Pest
Pea moth
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Watch for | Watch for in June | Watch for in July | Watch for in August |
What it is
Pea moth is a small, greyish-brown moth, barely 15 mm across, that most gardeners never see. Its caterpillars are the problem: they live inside the pods and feed on the developing peas, so damage only shows when you sit down to shell a basket of what looked like perfect pods.
Symptoms
Inside affected pods you will find one or two creamy caterpillars with dark heads, up to about 6 mm long, along with chewed peas and little piles of dark droppings. The outside of the pod usually looks normal, though you may see a tiny exit hole once the caterpillar has left. Several damaged peas per pod is typical. Mangetout picked young often escapes because it is eaten before the caterpillars get going.
Cause
Adult moths emerge from the soil from late May and fly through June and July, laying eggs on leaves and stems of peas in flower. The young caterpillars hatch within a week or two and bore into the pods. When fully fed they drop to the ground, spin cocoons in the soil and wait there until the following summer. That is why the problem builds up where peas are grown in the same place year after year.
Control
Once the caterpillars are in the pods nothing will reach them, so simply sort through the harvest and discard spoiled peas. Pods for drying or seed are worth checking carefully. Clear the old plants after cropping and fork over the bed lightly so birds can find some of the overwintering cocoons. Chemical sprays are not worth considering in a garden.
Prevention
Timing is the strongest tool. Peas sown in March, or quick early varieties sown under cover in February and planted out, usually finish flowering before the moths are busy. Sowings made from early June flower after the main egg-laying period. For midsummer crops, cover the rows with fine insect mesh from the start of flowering until the pods are filled, sealing the edges. Move peas to a fresh bed each year.
Plants often affected
Could it be something else?
These problems share some of the same symptoms. Compare them, or run the symptom checker with these signs ticked.
Months to keep an eye out: June, July and August.
Sources
Identification and life-cycle details were checked against the references below. Text and advice are our own. See our editorial policy.