Chafer Grubs: Understanding and Top 3 Control Measures

Chafer Grubs are the larvae of the Chafer Beetle and although not as common as Leather-jackets they cause similar problems by feeding of the roots of the grass.

Chafer grub

Chafer Grubs are a pale colour with distinctive legs and are typically about 15-20mm in length

The adult Chafer lays its eggs in early summer, usually May and June (depending on the weather conditions). They hatch shortly after and will feed on the grass roots until late September to early October. After this period the Chafer Grubs will move deeper into the soil where they will stay during the winter months, finally emerging on the surface as Beetles in the spring time.

The most extensive damage is usually caused in August and September as the grubs are reaching maturity. The damage from Chafer Grubs is seen in the form of thinning, yellow turf in the early stages eventually developing into irregular dead patches on the lawn. The grass can easily be pulled up as the roots have been eaten and damaged.

Further damage is also caused by wildlife such as birds like crows and magpies, as well as foxes and badgers which all feed on Chafer Grubs. These animals can cause extensive damage as they tear up the turf as they search for the grubs.

Prevention of these grubs is very difficult, so be vigilant and keep a look out for birds digging up the lawn looking for grubs (Note: These symptoms can also be birds seeking Leather-jackets). Once the problem has been positively identified the lawn can be treated with a nematode based product available from most good garden centers.

Top 3 Control Measures

Chafer grubs are the larvae of chafer beetles and can be a significant menace for gardeners and lawn enthusiasts. These white, C-shaped grubs feast on plant roots, especially grass, causing noticeable patches of brown, dying grass in lawns. If left unchecked, their presence not only damages the turf but can also attract predators like birds and badgers that further ruin the lawn while digging for these grubs. Let’s delve into the top three methods to control the proliferation of chafer grubs.

1. Biological Control with Nematodes:

  • Nematodes: These are microscopic worms that act as a natural predator to chafer grubs. Specifically, the nematode species Heterorhabditis bacteriophora can be effective against chafer grubs.
  • Application: The nematodes are mixed with water and applied to the affected lawn areas. They penetrate the grubs, releasing a bacteria that proves fatal to the grub.
  • Timing: It’s crucial to apply nematodes when the grubs are young and near the soil surface, typically in late summer to early autumn.
  • Soil Conditions: Ensure the soil is moist before and after application. Nematodes require moisture to move in the soil and reach their target.

2. Lawn Care and Maintenance:

  • Aeration: Regularly aerating the lawn can disrupt the life cycle of the chafer grub. It involves making holes in the soil to allow air, water, and nutrients to penetrate the grassroots.
  • Dethatching: Remove thatch (a layer of organic matter) from the lawn. Thicker thatch layers provide an ideal environment for chafer beetles to lay their eggs.
  • Mowing: Keep the grass slightly longer. Short grass exposes the soil, making it more attractive for female chafer beetles to lay eggs.

3. Chemical Control:

  • Insecticides: There are specific insecticides available that target soil pests like chafer grubs. However, their use might be restricted in some regions due to environmental concerns.
  • Application: Follow the manufacturer’s guidelines closely. The effectiveness often depends on the timing and method of application.
  • Safety: Always wear appropriate protective equipment when handling and applying chemicals. Ensure that pets and children are kept away from treated areas for the duration specified on the product label.

Conclusion

Chafer grubs, while small, can wreak havoc on lawns and gardens. Early identification, combined with one or more of the above control measures, can help manage and reduce the damage caused by these pests. It’s essential to monitor the lawn regularly and act promptly if chafer grub activity is suspected. Whether you choose biological control, lawn care practices, or chemical treatments, timely intervention is the key to a healthy, grub-free lawn.

Oliver Thompson
Lawn Care Expert

About Oliver: Oliver Thompson, a seasoned lawn care expert from the Cotswolds with over two decades of experience, invites all enthusiasts to join him in exploring the world of lawns, sharing knowledge, and fostering a vibrant community of lawn enthusiasts. More info

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