Cabbage Webworm (Hellula undalis) – Brief Overview

Identification & Distribution

• Belongs to the Crambidae family.
• Found across Europe, Asia, and the Pacific; common in tropical and subtropical regions.
• Wingspan: ~18 mm.
• Adult moth: Pale greyish-brown with grey wavy lines and a pale apical spot on forewings.

Life Cycle

• Egg stage:
  • Oval, laid singly or in clusters on leaf undersides.
  • Initially pearly white, turning pink, then brown.
  • Hatches in 2-3 days.
• Larva stage:
  • Pale whitish-brown with 4-5 purplish-brown stripes.
  • Feeds on leaves, stems, and the plant’s core.
  • Larval period: 7-17 days.
• Pupa stage:
  • Forms a cocoon.
  • Lasts 6 days.
• Adult stage:
  • Pale greyish-brown moth with distinct wing markings.
  • Completes life cycle in 15-25 days.

Damage & Impact

• Young larvae mine leaves and bore into stems.
• They penetrate the plant’s core, preventing head formation.
• Infestation leads to wilting and frass exudation.
• Spins silken tubes while feeding.
• Affects cruciferous crops, often co-occurring with diamondback moth (Plutella xylostella).

Control Challenges

• H. undalis and P. xylostella infestations overlap, complicating pest management.
• Control measures for P. xylostella may negatively impact H. undalis' natural enemies.