I have a number of potted geraniums on my porch, on the floor and on the railing. They always seemed easy to keep healthy but in the last week while we were away, they are being eaten one by one by some strange pest.

They eat big holes in the leaves, leave little black specks everywhere and I found a few little green caterpillars about an inch long wrapped up in some of the leaves with webbing... rather cute, but I do not appreciate them eating my flowers. My partner has many allergies and he is deathly sensitive to pesticides with a multiple chemical condition. Over the years with other unsuccessful attempts at porch gardening I settled upon geraniums because they seemed to thrive and resist aphids and did not have to be sprayed, but I am so upset. I broke off all the branches that seemed to be infected, leaving little behind, and completely eliminated the chewed up primroses (which had also been attacked, but I was not attached to them anyhow) but the pests have now moved from the porch to the geraniums on the railing. There is only one hanging basket with my favourite candy-striped geranium that seems for now unaffected. Is there a non-poisonous way to control these creatures? What are they? I am not very familiar with plants, as you can tell/ I tried looking up these little worms on line and had no luck. Thank you.