Re: Elm leaf galls

by Howard Matcham :: Rate this Message:

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Hi Sarah,

Many thanks for sending your excellent photograph. I've not yet seen the galls on figwort but will look out for it.

Have you noticed that vast populations of the nettle aphid Microlophium carnosum have been decimated by the fungus Pandora neoaphidis and the underside of nettle leaves are smothered with the yellow cadavers? I've sent material to RBGK at the request of Brian Spooner, head of mycology, just to make absolutely sure the fungus is not a new or introduced species.

Howard

H.W.Matcham

Managing Editor, Journal of Bryology.
E-mail: hwlgmatch@...
Tel.: 01243 781238 +44 (0)1243 781238
21 Temple Bar, Strettington, Chichester, West Sussex. PO18 0LB U.K.

From: "house.mouse@..." <house.mouse@...>
To: Adastra discussion group <adastra@...>
Sent: Saturday, 27 June, 2009 12:42:30
Subject: Re: [Adastra] Elm leaf galls

Hi Howard

Some very interesting finds.

I have only seen Eriosoma lanuginosum once, and that was at Portland in Dorset, It is an amazing (and relatively huge!) gall. I have a photograph of the specimen at

http://farm2.static.flickr.com/1057/697782517_ded4cb72f6.jpg

it was about 10cm across.

I have noticed recently a large number of Common Figwort plants with galled flowers. These galls are caused by the midge Contarinia scrophulariae.

http://farm4.static.flickr.com/3645/3664377561_ef8945e82d.jpg

Sarah

From: Howard Matcham <hwlgmatch@...>
Subject: [Adastra] Elm leaf galls
To: "Adastra discussion group" <adastra@...>
Date: Saturday, 27 June, 2009, 12:14 PM

Dear All,

I have recently found two interesting gall species on elm (Ulmus procera) leaves in the Strettington/Boxgrove area.

Eriosoma lanuginosum is a relatively large gall and the Strettington specimens (two) measure 4cm in diameter. Aphids left the first gall which splits at the side and apex to release aphids on the 19th and the second gall on the 22nd of this month (June). Looking into the gall with a x20 handlens I was surprised to find many globular balls of wax which aphids were feeding on. Does the elm produce the wax or an aphid generation?

Tetraneura ulmi according to the FSC British Plant Galls, is locally common and I have only seen it previously on a Small-leaved elm (U. minor) in Burgess Hill churchyard. Elms in the Strettington/Boxgrove area are smothered with this species and I would be very interested in other sightings. The gall is balloon shaped and up to 1.5cm high, it is very distinctive in that the leaf is discoloured a bright yellow and easy to spot.

Elm suckers in the Chichester area are frequent and survive for between 10-15 years before succumbing to 'Dutch Elm' although they do regenerate from suckering.. Elm hedge that are frequently trimmed do not seem to succumb to the disease.

The leaf gall Hayhurstia atriplicis; Hemiptera: Aphididae, is found on Atriplex sp. (Orache) and a field at Boxgrove planted with Field Beans has a ground flora of Atriplex patula (Common Orache) with hundreds of leaves galled. Has anybody seen this gall in quantity this year?

Best wishes,

Howard

H.W.Matcham

Managing Editor, Journal of Bryology.
E-mail: hwlgmatch@...
Tel.: 01243 781238 +44 (0)1243 781238
21 Temple Bar, Strettington, Chichester, West Sussex. PO18 0LB U.K.

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