Cabbage White Butterfly UK
Cabbage white caterpillars can strip brassica plants to bare stems in days. Netting is the only truly reliable defence.
Pest control advice verified against RHS guidance by the SoilCommander Growing Team.
Two Species
The UK has two cabbage white species. The Large White (Pieris brassicae) lays clusters of yellow eggs on leaf undersides; its gregarious caterpillars feed in groups and do severe damage. The Small White (Pieris rapae) lays single eggs; solitary green caterpillars are harder to spot and can be more damaging overall.
Peak Season
Adults are active from April to October with peak egg-laying in two main waves: late spring (May–June) and late summer (August–September). The second generation in August is typically the most damaging.
Control Methods
- Fine mesh netting (1.3mm or finer): the only fully reliable prevention; fit immediately after transplanting and keep in place April–October
- Inspect weekly: check leaf undersides for egg clusters and caterpillars; remove by hand
- Companion planting: nasturtiums act as a trap crop, attracting egg-laying away from brassicas
- Biological control: Bacillus thuringiensis (Bt) spray kills caterpillars without harming other insects
- Encourage predators: wasps, blue tits, and robins all eat cabbage white caterpillars
See all pest and disease guides: Garden Problems UK
Fix The Cause, Then Plan The Next Crop
Troubleshooting works best when you improve the growing conditions and record what changed for the next season.
Plan the next step
Use the printable UK Vegetable Garden Planner to turn this guide into sowing dates, bed layouts, and weekly garden tasks.