Mis-shapen sloes

[Tursiops2]

Walking along a hedge with a lot of Blackthorn last week, I noticed that many of the Sloes were distorted and mis-shapen. Sorry, no photo; I'll do my best to describe: roughly 4-6 times the size of a normal fruit, mostly tear- or kidney-shaped; pale yellowy green in colour, flushed with darker green. They look like galls, but opening one up reveals a void, empty but for two embryonic seeds, no sign of any insect or larva. On any one bush, I'd say about 50% percent were like this, the remainder of the fruit being normal.

I've never seen this before. Anybody know the cause?
T2

[poschiavanus]

These are galls caused by a fungus Taphrina pruni, and are known as 'pocket plums'. Here's a recent picture on WAB:

[Tursiops2]

Ah, so it is a gall. That's interesting, thank you. As I say, I've not seen it before, would you know if it's a frequent occurrence?
T2

[poschiavanus]

An interesting question!

There are only 175 records in the Fungal Database of the British Isles, but I think like many fungal plant parasites it is under-recorded.

So far this year I've found it on Blackthorn where I've looked for it, but today's finds required a couple of minutes to find one or two mouldy sloes. Last week I found a hedgerow which was absolutely full of them.

In my experience it is commoner on the garden Cherry Plum, and pretty easy to see on both the green leaved and dark red leaved varieties ('Pissardi'), but there are only about 30 formal records on this host.

I also have the impression that the pocket plums don't last that long, and once the main crop of true plums and sloes is reasonably advanced they're much harder to find.

I would think that there is an english name shows that it was/is a well known phenomenon to gardeners and, possibly, makers of sloe gin.

posch

[Tiggrx]

I see occasional specimens most years (last weekend for example in Somerset), but only ever on Sloe or Plum. Despite there being a lot of Cherry Plum around I have never seen it on this host.