I see some leaf damage on mine, but not a lot of chewing. Some of the old leaves turn brown and die, but they're still putting up new ones. I gave them all some chicken poop compost, and they got a lot of new growth after that.
My rhubarb history:
A neighbor gave me a split off one of hers. It's now huge and healthy. The next year (2023), I bought two plants. One did well; about August of last year, the other one looked like it was dying.
I read online about crown rot, assumed that's what the problem was, and dug it out. I *thought* there *might* be some mushiness to the root, but wasn't sure. That plant came back this spring -- tenacious, and I didn't get the entire root, obviously -- and I apologized to it profusely, claimed ignorance, gave it extra compost, and it's hanging in there.
Crown rot seemed to be the major problem rhubarb might have, other than something eating the leaves. I don't see a lot of bugs on my plants.
The rest of the saga...
This spring, I bought 3 crowns from a nursery. They were dried up and shriveled and about $50 for the three. Only one made it, and it is growing well. But... It's supposed to be the variety Canadian Red, and all of the stalks are green, like the variety Victoria. I really hope the stalks are red next spring and that the greenness is a juvenile plant phase it's going through. If not, I won't be buying plants from that store again. This isn't the first time I've gotten less than/not what I paid for.
Guarantee be damned; I'm not going to argue about the money. They can't do anything about me losing a year.