Dew worms can cause unsightly bumps and lumps in your lawn, but keeping your grass healthy is the best defense, according to gardening expert Gerald Filipski. In a recent column, Filipski addressed a reader's concern about a 25-year-old lawn near a golf course that developed small mounds with tiny holes in the center.
Identifying the Problem
Filipski identified the issue as dew worms, which thrive in older lawns with significant thatch buildup. Cultural control is essential since no chemicals are registered for this pest. A healthy lawn helps keep worms below ground, but consistent maintenance is key.
Effective Control Measures
- Aerate twice a year — in spring and fall to reduce compaction and improve drainage.
- Dethatch annually — professional dethatching removes excess thatch where worms breed.
- Water deeply but infrequently — apply about 2.5 cm of water per week. Less frequent watering discourages worms from surfacing.
- Top dress with sharp sand — worms dislike crawling on rough surfaces, which can help reduce their activity.
Patience is crucial, as this is a difficult problem with no quick fix.
Wireworms in Potatoes
Another reader reported potatoes riddled with tunnels and worms, which Filipski attributed to wireworms — the larvae of click beetles. These pests create tunnels in tubers, making them inedible.
Control Strategies for Home Gardeners
- Inspect soil in spring — remove any wireworms found while digging.
- Use bait potatoes — bury them in spring and check regularly, removing larvae.
- Rotate crops — moving potato patches annually helps prevent wireworm buildup and also controls scab.
For more details, Filipski recommends the Alberta Agriculture website at alberta.ca/wireworm, which covers life cycles and control methods.
Readers can submit gardening questions to filipskigerald@gmail.com or follow him on X (Twitter) @justaskjerry01.
