Answer: Without seeing and identifying the pest, I can't recommend a control - not all treatments are effective against all pests. If you don't see any insects, the damage was caused by some chewing pests who feasted on the foliage and then left the plant. Carefully inspect your plant (especially the undersides of the leaves) for insect activity. If you find the culprits, take a sample to your local nursery or Cooperative Extension office for identification and control measures.
Best wishes with your garden!
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