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The Society for the study of flies (Diptera)

Affiliated to the British Entomological and Natural History Society (BENHS)

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#1 2008-08-28 23:30:25

jaapiella
Registered user
Name: Scotty Dodd
From: Surrey/Hants border
Registered: 2008-06-27
Posts: 64

Records of Jaapiella genisticola

Dear all

I wondered if any members had records of the gall inducing midge Jaapiella genisticola on the plant Genista tinctoria (dyers greenweed). I would particularly welcome records from Surrey VC17.

A site manager recently passed me this gall from an area where it has apparently not been recorded for at least 20 years. The identification has been confirmed by Keith Harris, an expert in the Cecidomyiidae, who has been extremely helpfull in various aspects of this investigation.

Incidentally, I am currently the plant gall recorder for VC17 and I would also welcome any records members might have for dipteran gall causers. We anticipate a checklist for the county in the future along with an illustrated atlas for gall causers on oak.

Please email jaapiella@yahoo.co.uk - mapmate excell format preffered but anything accepted, even records on the back of envelopes... All records will be sent to the national plant gall database on you behalf.

Regards

Scotty

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#2 2008-08-30 01:05:17

jaapiella
Registered user
Name: Scotty Dodd
From: Surrey/Hants border
Registered: 2008-06-27
Posts: 64

Re: Records of Jaapiella genisticola

Hello all

I thought that it might be of use to summarise my provisional notes on the appropriate management for Jaapiella genisticola within a grazing regime based upon discussions with an expert in the life cycles of the Cecidomyiidae (gall midges) and a Wildlife Trust site manager.

The eggs/larvae of J.genisticola causes 'artichoke' type galls at the shoot tips of Dyer's Green-weed Genista tinctoria during the summer months. Clearly grazing at the wrong time of year might affect populations of what appears to be a  localised fly.

At the site in question low level cattle grazing begins in early March and ends in early May. After the cessation of grazing G.tinctoria, which is usually browsed, puts out fairly vigorous new growth (O'Hara, pers. com.). It is this new growth which is usually galled.

The site is again grazed in October. By this time the larvae of Jappiella have migrated to the soil layer (Harris, pers. com.) and are not affected by browsing.

Conclusion: Summer grazing (i.e. June - Aug) of sites supporting Jaapiella genisticola may be detrimental. Equally, non-intervention management is likely to lead to plant succession and the eventual loss of the host plant. Overgrazing is also likely to be detrimental.

If anyone has any other experiences of management that is benficial or detrimental to the host plant or gall inducer I would be glad to here of it.

Thanks

Scotty

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