Why Are the Edges of My Pea Leaves Notched and Scalloped?

A regular pattern of semi-circular or U-shaped notches bitten out of the margins of pea leaves — particularly on young plants in early spring — is the characteristic feeding damage of the pea and bean weevil (Sitona lineatus). This small (4–5 mm), grey-brown beetle with distinctive pale striping on its back feeds on the leaf margins of peas, beans, and other legumes, creating a scalloped edge that is unmistakable once you know what caused it. The damage looks alarming but is usually not serious on established plants.

The pea weevil lifecycle

Adult weevils overwinter in hedgerows, grass margins, and leaf litter, emerging in spring to feed on the first legumes available — typically peas sown in March and April. They feed mainly at night and drop to the soil when disturbed, making them hard to spot. After mating, females lay eggs in the soil near pea roots; the larvae hatch and feed on root nodules (the nitrogen-fixing structures), though this underground larval feeding is generally not damaging to the host. Adults complete the season and return to overwintering habitats in autumn.

When is weevil damage serious?

On well-established pea plants with multiple leaves already formed, weevil notching is cosmetic — the plant is growing faster than the damage is inflicted and the notches do not affect yield. However, on very young seedlings (two to four leaves) in cold, wet spring conditions where growth is slow, severe weevil attack can strip so much leaf area that growth is significantly set back, or the growing tip is damaged. Small, struggling seedlings are most at risk. Quick-establishing seedlings in warm conditions generally shrug off weevil feeding without difficulty.

Managing pea weevil

Fleece over young seedlings from emergence until they have at least six leaves provides a physical barrier that prevents adult access during the vulnerable stage. Once plants are 20–25 cm tall and growing vigorously, remove the fleece — plants are past the at-risk stage. Early sowings that produce large seedlings quickly are less affected than late April sowings that germinate slowly into cold soil. No pesticide is approved for pea weevil in home gardens; if damage is very severe on tiny seedlings, resowing under protection is the most practical solution.