nurtomiChewed leaves and caterpillars
Holes can have several causes; look for the visitor.
What to look for
Inspect leaf edges, undersides and nearby stems for caterpillars or fresh droppings. Old holes cannot tell you what caused them, and some insects may already have left.
What to do
If you find caterpillars on a plant you want to protect, remove them by hand when practical. Check again for fresh damage and avoid treating the plant solely for old holes.