Peas can be attacked by various pests throughout the growing season. The most common pests causing damage are the black bean aphid (Aphis fabae), the pea aphid (Acyrthosiphon pisum), the pea weevils (Sitona spp.), the pea beetle (Bruchus pisorum), and the pea moths (Laspeyresia nigricana and Laspeyresia dorsana).
Black Bean Aphid (Aphis fabae)
This aphid overwinters as eggs on shrubs (Evonymus europaeus) or, less commonly, on Viburnum opulus. In spring, the eggs hatch into foundress aphids that develop 3 – 4 wingless generations. Winged generations migrate to summer hosts in mid-April, when air temperatures reach 15°C. This aphid has a high reproductive potential (under favorable conditions, a generation can develop in 10 – 12 days) and can produce 13 – 19 generations per year. Higher relative humidity and temperatures of 20 – 24°C are most favorable for the development of this pest. It typically returns to its winter host in September, where females lay overwintering eggs. Direct damage is caused by piercing and sucking sap from leaves and stems, while indirect damage is from virus transmission.
To control the black bean aphid, insecticides based on pirimicarb and imidacloprid are used.
Pea Aphid (Acyrthosiphon pisum)
This aphid overwinters as eggs near the root collar of perennial legumes or on plant debris. In April, the eggs hatch into foundress aphids that produce wingless generations. Winged aphids appear in May and fly to pea plants. This aphid also has a high reproductive potential (each generation can develop in about 10 days) and can have up to 19 generations per year in warm and moderately humid weather.
Direct damage is caused by piercing and sucking sap from leaves and stems, while indirect damage includes virus transmission.
Chemical control of aphids involves insecticides based on pirimicarb and imidacloprid.
Pea Weevils (Sitona spp.)
Pea weevils are beetles that cause damage by feeding on leaves, often along the edges. Significant damage can occur to young crops in the spring.
They have one generation per year. They overwinter as sexually immature adults on leguminous crops and emerge in April to start feeding. Pea weevils can be found until mid-summer, during which time females gradually lay eggs. The larvae burrow into the soil after hatching, first feeding on fine roots and later on nitrogen-fixing nodules. Larval development takes 6 – 7 weeks, after which they pupate. Although they emerge in late August and early September, they only become sexually mature the following spring.
Control measures are applied when 10% of the leaf area is damaged or when more than 2 – 3 weevils per square meter are found.
Pea Beetle (Bruchus pisorum)
This beetle attacks peas for both human and animal consumption. The pea beetle overwinters in pea storage facilities or in natural shelters, including under tree roots. Adult insects emerge in the field in late spring when peas are in bloom. They feed on peas, mate, and then females lay eggs on the pods. Larvae that hatch burrow into pea seeds. Each female can lay 150 – 200 eggs. The complete development of the pea beetle typically takes over two months. This pest usually has one generation per year, indicating it does not infest storage facilities but rather the adult insect migrates to the field after development to feed. The damage caused to peas is significant as the insect consumes the nutrient-rich part of the seed and can damage the germ, reducing germination and market value. The pea beetle is a typical monophage (attacking only peas).
Chemical control of the pea beetle is determined using sweep nets; when 2 – 3 beetles are found in 25 sweeps, insecticides should be applied, or as soon as the first pods show signs of infestation. Due to the prolonged egg-laying period, treatment should be repeated after 10 – 14 days.
Pea Moths (Laspeyresia nigricana, Laspeyresia dorsana)
The larvae overwinter in cocoons in the soil, pupating in the spring, and adult moths emerge from May to August. The moths are nocturnal. They lay eggs on the calyx leaves and young pods during flowering. The larvae initially mine the leaves and later burrow into the pods, damaging the seeds while they are still soft. Once the seeds harden, the larvae cease feeding. There is one generation per year.
Peas grown for canning require thorough cleaning.
Insecticide treatments abroad are conducted during flowering with insecticides based on phosalone and pyrethroids. The treatment is repeated after 10 – 12 days.
Other Pests Affecting Peas:
- Bean root flies (Delia platura and Delia florilega)
- Pea thrips (Kakothrips robustus)
- Pea midge (Contarinia pisi)
- Pea cyst nematode (Heterodera goettingiana)
Key to Identifying Pests on the Underground and Ground-Level Parts of Pea Plants:
From the book “Vegetable Pests” by M. Maceljski and collaborators
- Root damage, stunted growth: Soil pests
- Stunted growth, swollen stem base, red stems, and pods: Stem nematode
- Stunted growth, yellowing leaves, rootlet dieback: Free-living nematodes
- Stunted growth, yellowing leaves from the base upwards, white cysts on the roots: Pea cyst nematode
- Root swellings: Root-knot nematodes
- Young bean and pea plants wilt, white larvae up to 7 mm long at the root collar: Root flies
Key to Identifying Pests on the Above-Ground Parts of Legumes:
From the book “Vegetable Pests” by M. Maceljski and collaborators
- Bean leaves speckled with small white dots, yellowing prematurely and falling off, fine webbing with tiny spiders on the underside: Red spider mite
- Small black insects on the underside of leaves and top of the stem: Black bean aphid
- Colonies of green insects on the underside of leaves: Pea aphid
- Bean leaves gnawed at the edges immediately after emergence (resembling oak leaves): Pea weevils
- Irregular leaf damage, slime trails: Slugs
- Stunted pea and bean shoots, swollen flowers not setting pods: Pea midge
- Flowers and pods of peas and beans with silvery shiny spots that later turn brown, stunted pods: Pea thrips and other thrips
- Pea pods eaten from the inside and contaminated: Pea moths
- Bean seeds perforated with one or more white, legless larvae inside: Bean weevil
- Pea seeds perforated with one larva inside: Pea beetle
