Growing Brassica Seeds & Pest Control

The family of brassica plants is a large group of vegetables which are amongst the most popular of vegetable seeds grown in Ireland. The family of brassicas includes cabbage, cauliflower, broccoli, kale, sprouts and Chinese cabbage.  In terms of crop rotation groups, the brassica rotation group also includes swedes & turnips. This is because brassicas are affected by the same soil borne pests as turnips & swede and so it makes sense to grow & move these vegetable together


Below is a list of the most common pests & disease you are most likely to see when you grow brassica vegetable seeds:

Clubroot  – Caused be a soil borne fungus, clubroot is the most damaging disease that will affect brassicas & turnips. The fungus affects the roots of these plants causing the roots to swell & become misshapen resulting in poor yields & death of plants. Club root is spread by sowing seeds into infected soils & then moving seedlings out to vegetable plot. It can also be spread by walking on infected soil and spreading fungus on soul of foot
Control options include choosing resistant seeds such as ‘Kilaton’ cabbage seeds, ‘Marian Swede seeds & ‘Trixie’ Cauliflower seeds. Control clubroot by only transplanting seedling out once they are at least 10cm in height, adding lime to soil to increase pH, improving soil drainage
Cabbage Root Fly – The larvae of the cabbage root fly causes the damage. The fly will land on brassica plants & lay eggs at the base of the stem, at soil level. The larvae will hatch in the soil & feed on the plant’s roots. Symptoms are stunted growth & foliage turning purple-yellow and die

Control options include the use of cabbage collars – this will prevent the larvae from burrowing down into the soil. The collars should be at least 12 cm in diameter

Brassica Whitefly – Similar to the greenhouse aphids, the brassica whitefly can infect plants, feeding on the foliage. As they feed they drop a substance called honeydue on the lower leaves – this leaves a sooty mould to the leaves which give black & sticky
Cabbage White Butterflies – If you grow cabbage from seed or other brassicas & lettuce then you will need to control against butterflies. The cabbage butterfly is a white butterfly that lays eggs on the underside of cabbage leaves. The larvae hatch & feed on the cabbage plant leaves & can destroy plants. The best control option is to prevent the butterfly from laying the eggs on the foliage – This can be done using netting
Pigeons – The fastest way to destroy cabbage plants will be to encourage pigeons to your vegetable plot. These birds can feast on your crop are destroy them completely in one sitting. Use bird scares to repel the pigeon