What's eating my kai-lan (gai lan)?

Kai-lan (Gai Lan) is a robust brassica but still falls prey to flea beetles on seedlings, cabbage white caterpillars devouring the thick, blue-green leaves, aphids colonising the edible flowering stems, and diamondback moth larvae, which are a significant pest in warmer regions. Caterpillars are the most consistently damaging threat to mature plants.

Cabbage whites cut large irregular holes; diamondback moth larvae create characteristic windowing (eating leaf tissue while leaving the upper skin intact); both produce frass on leaves and stems. Exclusion netting is the primary defence; Btk spray targeting young larvae; hand-pick egg clusters from undersides; diamondback moth quickly develops insecticide resistance — rely on Btk and netting, not synthetic sprays.

Shot-hole damage on seedlings and young transplants; thicker kai-lan leaves are more tolerant once mature but seedlings can be set back significantly. Row cover or mesh from sowing; delay transplanting; keep well watered.

Colonies on flower buds and stems; waxy grey coating; distorted flowering shoots — the part most commonly eaten. Check stems twice weekly; insecticidal soap spray directly on colonies; harvest promptly; avoid excess nitrogen.

Holes in outer leaves and slime trails, especially on young plants and after rain. Iron phosphate pellets; beer traps; hand collection at dusk; grit mulch around stems.