Sweet Potatoes: Pests & Diseases
Sweet potatoes need a long, warm season, so in much of the UK they perform best in a greenhouse, polytunnel, conservatory or very sheltered sunny bed. Plant slips only after conditions have warmed. Loose, free-draining soil and careful watering encourage smooth tubers rather than cold, wet rot.
Common pests
Slugs and snails chew young foliage and may damage shallow or exposed tubers. Aphids can colonise tender tips and distort growth. In warm protected spaces, glasshouse whitefly gathers beneath leaves, while red spider mite causes pale stippling and fine webbing in dry conditions. Vine weevil may occasionally affect container plants. Mice can sometimes nibble harvested or curing tubers if storage is insecure.
Common diseases
Sweet potatoes are generally trouble-free in UK gardens when kept warm. Cold, wet soil is the main cause of tuber and root rot, often accompanied by soft, discoloured tissue. Grey mould may affect damaged foliage or stored tubers in humid conditions. Viral diseases can cause mottled, distorted leaves and poor growth, but are best avoided by starting with healthy slips rather than saved, suspect material.
Prevention
Plant into warm, loose, free-draining soil or raised containers, leaving enough room for foliage to dry after watering. Do not plant out too early and protect young plants with fleece if nights turn cool. Use healthy slips, avoid waterlogging, and water the soil rather than the leaves. Keep the growing area tidy, remove damaged foliage, and rotate away from previous poorly performing beds where practical.
Non-chemical control
Hand-pick slugs and snails in the evening and use barriers around young plants where suitable. Check shoot tips for aphids and wash small colonies away with water; flowering plants nearby support hoverflies and ladybirds. In protected spaces, use yellow traps only for monitoring whitefly and encourage biological predators where available. Improve humidity and ventilation to discourage red spider mite, and use biological nematodes for vine weevil larvae in warm, moist container compost.
What to look for
Check newly planted slips every few days for slug damage, wilting and cold stress. From late spring through summer, inspect leaf undersides weekly for aphids, glasshouse whitefly, red spider mite speckling and webbing. Before lifting, check that soil is not saturated and examine any exposed tubers for soft rot or chewing.
Tips
Lift tubers before cold autumn weather and handle them gently, as bruises invite rot. Cure them somewhere warm, dry and airy before storing. Avoid chilling in storage, and eat any nicked or damaged tubers first rather than keeping them for long.
Sweet Potatoes pests & diseases: frequently asked questions
What are the common pests of sweet potatoes?
Slugs and snails chew young foliage and may damage shallow or exposed tubers.
What diseases affect sweet potatoes?
Sweet potatoes are generally trouble-free in UK gardens when kept warm.
How do I prevent pests and diseases on sweet potatoes?
Plant into warm, loose, free-draining soil or raised containers, leaving enough room for foliage to dry after watering.
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.