Help with Rhubarb pests (sorry if this isn't a veg)

[Monkey_honk]

Hi there I found these guys on my Rhubarb today I'm a newbie to this so have no clue.

Any help would be appreciated.

Thanks
Amy

[rustylady]

Actually, rhubarb is a veg. No idea what the critters are though, my eyes aren't as good as they used to be and all I can see is little black blobs.