Hornet moth (Sesia apiformis) in the Midlands

[Al Duffill]

 

Hi,

A couple of pics taken today of two Poplars, one has dropped its leaves already the other, next to it, isn't far behind. I believe the exit holes were made by the Hornet moth, I have crossed referenced including the AA's P&D handbook (2013)which states the moth has only been found South of the Midlands, I live in Redditch, Worcestershire which is definitely the Midlands. According to what I know the moth is usually a secondary agent to the decline of Pops but there have been suggestions it could be a primary.

 

So, has anyone more info about the moth and has anyone seen the moth or exit holes further North?

 

 

 

 

 

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[David Humphries]

I've only seen evidence of it in East Anglia so can't offer anything on its progressive spread.

 

http://arbtalk.co.uk/forum/tree-health-care/41768-poplar-hornet-moth.html

 

I'd imagine Nigel Straw at Forest Research would be particularly interested.

He co-wrote a paper in the AA journal a while back

 

Arundell, J.C. and Straw, N.A. (2001). Hornet clearwing moth (Sesia apiformis [Clerck]) and dieback of poplars in eastern England. Arboricultural Journal 25(3): 235-253.

 

Contact details....

 

Forest Research - Nigel Straw

 

.

[slack ma girdle]

According to Skinner (British moths) it is ' locally widespread in the south east, Berkshire, Oxfordshire, and east Englia. It has been recorded as far north as Scotland, but not recently.

[Al Duffill]

Thanks guys, I read a piece by Nigel on the FC site already, interesting stuff, I will contact him. I reported the trees to to our Arb Officer, he wants them taken out as they are next to property and a road.

 

 

 

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[Al Duffill]

Thanks David for the link, I got in touch with Nigel and asked a few questions about the moth, here is his reply.

 

Thank-you for your email and report of hornet clearwing damage to these

two poplar trees. We do not formally monitor the distribution of this

species, but records like this are always very interesting and we add

them to our pest & disease database for future reference.

 

Hornet clearwing, Sesia apiformis, is not a primary pest in that it is

not a threat to healthy trees and does not kill trees directly. It isa

secondary pest and only colonises trees that are already stressed orin

decline because of other causes. It is most frequently found onpoplars

that have suffered severe water shortage sometime in the recent past,

i.e. drought conditions in the previous 1-3 years. Once growing

conditions improve most trees usually recover quite quickly and the

numbers of the moth decrease, although their exit holes callous-over

only slowly and may remain visible around the base of the trunk formany

years.

 

Poplar trees that are in permanent decline may support Sesia for much

longer and the attacks by the moth may be one of the combination of

factors that eventually results in the death of the tree. The moth

however, is really only taking advantage of a tree that is already in

decline.

 

It is not known how Sesia selects and finds stressed poplar trees, but

having done so, the female moth scatters her eggs around the base ofthe

tree in an almost random manner and it's up to the newly-hatchedlarvae

to crawl into cracks in the bark and tunnel through to the inner

tissues. The larvae feed on the phloem and cambium tissues between the

bark and sapwood and usually require 2 years to complete their

development. The tunnels can be extensive, but they do not penetrate

deeply into the wood and they do not compromise the structuralintegrity

of the tree. If the tree snaps at the base, it will be because of rot

caused by other factors, which will have been working in the treebefore

the moth arrived.

 

Sesia mainly attacks mature poplars, but it can be found on small and

medium sized trees if these become severely drought stressed.

 

With kind regards,

 

Nigel

 

 

Dr Nigel Straw

Tree Health (Entomology)

Forest Research

Alice Holt Lodge

Farnham

Surrey GU10 4LH

Reception telephone: 01420 22255

Direct telephone: 01420 526232

http://www.forestry.gov.uk/forestresearch

 

 

 

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Edited August 8, 2014 by Al Duffill

[sloth]

Thanks for the update

 

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