Worcestershire Record No. 17 November 2004 p. 54

SOME OBSERVATIONS ON WORCESTERSHIRE GALLS

J.J.Day

I have been recording plant galls, on a casual basis, since the mid-1980s. Over the past few years I have adopted a more systematic approach, attempting to record all those I see.

In August 2004, I ran out of WBRC recording slips and resorted to entering all my records on an Excel spreadsheet. As the recording season draws to a close, it struck me on looking down the table, that there may be some useful comparative data in my records.

The following results are based on my observations August 2004 to November 2004.

Field Maple, Acer campestre

There are two common gall-causing eriophyid mites. These form small reddish pustules or pimples on the upper surface of the leaf - Aceria aceriscampestris forms abundant small red pimples, Aceria macrochelus tends to occur in much smaller numbers and forms larger blunter brownish-red galls

I have 31 records from 34 sites

Aceria aceriscampestris

12

35%

Aceria macrochelus

29

85%

Pedunculate Oak, Quercus robur

Oaks have a diverse associated fauna, including gall formers. Prominent amongst the latter are Cynipid Wasps. All my observations, as tabulated below, belong to this group.

I have 96 records from 55 sites

Andricus corruptrix

 

2

3.5%

Andricus curvator

 

4

7%

Andricus fecundator

Artichoke Gall

6

11%

Andricus kollari

Marble Gall

7

13%

Andricus lignicola

Cola-nut Gall

2

3.5%

Andricus quercuscalicis

 

12

22%

Biorhiza pallida

Oak Apple

3

5%

Cynips divisa

Pea Gall

2

3.5%

Neuroterus anthracinus

Oyster Gall

1

2%

Neuroterus numismalis

Silk Button Gall

9

16%

Neuroterus quercusbaccarum

Common Spangle Gall

46

84%

Neuroterus quercusbaccarum

Currant Gall

2

3.5%

Alder, Alnus glutinosa

There are three British species of mites which form galls on Alder leaves.

I have 21 records from 18 sites

Acalitus brevitarsus

3

17%

Eriophyes inangulis

4

22%

Eriophyes laevis

14

78%

Editorís note

There is a new and excellent set of keys to galls:

REDFERN M, SHIRLEY P & BLOXHAM M 2002 British plant galls. Identification of galls on plants and fungi. Field Studies Council, Preston Montford. AIDGAP key

 
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