Young box hedge moth caterpillars rasp green tissue from leaf undersides so the leaves appear peeled. Older larvae skeletonize entire leaves. Persistent feeding weakens box, causes unsightly brown patches, and may kill weak plants.
Carefully inspect new box hedging before planting them, because this pest has secretly spread in nurseries. As a safety precaution, treat new box with a Bacillus thruingiensis-based organic pesticide if any leaves show feeding damage.
Wrap the end of a stick with outward-facing tape and use it to loosen and gather actively feeding caterpillars by swirling up webbing with the sticky end. Immediately treat plants with an organic pesticide with Bacillus thuringiensis or Spinosad as its active ingredient, taking care to cover leaf undersides. Repeat after 10 days to kill small larvae that may have hatched.