The borer is a caterpillar in the same family as the corn earworm and cabbage looper. Eggs - The eggs are almost spherical and are creamy with a greenish tinge to pale purple. The eggs are about 0.5 mm in diameter. They grow to almost 3.5 cm long. Pupa - The pupae are about 3 cm long and 6 mm wide.
Pupae are reddish brown to dark brown.
85 Iris borer. B, Male moth. Host Plants - iris borer apparently feeds on Japanese, German, and blueflag irises. Damage - The tiny caterpillars first feed on the new foliage and sometimes cause the margins of the leaves to bleed sap and be ragged. Narrow, water soaked slits appear where the external feeding and mining have injured the leaves.