UKTC Archive

Re: Red-belted Clearwing moth

Subject: Re: Red-belted Clearwing moth
From: Jerry Ross
Date: Jul 29 2019 13:01:47
Philip -
My suspicion is that this may be a short term irruption of the moth, so it's more how to deal with the tree (thanks for your suggestions) as much as the insect itself.  So I think improving the tree's general vigour (removal of competing weeds, mulching etc, and indeed restoration pruning, if appropriate - I haven't seen the tree) is probably the best way to go; but any further suggestions would be welcome.

While the moth has been associated with trees with pre-existing problems (which is what I assume you mean by it being 'mainly secondary'), it's also reported that "The common feature of the damages in France and in Hungary is that in both countries the high abundance of the clearwing moth was observed in regularly pruned but otherwise intact, healthy trees "  (See here: )

Currently it seems it's mainly a problem in Europe with most of the research I could find coming from eastern European plus Turkey, as well as some from N America; but who knows, perhaps rising temperatures will make it a more frequent feature in the UK, where presently it's described as 'Scarce  B'.
(Which  I had to look up:
"Nationally Scarce (Notable) Category B:  Taxa which do not fall within Red Data Book categories but which are uncommon in Great Britain and thought to occur in between 31 and 100 10km squares of the National Grid or, for less well recorded groups, between 8 and 20 vice-counties. )


On 29/07/2019 10:48, Philip Wilson wrote:
Jerry - no experience, but some speculation. A chemical or biochemical remedy 
is probably undesired, and anyway I gather that any one-year larvae (the 
larval stage is two years) would be difficult to reach with pesticide.

So I might suggest, if the aim is to conserve the tree, removing the dead and 
unthrifty limbs in the manner of restoration pruning. But whether that would 
reduce local population numbers, and whether that in turn would reduce future 
damage given that the pest is mainly secondary, is questionable (it would be 
interesting to explore whether there is evidence of the pest in healthy 
bark). Such a hygiene operation might be set against the value of the habitat 
features associated with the dead bark and wood if left in situ.

But it is more likely that the tree is very old and the damage is either 
largely already done or largely inevitable. Even if the damage extends to the 
trunk the crown can be retrenched to an appropriate extent, and if the tree's 
prospects are really poor, and it has individual sentimental value, it could 
be grafted to give a succession.


-----Original Message-----
[] On Behalf Of Jerry Ross
Sent: 29 July 2019 09:32
To: UK Tree Care
Subject: Red-belted Clearwing moth

Anyone have any experience of the damage caused by this otherwise rather 
interesting moth?
They are on an old apple tree in a historically interesting orchard- The 
owner writes:

"one of our apple trees (is) infested with red-belted clearwing, Synanthedon 
myopaeformis. I managed to get a picture of a late straggler before it took flight or 
we’d have struggled to work out was going on.
There are lots of empty cocoons sticking out from the bark and a lot of the 
bark is breaking away. Clearly the larvae have done a lot of damage below the 
Any thoughts on how best to treat this to save the tree?"

The best I can say is try to increase the tree's general vigour.
Any more helpful suggestions?

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