What's eating my broad bean?

Black bean aphid is the defining pest of broad beans, typically arriving in late spring to infest and distort shoot tips. Pea and bean weevil notches leaf margins in early spring. Chocolate spot fungus weakens overcrowded plants in wet weather. Mice steal seeds at sowing. Early autumn sowing gets ahead of the worst aphid pressure.

Large, dense black colonies on stem tips and shoot growing points from late spring; leaves curl; plants weakened; pods may be distorted Pinch out the top 10 cm of stem once lower pods are setting — removes the primary aphid habitat; insecticidal soap or neem spray; encourage parasitic wasps

Distinctive scalloped notches around the margins of leaves, especially on young plants in early spring; not usually fatal but slows growth Encourage vigorous plant growth so plants outgrow damage; pyrethrin spray in severe infestations; remove plant debris where adults overwinter

Seeds dug up and eaten at or just after sowing; entire rows may fail if unprotected Set spring traps baited with peanut butter along rows; sow in modules under cover and transplant; protect outdoor sowings with wire mesh pegged over the row

Brown/chocolate-coloured spots on leaves and stems; severe infection in wet conditions turns plants black and kills them Ensure wide spacing for airflow; avoid waterlogged sites; apply copper-based fungicide at first sign; autumn-sown crops are usually less severely affected