Gall of the week is that caused by the gall midge Rabdophaga salicis on willows, Salix spp. Photo by Peter Shirley.

Gall of the week is caused by a recently discovered species new to Britain, the gall wasp Andricus coriarius f. agamic on oak, Quercus robur. Discovered and photographed by Maria Fremlin.

Gall of the week is caused by the cynipid wasp Andricus quercuscorticis f. agamic on oaks, Quercus spp. Photos by Graham Callow.

Gall of the week, with its causer, is that of the tephritid (picture wing) fly Urophora cardui on thistles Cirsium spp. Brilliant photo of the insect by Malcolm Storey, gall photo unknown source.

Gall of the week, with a bonus small copper butterfly, is caused by the midge Dasineura kiefferiana on rosebay willowherb, Chamerion angustifolium. Photo by Mike Poulton.

Gall of the week, can be found all year round, is caused by the gall midge Taxomyia taxi on yew, Taxus baccata. This is the second year gall, more often found than its smaller counterpart, the one year gall. Photographer unknown.

Gall of the week is that of the midge Contarinia nicolayi on hogweed, Heracleum sphondylium. With a name like that perhaps we should call it Santa's gall. Photo by Peter Shirley Thanks for following, best wishes and good galling in 2026.

Gall of the week is one you may be bringing into your home this week. It is the gall of the aphid Sacciphantes viridis on Norway spruce, Picea abies. Photographer unknown.

Gall of the week is that of the cynipid wasp Aylax papaver on poppies, Papaver spp. An ungalled seedhead is included. Photo by Peter Shirley

Gall of the week is caused by the cynipid wasp Cynips longiventris f. agamic on oaks, Quercus spp. Photo by Peter Shirley

Gall of the week is caused by the gall midge Iteomyia capreae on willows, Salix spp. Photographer Peter Shirley.

Gall of the week is that of the sawfly Blennocampa phyllocolpa on roses Rosa spp. Photo by Tom Higginbottom on Bladmineerders.nl

Gall of the week is the nail gall of the mite Eriophyes tiliae on lime trees Tilia spp. Photo by Mike Poulton.

Gall of the week, usually found in leaf axil buds, is caused by the cynipid Andricus glandulae f. agamic. On oaks, Quercus spp. Photo by Peter Shirley

Gall of the week is that of the curiously two-chambered one of the cynipid wasp Cynips disticha f. agamic on oaks, Quercus spp. Photos by Malcolm Storey.

Gall of the week is caused by the fungus Taphrina tosquinetii on alder, Alnus glutinosa. Photographer unknown.

Still in Ohio, gall of the week is a leaf gall on white swamp oak, Quercus bicolor. Seems to be Neuroterus quercusverrucarum, the oak flake gall. Is this correct @gallformers? Photo by Peter Shirley.

Gall of the week: Galling is in Ohio USA, and came across this. Seems to be a rough oak bulletgall caused by the cynipid wasp Disholcaspis quercusmamma on swamp white oak, Quercus bicolor. Happy to be corrected. Photo by Peter Shirley.

Gall of the week is that of the cynipid wasp Aulacidea follioti on prickly sow thistle. Sonchus asper. Photos by Jean-Yves Baugnee from Plant Parasites of Europe Bladmineeders.nl

Members of the BPGS enjoying our annual gall weekend in Yorkshire last Saturday and Sunday.

Gall of the week is caused by a moth, Mompha sturnipennella on rosebay willowherb, Chamerion angustifolia. Gall photo by Tom Higginbottom, causer photo unknown, taken from the British Plant Gall Society website: www.britishplantgallsociety.org

Just discovered a rare newspaper article on a gall - that of Diplolepis rosae, robin's pin-cushion. It’s the Guardian's Country Diary today, by Kate Blincoe. Find it at theguardian.com

Gall of the week is caused by a gall midge, Dasineura hyperici on Hypericum spp. St. John's- Wort. Photographer not known.

Gall of the week is the little gem caused by the cynipid Neuroterus anthracinus f. agamic on oaks Quercus spp. For some strange reason known as the oyster gall. Photographer unknown.

Don't forget folks iNaturalist's Gall Week is coming up - it's from the 6th to 14th of this month.

Gall of the week, maybe gall of the year it seems to be super-abundant just now, is that of the cynipid wasp Neuroterus numismalis f. agamic on oaks Quercus spp. Photo by Peter Shirley.

Gall of (last) week which somehow disappeared into the great digital universe in the sky, is caused by the cynipid wasp Trigonaspis f. agamic on oaks Quercus spp. Photo by Peter Shirley.

Gall of the week, one that maybe needs a bit of searching for, is a caused by avgall midge, Asphondylia ononidis, on restharrow, Ononis repans. Photos by Sue Timms.

Gall of the week is that caused by the aphid Hayhurstia atriplicis on oraches Atriplex spp. Photo by Roelef Jan Koops.

Gall of the week is the fungal gall of Claviceps purpurea otherwise known as ergot, on many grasses and cereals. It is the cause of St. Anthony's fire mania if consumed in contaminated flour. Photographer unknown.

Gall of the week is a bit of a mystery. It occurs on tree-fuschia, Halleria lucida, in South Africa, I suspect it is caused by a cynipid wasp, Halleriaphagus phagolucida, but does anyone know different? Photo by Peter Shirley

Test

Gall of the week, well two actually. A chimera with the cynipid galls of Andricus kollari/infectorius f. agamic agg and A. aries f. agamic growing in close proximity on oak Quercus spp. Photographer unknown.

Have been catching up with verifying cynipid galls on iNaturalist. The process can be greatly speeded up if you can remember to add the generation to the name. For example Biorhiza pallida f. sexual for the oak apple gall causer, and Andricus aries f. agamic for the ramshorn gall causers.

Gall of the week is a fungal gall which at first sight might be taken for an invertebrate gall, although the there is a larger protuberance on the underside of the leaf. It is caused by Exobasidium vaccinii on cowberry, Vaccinium vitis-idaea. Photo by Mike Poulton.

Gall of the week is caused by the midge Jaapiella veronicae on speedwells, Veronica spp. According to Skuhrava and Skuhravy in 'The Gall Midges of Europe' this is the commonest gall midge in Europe. Photographer unknown.

Gall causer rather than gall of the week this time. A sexual generation female of the cynipid wasp Trigonaspis megaptera which causes galls on oak trees, Quercus spp. Photo by Michael Chinery.

Gall of the week is caused by the psyllid Trichochermes walkeri on buckthorn, Rhamnus carthatica. Once vacated by the causer the gall is often home to aphids. Photo by Graham Calow.

Gall of the week is I think that of the scale insect Pachypsylla celtisdismamma on hackberry, Celtis occidentalis, in North America. Photo by Peter Shirley.

#galls Welcome and thank you to all our new followers, please spread the word. Here is this week's gall of the week, specially for any new North American friends, it is caused by the cynipid wasp Diplolepis triforma on the rose Rosa acicularis. Photo from Sudbury Ontario by Peter Shirley.

Gall of the week is caused by the weevil Rhinusa antirrhini on common toadflax, Linaria vulgaris. Photographer unknown.

Gall of the week, found in @galling's garden this week, is the sexual generation currant gall of the cynipid wasp Neuroterus quercusbaccarum on oak Quercus sp. Photo by Peter Shirley.

Gall of the week is caused by the mite Eriophyes exilis on Tilia cordata, small-leaved lime. Also occurs on other limes. Photos by Graham Callow.

Gall of the week is unusual looking mistletoe, Viscum album. It's host tree has died so it has changed to autumn colours!

Gall of the week, easy to find now, is caused by the mite Phyllocoptes goniothorax on hawthorn, Crataegus monogyna. Photo by Tom Higginbottom.

Gall of the week is back with the gall caused by the gall midge Putoniella pruni on Prunus spp. especially blackthorn P. spinosa. Photographer unknown, please say if it is you.

Gall of the week, coming to an oak tree near you soon, oak apples, caused by the cynipid wasp Biorhiza pallida. And a reminder that Oak Apple Day is May 29th. Photograph by Mike Poulton.

Gall of the week still, easy to spot before the leaves appear, is the cynipid caused gall of Andricus curvator agamic generation on oaks, Quercus spp. Photo by Jenny Seawright.

Gall of the week is caused by the Agromyzid fly Hexomyza simplicoides on various willows, Salix spp. Photos by Volker Fasner and Jean-Yves Baugnee from Bladmineerders website.

Gall of the week, appearing now, is caused by the fungus Uromyces ficariae on lesser celandine Ficaria vernus. Photographer unknown.