What’s eating my rhubarb leaves? :-(

*FlowerGal*

This is my first year growing rhubarb. Up until August I had 2 beautiful healthy vigorous plants... 

Since then all the leaves are getting completely decimated with holes, and turning yellow. I’ve been pulling them out and putting them in the bin. 

Does anyone recognise this issue and know what to do? I’m grateful for any help! :-)

Here’s a few pictures of the sad plants:  

No other plants nearby seem to be affected, except the weed directly behind has similar holes: 



I gave the leaves a good shake to see whether any little creatures fell off but nothing....

I did find a few of these unsightly black splodges but not sure if they are relevant. 

Please help! :-)

Dovefromabove

It’s probably snails .   
Let the leaves die back on the plant do the energy goes back to the crown for next year. 

Fairygirl

I'd agree with @Dovefromabove - most likely slug/snail damage. 
Unfortunately, they're very good at hiding too. It's often the really tiny ones that do the most damage as well.  All you can do is pick them off when you find them - depending on how much time and inclination you have 
It's unsightly, but not detrimental to the plant 

BobTheGardener

As well as slug/snails, it looks like a bit of flea beetle, possibly caterpillar and maybe fungal damage too, none of which you can really do anything about unless you can see the culprits, although keeping the area free of weeds and grass will stop them having somewhere else to hide.  The damage is unsightly but will not really affect the plant.  As Dove says, leave the damaged leaves on the plant to die down naturally as they are doing the vital job of building-up the roots, which store nearly all the food needed for next year's growth.  Few pests attack the stems, which are the bits we want, so unless the leaves are totally eaten away, the crop will come next spring without further action of any kind.