Cauliflower: Pests & Diseases
Cauliflower rewards careful growing with compact white curds, but it is less forgiving than many brassicas. Even growth, fertile ground and dependable moisture are important, while fine mesh keeps pests from damaging leaves that are needed to feed and protect the developing curd.
Common pests
Cabbage white caterpillars from large and small white butterflies chew leaves and may hide around the curd. Cabbage moth caterpillars, mealy cabbage aphid and cabbage whitefly are also common. Cabbage root fly maggots can make transplants wilt and fail. Flea beetles produce shot-holes on small seedlings, and pigeons readily strip leaves from plants without protective netting.
Common diseases
Club root makes roots swollen and distorted, leaving cauliflower stunted and prone to wilting, especially on wet acidic soil. Downy mildew causes pale upper-leaf patches and grey growth below. White blister produces white raised spots, while powdery mildew may affect older leaves. Ringspot gives dark circular lesions. Black rot spreads from leaf edges, causing yellowing and blackened leaf veins.
Prevention
Use a several-year rotation that excludes all brassicas from the same bed. Improve drainage, test soil and lime it if acidic, particularly where club root has occurred. Choose resistant varieties for affected plots. Plant into firm, fertile ground at suitable spacing, keep water even and remove diseased leaves. Fit fine insect-proof mesh from planting onwards; it is the single most effective all-round brassica defence.
Non-chemical control
Secure fine mesh tightly at soil level to block butterflies, pigeons and cabbage root fly. Place brassica collars around stems when setting out plants. Inspect leaf undersides and around the curd, removing eggs, caterpillars, aphid colonies and badly infested leaves by hand. Encourage natural predators through flowering companion plants. Water stressed young plants thoroughly and replace only after checking whether club root is present.
What to look for
Start checks immediately after planting for root-fly wilting, flea-beetle shot-holes and pigeon damage. From late spring through autumn, inspect weekly beneath leaves and around curds for butterfly eggs, caterpillars, aphids and whitefly. Look after rainy weather for downy mildew, and investigate any plant that remains small or limp.
Tips
Keep leaves healthy because they feed the curd; tie a few over a forming white curd if the variety does not self-wrap. Harvest when the curd is compact and smooth. Avoid sudden drought followed by heavy watering, which encourages uneven growth.
Cauliflower pests & diseases: frequently asked questions
What are the common pests of cauliflower?
Cabbage white caterpillars from large and small white butterflies chew leaves and may hide around the curd.
What diseases affect cauliflower?
Club root makes roots swollen and distorted, leaving cauliflower stunted and prone to wilting, especially on wet acidic soil.
How do I prevent pests and diseases on cauliflower?
Use a several-year rotation that excludes all brassicas from the same bed.
General guidance for UK home gardens, focused on prevention and non-chemical control. The RHS or a local garden centre can help with tricky cases. Page updated 18 Sep 2026.