And how to I treat this?
Could it be slugs? I'm having a terrible problem with slugs. I put down a product from the hardware store for slugs and it seems to help.
The holes look to me like insect eggs from underneath the leaves have hatched and got their first meal from the leaves they were hidden under. One treatment is to add a little dishwashing liquid to a quart of warm water, in a spray bottle. Spray the underside of every leaf and wipe it with a clean rag, then was the topside of every leaf. If you have liquid left over, label the bottle and add warm water when you are ready to use it again. Best wishes! Jewell
Take a leaf to a local nursery.
It may be slug damage. Crush up some egg shells and place around the base of the plants and they will not cross. Slug bait works really well too. Just sprinkle a bit around the base of the plant.
I generously sprinkle diatomaceous earth around the base of my hostas and a little on the leaves. Keeps slugs at bay.
I agree that the damage looks like slug damage. I tried crushed up egg shells for my slug problem and they didn't really work. I use a product in the spring call Sluggo around the base of my hosta and other plants that the slugs eat. If I repeat the product again in the middle of summer, I have minimal slug damage. Good luck and happy gardening!
7dust works well, not harmful to pets. You can buy it at any hardware store, Walmart etc.
It’s not slugs but some type of worm. I have pulled them off my canna plants. I had great success with 7 dust. The little buggers will eat the flowers too before they even bloom.