Kale: Pests & Diseases
Kale is one of the hardiest and longest-cropping brassicas, supplying leaves through much of the British year. Its open habit makes pests easier to find than those in headed crops, yet plants still need reliable protection from caterpillars, pigeons and the soil-borne disease club root.
Common pests
Cabbage white caterpillars from large and small white butterflies are the usual leaf chewers, joined by cabbage moth caterpillars. Mealy cabbage aphid gathers in crinkled shoots, while cabbage whitefly clouds from disturbed leaves. Cabbage root fly maggots can weaken young plants. Flea beetles make shot-holes in seedlings, and pigeons can remove whole leaves, particularly during cold weather when food is scarce.
Common diseases
Club root causes badly swollen roots, stunting and wilt, and persists in acidic, wet soil. Downy mildew gives pale blotches with grey growth on leaf undersides. White blister creates white pustules, while powdery mildew can dust older leaves. Ringspot appears as dark circular marks and may worsen in damp conditions. Black rot yellows leaf margins and can blacken veins as it spreads.
Prevention
Move kale around the plot in a rotation that keeps brassicas away from the same soil for several years. Lime acidic ground and improve drainage before planting, especially where club root is suspected. Select club-root-resistant varieties where available. Give plants enough room, firm them in, remove fallen leaves and disinfect cutting tools. Fine insect-proof mesh, fitted from planting, is the most effective protection against major pests and pigeons.
Non-chemical control
Keep plants under well-secured mesh and use brassica collars at the stem base against cabbage root fly. Hand-remove butterfly eggs and caterpillars whenever leaves are picked. Rub off small aphid colonies or prune out heavily infested shoot tips. Plant flowers nearby to support hoverflies, ladybirds and parasitic wasps. Water young wilted plants consistently, but remove club-rooted plants rather than moving contaminated soil around the plot.
What to look for
Check seedlings every few days for flea beetle damage and signs of root-fly stress. From spring to autumn, turn leaves over weekly for eggs, caterpillars, aphids and whitefly. Inspect exposed leaves for pigeon grazing in winter. After prolonged damp weather, watch for leaf spots, white blister and downy mildew.
Tips
Pick lower leaves little and often, leaving the crown intact for continued harvests. Frost can improve the flavour of winter kale. Wash harvested leaves carefully, including the folds around the midrib, to remove hidden aphids and caterpillars.
Kale pests & diseases: frequently asked questions
What are the common pests of kale?
Cabbage white caterpillars from large and small white butterflies are the usual leaf chewers, joined by cabbage moth caterpillars.
What diseases affect kale?
Club root causes badly swollen roots, stunting and wilt, and persists in acidic, wet soil.
How do I prevent pests and diseases on kale?
Move kale around the plot in a rotation that keeps brassicas away from the same soil for several years.
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.