Pea moth (Cydia nigricana)

Overwintering in a cocoon in the soil, this 6mm long, brown moth emerges in May and June and lays its eggs on and around the pea flowers from (mid) June to July. The black-headed caterpillars move into and live in the developing pod, eating their way through the peas to greet you at about 8-10mm long when you open the pod. If not picked, they will eat their way out of the pod, fall to the soil and prepare their cocoon for winter.


  • The pinhead-sized, flat eggs are difficult to spot
  • First sign of infection is usually when the pod is opened. A damaged pea or two, a caterpillar or two and caterpillar poo (frass) are a sure sign of pea moth

Prevention & control

  • This bane of pea growers is best avoided by ensuring peas flower before mid June or after July when the adults are laying:
    • A fast-maturing early crop - to flower before mid-June: sow in autumn under cloches, indoors in late winter or under cloches in early spring
    • A mildew-resistant late crop - sow after mid-May
  • Physical barriers such as fleece or enviromesh are also successful
  • Turn the soil over to expose cocoons to predators in the autumn and, as always, practise good crop rotation
  • The unaffected peas in the pod are normally fine - just rinse to remove and traces of frass
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