What's eating my 'purple sprouting' broccoli?

Purple Sprouting Broccoli overwinters in the ground, giving brassica pests a long window of attack. Cabbage white caterpillars are the main growing-season pest; cabbage aphids mass on shoots in late season; and in the UK, wood pigeons are especially destructive through winter and early spring when PSB is most vulnerable and valuable.

Caterpillars graze leaves from summer through autumn; late-instar larvae are large enough to devour an entire leaf overnight and contaminate sprouts. Fine insect-proof netting over the whole crop from transplanting. Bt spray for exposed plants. Remove caterpillars by hand during morning inspections.

Waxy colonies form deep within new shoots from late summer; hard to dislodge from PSB's dense growth habit; transmits viruses. Inspect shoots weekly from August. Strong water jets early in infestation. Neem oil or insecticidal soap sprays. Parasitic wasps naturally colonise if not disrupted by broad-spectrum pesticides.

Strips overwintering plants to bare stalks; most damaging January to March just before and during sprouting — can destroy an entire crop in days. Net plants with garden bird netting supported on hoops so netting does not lie on plants. Check regularly for gaps. No deterrent is reliable without physical exclusion.

Maggots attack roots of freshly transplanted PSB in spring and late summer, causing wilting and blue-tinged leaves; transplant failure in young crops. Fit brassica root-fly collars (10–15 cm discs) around each stem at planting to prevent females laying eggs at the soil surface.