Chirosia grossicauda

This small fist-like ball on the end of this fern frond is caused by a fly called Chirosia grossicauda. The larvae tunnel into the central veins of the pinnules in late summer and cause them to roll downwards from the tip. The solitary white maggot feeds on the main vein by mining. Mature larvae most... Continue Reading →

About Plant Galls

I have always been fascinated by these strange yet sometimes most beautiful growths. Plant galls are something of an oddity when some folk first encounter them, others don’t even know they exist. Plant galls come in all shapes and sizes, and are formed by another organism using the plant as a host, using it for... Continue Reading →

Aceria myriadeum

A tiny mite produces the pimple-like spots on the leaves of Field Maple (Acer campestre). Each pustule measuring between 1-3mm high may contain several mites. The galls maybe fairly prolific, covering leaves almost in their entirety. The mites leave the gall through tiny holes in the underside of the leaf in autumn and overwinter in fissures... Continue Reading →

Eriophyes laevis

This is a mite which produces tiny red pustule galls on the upper surface of Common Alder (Alnus glutinosa). They are up to 2mm in diameter, and are green to begin with, becoming red or purple later on. They may cover the whole upper surface of the leaf, and in some cases this may prohibit growth... Continue Reading →

Sycamore Felt Gall

Aceria pseudoplatani This is a mite which produces felt-like galls on the surface of Sycamore (Acer pseudoplatanus) tree leaves. On the top side of the leaf the gall is like a blister which is usually yellowish to begin which then turns brown, and underside it is cream or yellowish when fresh, browning as it ages. The... Continue Reading →

Cherry Gall Wasp

Cynips quercusfolii These marble like galls measuring up to 25mm in diameter are found beneath the leaves of Pedunculate Oak (Quercus robur) and Sessile Oak (Quercus petraea). Cynips quercusfolii is a tiny black gall wasp, and within the plant gall its larva stage grows. On Pedunculate Oak the gall is smooth where on Sessile Oak it... Continue Reading →

Robin’s Pincushion

Diplolepis rosae This strange yet beautiful growth is the result of a tiny gall wasp called Diplolepis rosae laying its eggs in a wild rose bud in springtime. Also called the 'Bedeguar Gall Wasp', the females appear in the spring just in time to lay their eggs in the fresh young buds. Males are a... Continue Reading →

Aceria macrorhynchus

This is a mite which produces tiny red pustule galls on the upper surface of Sycamore (Acer pseudoplatanus) tree leaves. They grow up to 6mm high. The females overwinter in crevices in the bark of the Sycamore tree, emerging in spring to feed on the new leaves, which is what causes the red raised spots. On... Continue Reading →

Knopper Gall

Andricus quercuscalicis Whilst on a walk through a local churchyard I noticed these fine old Turkey Oaks (Quercus cerris) in the grounds. I saw all these strange knobby growths on the acorns. I took these series of photographs, and although I knew they were a plant gall of some kind, I later identified them as the... Continue Reading →

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