Cabbage root fly collars

How it works

A disc laid flat on the soil around the stem stops the fly laying at the stem base, and gives ground beetles a warm dry hiding place from which to eat any eggs laid nearby.

Recipe

Cut 12-15 cm discs of cardboard, carpet underlay or roofing felt with a slit to the centre.

How to apply

Fit snugly around the stem at transplanting time, flat on the soil.

Targets — pests

Cabbage root fly

Targets — diseases

Not recorded — the field is blank rather than guessed.

Supplies: Cardboard or felt discs

Days to harvest after spraying: 0

Best months: March, April, May, June, July, August

Cautions

Must sit flat with no gap at the stem. Lift and check occasionally in wet weather.

The thing people get wrong

Costs nothing and saves a whole brassica bed. The wilting-then-dying young cabbage that people blame on drought is nearly always root fly maggots - by the time you see wilt, the roots are gone.