The Ultimate Guide to Chafer Grubs in Lawns

Protect your lawn from destructive Chafer Grubs with expert insights into identification, treatment, and prevention.

Key Takeaways

• Chafer Grubs are creamy-white larvae of Chafer Beetles, feeding on grass roots and causing yellowing, spongy turf.
• Look for wildlife damage (birds, badgers) and dead grass patches as infestation signs.
• Treat with nematodes between July–October when soil temperatures exceed 12°C.
• Maintain lawn health through aeration, proper watering, and balanced fertilisation to deter beetles.
• Chemical treatments require professional application; nematodes are the only legal DIY option.

What Are Chafer Grubs?

Chafer Grubs are the larvae of Chafer Beetles (Phyllopertha horticola and Hoplia philanthus). These C-shaped, creamy-white pests with brown heads feed on grassroots, weakening turf and leaving lawns vulnerable to secondary damage from predators like birds and foxes. Adults emerge in May–July, laying eggs in soil, which hatch into grubs within two weeks.

Signs of a Chafer Grub Infestation

1. Yellowing or Dead Patches: Grass loses vigour as roots are destroyed.
2. Spongy Turf: Damaged roots loosen soil structure.
3. Wildlife Activity: Birds, badgers, or foxes tearing up turf to feed on grubs.
4. Larvae in Soil: Lift weakened turf to find grubs 1–3cm long.

The Chafer Grub Lifecycle

Grubs cause most damage in autumn and spring. Treat infestations before September while larvae are near the surface.

How to Control Chafer Grubs

1. Biological Control: Nematodes

Heterorhabditis bacteriophora nematodes are microscopic worms that infect and kill grubs within 10–14 days.

Application Guide

• When: July–September (soil >12°C).
• Steps:
  1. Aerate and mow the lawn.
  2. Mix nematodes with water and spray evenly.
  3. Water daily for 14 days to keep soil moist.
• Effectiveness: Kills 90%+ larvae; safe for pets and wildlife.

2. Professional Chemical Treatments

Products like Acelepryn (applied by licenced professionals) target young grubs. Requires minimal soil disruption but is costly.

3. Cultural Practices

• Aerate: Reduces soil compaction, improving root health.
• Top Dressing: Apply sand-soil mix to improve drainage.
• Avoid Overwatering: Damp soil attracts egg-laying beetles.

Long-Term Prevention Strategies

1. Encourage Predators: Attract birds, hedgehogs, and ground beetles.
2. Pheromone Traps: Deploy in May to capture adult beetles.
3. Healthy Lawn Care:
   • Mow at 4–5cm height.
   • Apply autumn fertiliser to strengthen roots.
   • Scarify to remove thatch.

FAQs

Q: Can Chafer Grubs kill my lawn?

A: Yes—severe infestations destroy roots, causing irreversible damage. Early treatment is critical.

Q: Are nematodes safe for vegetable gardens?

A: Yes. They target only Chafer Grubs, posing no risk to plants or humans.

Q: Should I replace my lawn after infestation?

A: Overseed damaged areas with resilient grass mixes like perennial ryegrass. Use top dressing to level the surface.

Act Now to Save Your Lawn

Chafer Grubs threaten lawns nationwide, but timely intervention with nematodes and proactive lawn care can restore your turf’s health. For severe cases, consult a professional pest control service.