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Pea moth
Common name: Pea moth
Latin name: Cydia nigricana
Plants affected:
Vegetable peas, but not mangetout types where the pods are harvested before the seeds have developed.
What is it
Pea moth is a pest.
Symptoms
Pea moth is a widespread pest in gardens and allotments in Britain. The caterpillars feed on the peas inside the pea pods and are only noticed when the pods are shelled, revealing tell-tale pellets of excrement next to partially eaten peas.
Cause/biology
The pea moth caterpillars are up to 14mm (1/2in) long and are creamy white with small black dots and a dark brown head. Pea moth has one generation a year and adult moths emerge from early June to early August, with peak activity in July. Eggs are laid on the foliage and, after hatching, the caterpillars bore into the developing pea pods and start feeding on the developing peas. When they have completed their feeding in late summer, they go into the soil where they overwinter as non-feeding larvae. Pupation takes place in the spring.
Control
Quick maturing pea cultivars can be sown early or late so they flower outside the pest's June to early August egg-laying period. For mid season peas, the plants can be covered with a horticultural fleece during June to mid August to stop pea moth females laying eggs on the plants. Crop rotation is essential, otherwise moths may emerge underneath the fleece from overwintered larvae and pupae in the soil.
Mangetout pea pods are eaten before the peas fully develop, so should need no protection.
Peas can be sprayed with bifenthrin (Bayer Sprayday Greenfly Killer Plus, Doff All In One Garden Pest Killer, Scott Bug Clear Gun) to control the newly hatched caterpillars before they enter the pods. Apply the insecticide 7-10 days after the onset of flowering. In most years, only a small proportion of the peas are damaged and this level of damage may not justify the use of control measures.