Wireworms
Wireworms are the larvae of click beetles. They live in the soil for years and are most numerous in ground that was recently grass. They bore neat holes through potato tubers and carrots.
Pests
What it looks like
Small holes, deep tunnels.
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Neat holes Holes about 2 mm across in the skin. -
Long tunnels Narrow channels running through the tuber. -
Stiff orange larvae Shiny orange-brown larvae up to 25 mm long in the soil. -
Secondary rot Tunnels let in rot and slugs.
How to confirm it
Cut a damaged potato.
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Tunnels
Thin, straight tunnels through the flesh.
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Search the soil
Stiff, segmented orange larvae.
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Bed history
Beds recently dug from lawn are the classic site.
What to do
Reduce numbers over a few seasons.
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Harvest early
Lift potatoes as soon as they are ready; damage increases with time in the ground.
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Cultivate often
Regular digging exposes larvae to birds.
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Potato traps
Bury halved potatoes on sticks, check and remove larvae every few days.
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Grow earlies
Early potatoes escape much of the damage.
Prevent it next time
- Allow a year or two before growing potatoes in ground converted from grass.
- Keep beds weeded.
- Rotate root crops.
What not to do
Do not grow maincrop potatoes in the first year after lifting turf.
In the growing guides
Where the guides mention it, with plant-specific advice.
Sources
- Wireworms, Royal Horticultural Society