Wireworm
Beginner
Scientific Name
Various Coleoptera species
Identification
- Copper-coloured, cylindrical and hard-bodied
- 3 pairs of tiny legs near the head-end
- Vary in size from a few millimetres to 2 cm (1/8- 3/4 in.) in length
- Feed on roots and stems below the soil surface
- Damaged plants do not develop well and may be killed by extensive feeding or secondary infection
- Damage is often scattered randomly across the field
Often Confused With
Cutworms
Damping-off
Millipedes
Period of Activity
Wireworms are present all season. Young plants are most susceptible; therefore early-season control is critical. Wireworms have a life cycle of several years. They are likely to be present in fields with a history of the problem or in fields that have recently had sod crops.
Scouting Notes
While walking fields, look for wilted plants and/or gaps in the plant stand where transplants have died. Dig around the plant to look for feeding damage and insect larvae, to confirm the cause of the damage. Wireworm will also tunnel up the stem of transplants. Record the percentage of the field with damage.
Wireworms may be monitored in the fall (or in the early spring for later-planted crops) using bait stations. Bury whole carrots, 7.5 cm (3 in.) deep at 10 marked stations across the field. Check the stations in 2– 3 days.
Thresholds
A count of 0.5 to 1 wireworm per bait station indicates a potential problem. Make your planting and seed treatment decisions accordingly.
Advanced
Scientific Name
Various Coleoptera species
If peppers are transplanted into fields with high wireworm populations, large numbers of plants can be quickly destroyed.
Identification
Wireworms are dull brown or copper coloured, with a cylindrical, hard body. They vary in size from a few millimetres to 2 cm (1/8- 3/4 in.) in length with three pairs of legs at the head-end of the body.
Wireworms are the larvae of click beetles. They feed on the stems and roots of plants, which may develop slowly or may rapidly wilt and die. Wireworm feeding is most severe during cool, wet springs when growth of young plants is delayed. Wireworm may be present in any soil type, however; populations are often most damaging on coarse sandy-loam soils. Damage is often scattered randomly across the field.
Often Confused With
Cutworms
Damping-off
Millipedes
Biology
Wireworm eggs are often laid in small grains, sod, forage crops, or in fields with grassy weed escapes. Many wireworm species have an extended lifecycle. As a result the larvae may be present in a field for 2- 5 years.
Wireworms are most noticeable during the fall and early spring when they come to the soil surface to feed on roots and decaying residue. During the heat of the summer and the winter months, wireworm larvae will migrate deep into the soil for protection.
Period of Activity
Wireworms are present all season. Young plants are most susceptible; therefore early-season control is critical. Wireworms have a life cycle of several years. They are likely to be present in fields with a history of the problem or in fields that have recently had sod crops.
Scouting Notes
While walking fields in-season, look for wilted plants and/or gaps in the plant stand where transplants have died. Dig around the plant to look for feeding damage and insect larvae, to confirm the cause of the damage. Wireworm will also tunnel up the stem of transplants. Record the percentage of the field with damage.
Wireworms may be monitored in the fall (or in the early spring for later-planted crops) using bait stations. Bury whole carrots, 7.5 cm (3 in.) deep, at 10 marked stations across the field. Check the stations in 2– 3 days.
Thresholds
A count of 0.5 to 1 wireworm per bait station indicates a potential problem. Make your planting decisions accordingly.
Management Notes
- Plant into warm soils (>16°C or 60°F).
- Good early growth will help reduce the losses to this pest where populations are low to moderate.
- Use bait stations to identify (and avoid) fields with high wireworm populations.
