I have been growing Rocket and Charlotte potatoes in a deep multch of very old horse manure from sawdust pellets and composted conifer hedge clippings. I dug some up yesterday as I thought the leaves looked blighted and collapsed (even though I sprayed with bordeaux mixture and something French to kill the colorado beetles. I also have some Sarpo Blue Danube that have not been hit by the early blight (if that is what it was! not surprising with the MASSIVE amount of rain we have had here)
Several have been half eaten, the teeth marks don't show up well but look quite small and sharp..., they were well burried so I think whatever munched them could be underground? We have had rats in the tunnel in the past and I am forever blowing up moles! that bed did have a toad in it last year. Also some of the spuds had tiny white raised dots which rubbed off and has turned browner overnight before I took the pics.

Any ideas potato experts?

I know about potatoes, but I'm not familiar with the rodents in your part of the world. These are for sure the teeth marks of some beast, more than likely rats. But since I don't know what else marauds around your neighbourhood it's hard to narrow it down.

Unless you can be sure that what's been ailing your potatoes is blight, I can't see any purpose in applying a fungicide. Also, whatever you apply does not work after the event: blight can only be prevented, not cured. Are you sure the haulms hadn't just started dying down naturally? Rocket, in particular, has a very short lifespan. Looking at the spuds in your photo, they seem to be fully developed.

Interesting re the blight, it certainly looks like blight and all the tomatoes have got it too even in the tunnel. I spray every year before it gets going but I guess that all the rain is washing it off outdoors as soon as I put it on! I don't normally grow many earlies and prefer the Sarpo blight free range as they always do so well here without needing any spraying (except once for the colorado beetle)so yes, the rocket especially has died down more than the Charlotte you could be right about that.

Critters? we had rats, there were also Coypue (sp?) near the lake last year. The cats catch various voles and mice and I once found a dead stoat/weazel. Thats about it for wildlife around here apart from wild boar and deer. Never seen a fox or squirrel, badger. all around us are huge flat fields of Rape, sunflowers and feed maize, hardly any hedges or cover. We have two dogs, good at chasing anything big away. a large black lab/beucheron cross and a little Pyrenean Sheepdog Ella who has quite a terrier like determination to dig up moles, mice etc although she has never eaten a mole.

I better go and find the rat poison and bait station.......

EDIT I just found on Google that voles can make that kind of teeth marks and often eat potatoes underground.

Does anyone know how to trap/poison a vole? my cats don't go as far as the veg garden, they prefer the easy win of mice and spiders in the old attic!

As my digging skills are somewhat limited by various issues I took Ella out between thunder storms this afternoon for a bit of digging...
Once she understood what she was digging for she did a good job. (The breed nearly died out during WW2 as they are so bright and learn quickly, they were used by the Resistance and Army) the entire bed was tunnelled, Ella had a great time! so for the benefit of others who may find this thread. I had created an ideal enviroment for voles, thick multch, no cultivation because I can't dig/hoe/earth up etc. The voles have eaten almost all the Rocket but didn't appear to like the Charlotte or the Blue Danube.

Tomorrow I will get long suffering Mr D to Mantis the entire bed.