I have recently become very interested in plant pathogens. Here I will document the different species I see in Ireland, organised by month. I hope this site will be a useful resource, both as a reference and to inspire people to take notice of these underappreciated organisms. They are incredibly diverse in form and ecology, and are so ubiquitous that they cannot be ignored. I originally was only recording fungi and oomycetes but have since expanded to all gall-forming organisms.
30th March 2024
Ramularia septata on
Galanthus cf. nivalis
from Orangefield Park.
9th-10th April 2024
Mycosphaerellaceae sp. on
Escallonia sp.
in North Down.
Note both Septoria escalloniae and Mycosphaerella escalloniae
are known from this host, and can only be distinguished microscopically (I'll get round to it eventually...).
12th April 2024
Albugo leimonios on
Cardamine pratensis
in Clement Wilson Park in the Lagan Valley.
12th April 2024
Entyloma fumariae on
Fumaria sp.
in the Lagan Valley.
21st April 2024
Urocystis primulae on
Primula vulgaris
at Killard Point.
Note the white conidia around the anthers and the black spore mass in the ovary.
30th June 2024
Peronospora fulva on
Lathyrus pratensis
in Moreland's Meadow, Lagan Valley.
2nd July 2024
Septoria anthyllidicola on
Anthyllis vulneraria
in our garden in East Belfast.
Note the small, dark pycnidia (fruiting bodies in the leaf tissue) which have burst open to release conidia.
This species has not been previously recorded in Britain or Ireland, so it was a particularly exciting find.
Septoria has recently been discovered to be far less host-specific than previously thought (Verkley et al., 2013)
so it may be lumped into another species.
9th-10th July 2024
Pucciniastrum on
Soleirolia soleirolii
in Acaill, Mayo. This taxon was discovered by Chris Preston in Cambridgeshire.
Its identity is unknown - see
Preston, C. D., Harries, D. J., & Stringer, R. N. (2023). A newly discovered rust on Soleirolia soleirolii. Field Mycology, 24(1), 13–17.
10th July 2024
Pucciniastrum guttatum on
Sherardia arvensis
in an Caol, Acaill, Mayo.
10th July 2024
Entyloma on
Ranunculus baudotii
in an Caol, Acaill, Mayo.
This is an undescribed Entyloma species in the Entyloma eburneum complex.
This group has not been recorded on R. baudotii before so it may be new to science,
or it could be the same species as infects other Water Crowfoots. The species on Crowfoots
haven't been studied yet so its taxonomy remains unclear.
11th July 2024
Septoria on
Bellis perennis
in Bun an Churraigh, Acaill, Mayo.
There are two species of Septoria on Bellis perennis according to Unamuno (1942):
15th July 2024
Peronospora sparsa on
Rubus fruticosus agg.
in Tyrone.
Note some authors consider Peronospora on Rubus to be a separate species (P. rubi).
20th July 2024
Puccinia asperulae-odoratae on
Galium odoratum
in Black Mountain, Belfast.
This is often considered a junior synonym of the widespread P. punctata which has been found in Ireland previously.
22nd July 2024
Sphaceloma symphoricarpi on
Symphoricarpos albus
in Tyanee, Derry.
The pycnidia are very small, pale brown, and inconspicuous! Thanks to Matthew Rogers for ID.
25th July 2024
Septoria posoniensis on
Chrysosplenium oppositifolium
in Cregagh Glen.
There are only three previous records on this host, but the spore size matches the description from other Chrysosplenium species.
26th July 2024
Erysiphe akebiae on
Akebia quinata
in Botanic Gardens, Belfast.
This is probably a recent introduction as there are no British records before 2002.
28th July 2024
Leptosphaerulina myrtillina on
Vaccinium myrtillus
in Cottage Farm, Tyrone.
This one is definitely extremely common - I remember seeing it in the Mournes before.
1st August 2024
Claviceps humidiphila on
Dactylis glomerata
in Belvoir, Lagan Valley. This was recently split from C. purpurea sensu stricto and can be distinguished as it floats in water. Some of the previous Irish records of that species are certainly this one.
1st August 2024
Sphaerulina gei on
Geum urbanum
in Belvoir, Lagan Valley.
7th August 2024
Ramularia episphaeria (=Phacellium episphaerium) on
Stellaria palustris
near Banbridge, Armagh.
16th August 2024
Podosphaera phtheirospermi on
Euphrasia sp.
at Killard Point NNR, Down.
16th August 2024
Entyloma matricariae on
Tripleurospermum maritimum
at Killard Point NNR, Down.
27th August and 13th September 2024
Cecidophyopsis atrichus on
Rabalera holostea (left) and Stellaria graminea (right)
in Down.
This mite seems to be rather underrecorded.
3rd September 2024
Dasineura "B" sensu Harris on
Filipendula ulmaria
in Derry.
An undescribed Dasineura gall midge. It is apparently common in Britain. Thanks to sk53 on iNaturalist for ID.
8th September 2024
Contarinia dipsacearum on
Succisa pratensis
at Murlough NNR, Down.
One or several larvae sit at the base of an unopened flower. The tell-tale sign is
that galled flowers are surrounded by open flowers, as if they should also be open.
There is only a single other record for this species from Ireland or Britain,
from London in 1947. It may turn out to be genuinely rare, though the subtle
symptoms means these flower-galling Dasineura are easily overlooked.
13th September 2024
Subanguina graminophila on
Agrostis stolonifera
at Lagan Meadows, Belfast.
A nematode gall. There are very few global records but it is probably extremely underrecorded.
Within a week I found it at two other sites so it is probably widespread and common in Ireland.
16th September 2024
Bremia taraxaci on
Taraxacum agg.
in South Armagh.
20th September 2024
Peronospora trifolii-repentis on
Trifolium repens
in Ballymorran.
This one appears to be genuinely rare. I had been looking for it fairly intensively all year!
Then again the symptoms are very subtle and probably easily overlooked, even when searching for it.