to develop at all?

[Stubby]

3 minutes ago, daltontrees said:

Long before Chalara was known of, Ash Dieback was a thing. Abiotic. General decline for reasons not fully understood. The ash I have been seeing look awful but have no symptoms that can only be Chalara. How, for example, is it possible for Chalara to cause a well-set bud from a previous year on a good sturdy twig to fail to develop at all?

I have thought this . I agree that Ash have always " done what Ash do " ( as someone once posted on here )  .

[daltontrees]

Quoting directly from "Diagnosis of ill-health in trees' by Strouts (1994) -

 

"Fraxinus excelsior suffers from a condition, not fully explained, called Ash dieback. It has not been clearly characterized but involves the death of scattered twigs, branches or limbs.Even severely affected trees sometimes slowly recover."

 

A pessimism in the industry about Chalara is sweeping the country possibly faster than Chalara itself. But if you stop and look at an ash closely in some areas you may find no wilted leaf, no diamond shaped lesions, no fruiting bodies on last year's fallen petioles, no specific discoloration under the bark, in fact no evidence of Chalara whatsoever.

 

I recommend people stop and actually look instead of assuming from a general impression of tattiness. As Shigo used to say "Touch Trees".

Edited August 16, 2019 by daltontrees

[daltontrees]

I crossed this country (Scotland) yesterday, it's not everywhere.

 

I'm not at all convinced that dieback in ash at the very peripheries which could be explained by the drought we had during leafing in late May (and last May too), but with no classic signs of Chalara, is Chalara.

[benedmonds]

I had only seen one "possible" case locally last year and also believed people were getting "over zealous" in the identifications... but this year I have been to places with numerous dead trees. On a bike ride a few weeks back it felt like I was at a front line. The ash close to home are still ok but as I got into Leicestershire there were many mature trees with symptoms.. 

[daltontrees]

10 minutes ago, EdwardC said:

According to Forest Research it is. And that's been the case for a few years.

 

As mentioned before it can exist at low levels without being so bad it sticks out. Then when the innoculum reaches a certain level it very quickly becomes blindingly obvious.

 

Nobody noticed it for the 8 years prior to 2012 that it had been present. It was only when people were alerted and started looking that they began to see it.

The symptoms are not everywhere...

 

Then map shows no recorded cases in the area (Ayrshire) I was surveying in last week, or in a couple of the areas I visited yesterday.

 

UK_chalara_outbreak_Map_Web_Version_5July2019.pdf

[daltontrees]

You're not going to concede anything, are you, even on a site that I have seen and you and FR haven't? I know what I saw, and I now what I didn't see. I may have faults but not paying attention to detail is not one of them. The trees I saw were dead at the tips, there were indications that this was a result of lack of water and other abiotic factors including salt and constrictions from planting grilles, there were no symptoms of Chalara, it would have been professionally negligent of me to report Chalara, and if I had I would also have notified FR, especially since there isn't another reported square within 50k. And I would also consider it a grave disservice to society to recommend that the trees not be retained on the basis that they might have or will inevitably contract Chalara. These might be the tolerant or resistant populations that we need.

 

Back to the OP. There are shabby looking ash around whose condition is not a result, primarily or at all, of Chalara. Even FR has produced guidance that includes a list and photos of symptoms associated with other disorders of ash.