Mustard Greens: Pests & Diseases
Mustard greens are fast, peppery brassica leaves that suit containers, raised beds and repeated sowings from spring to autumn. Their speed is useful, but seedlings can be devastated by flea beetles and mature leaves readily attract caterpillars, aphids and whitefly if left unprotected.
Common pests
Flea beetles are the most obvious early pest, making many tiny shot-holes in young mustard leaves. Cabbage white caterpillars from large and small white butterflies and cabbage moth caterpillars chew larger holes. Mealy cabbage aphid can gather in shoot tips, while cabbage whitefly sits under leaves. Cabbage root fly may weaken transplants, and pigeons can graze whole rows of uncovered seedlings.
Common diseases
Club root can stunt mustard greens and produce swollen, distorted roots, especially where soil is acidic and wet. Downy mildew causes pale angular patches with grey growth beneath leaves. White blister creates raised white pustules. Powdery mildew may cover older foliage in dry conditions. Ringspot makes dark circular marks, while black rot causes yellowing at leaf edges and blackened veins in affected plants.
Prevention
Include mustard greens in the same long rotation as cabbage, kale and other brassicas, allowing several years before returning to a used bed. Lime acidic soil and improve drainage where club root is a concern. Use fresh seed, give plants room for airflow and remove diseased leaves promptly. Fine insect-proof mesh from sowing is the single most effective protection against flea beetles, butterflies, pigeons and root fly.
Non-chemical control
Keep young rows beneath fine mesh or horticultural fleece, secured at the edges, until plants are robust or harvest is near. Hand-remove eggs and caterpillars from leaves, and wash small aphid colonies away with water. Use brassica collars for transplanted plants where cabbage root fly is troublesome. Encourage hoverflies, ladybirds and parasitoid wasps by maintaining nearby flowers, and harvest heavily infested leaves rather than allowing pests to build up.
What to look for
Inspect seedlings every few days for flea-beetle shot-holes, pigeon grazing and poor establishment. From late spring to autumn, check leaf undersides weekly for butterfly eggs, caterpillars, aphids and whitefly. Look closely after damp weather for downy mildew or white blister. Pull up any badly stunted plants and inspect roots for club root.
Tips
Sow little and often for tender leaves, harvesting outer leaves while plants are young. Water regularly in dry spells to limit tough, overly hot leaves. Wash every harvest thoroughly, as tiny caterpillars and aphids often shelter along ribs and folds.
Mustard Greens pests & diseases: frequently asked questions
What are the common pests of mustard greens?
Flea beetles are the most obvious early pest, making many tiny shot-holes in young mustard leaves.
What diseases affect mustard greens?
Club root can stunt mustard greens and produce swollen, distorted roots, especially where soil is acidic and wet.
How do I prevent pests and diseases on mustard greens?
Include mustard greens in the same long rotation as cabbage, kale and other brassicas, allowing several years before returning to a used 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.