Answer: Erigeron does not play host to too many insect pests so I wonder if slugs or snails are feeding on your plants? Look for silvery slime trails on and around the plants and bait or trap them if you find them in your garden. Aside from these critters, sometimes caterpillars will feast on flowers and then leave the area. You can carefully inspect the entire plant, especially the undersides of leaves for small green caterpillars. If you find some, the botanical Bt (Bacillus thuringensis) is effective against them.
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