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Wireworm
Agriotes spp.
PestMedium impact
Slender, yellowish-brown soil-dwelling larvae of click beetles that tunnel into roots and tubers. Most problematic in ground recently converted from grass or in plots with a long history of soil. Damage is found at harvest rather than visible during the growing season.
Currently in peak season - extra vigilance worthwhile.
Key facts
- Type
- Pest
- Active season
- Apr - Sep
- Peak season
- May - Sep
- Vulnerable stages
- Growing · Harvesting
- Spread rate
- slow
- If confirmed
- Act soon
Signs & symptoms
- -small round entry holes in tubers or roots, often with tunnelled cavities inside
- -damage revealed at harvest rather than during growth
- -plants may show no above-ground symptoms
Management
Do now
- -Lift damaged tubers or roots promptly and use them immediately if minor damage
- -Set out bait traps (buried chunks of potato or carrot) to detect and reduce populations
Prevention
- -New ground converted from grass has higher soil pest pressure - allow time and regular cultivation to reduce numbers
- -Cultivate soil regularly to expose larvae to birds and other predators
- -Grow a cover crop before potatoes in new ground to help reduce wireworm numbers
Further reading
- -Wireworms are larvae of click beetles and live in the soil for up to 5 years before pupating
- -They are most abundant in new plots converted from grass or in plots that have been uncultivated for years
- -Frequent cultivation and digging reduces populations over time