Pests & diseases › Blackfly
Blackfly
Black aphids that swarm growing tips of broad beans, nasturtiums and beetroot.
Symptoms
- Dense black clusters on the top 10cm of broad bean stems
- Wilting tips and distorted pods
- Honeydew and sooty mould further down the plant
Lifecycle
Overwinter on spindle bushes, migrate to beans May–July. Peak damage in June.
What to do
- Pinch out the growing tip of broad beans once the lowest flowers have set — removes the bit blackfly love most
- Jet of water to dislodge colonies
- Soft soap spray
- Encourage ladybirds and parasitic wasps
If it's bad
- Pyrethrum spray if you must — avoid when bees are working the flowers
Stop it coming back
- Sow broad beans in autumn — they're tougher and crop before peak blackfly
- Plant summer savory near broad beans (traditional companion)
Crops it goes for
Plan the plot, track every sowing, cook the harvest
Sowing reminders and harvest forecasts for your own frost dates, the Seed Tin, Scan Centre for any label or packet, and the Potty Mouth Garden Club. Free to start.