Chafer Grub

Chafer grubs can devastate your lawn.

They are creamy coloured, approx 1.5 cm in length and have distinctive legs. They are often mistaken for vine weevils - but these tend to be smaller and do not have legs.

Like Leatherjackets they attack grass roots causing identical symptoms, but being larger and creamy coloured makes them easier to identify. They live below the soil surface and actually chew off the roots of the grass.

After they destroy the grass roots, the lawn will appear unhealthy, weak or possibly yellow in patches, as if the lawn is drying out.

Birds will also feed on grubs, leaving pencil sized holes.

Often the damaged turf will roll back like a carpet.

Some grubs complete their life cycle in one year. Others require three years to complete their life cycle.

Chafer grubs survive in the winter as larvae in the soil. In the early spring they begin to feed again. Later in the spring and summer they enter a resting stage (pupae) then hatch into adult beetles.

A lot of beetles can mean a grub problem later. (The beetles do not damage lawns). Beetles lay their eggs, which hatch into grub larvae. The larvae feed voraciously, which results in significant stress to your lawn. Serious damage can occur in spring, summer and autumn. If the problem is ignored the patches will get larger.

Chafer Grubs - The eggs hatch and the grubs feed on grass roots from July until late autumn before burrowing deep into the ground to pupate. These grubs then lay dormant deep in the ground under the soil before moving to the surface the following spring to emerge as beetles in May / June and starting the process again.

There is therefore one opportunity a year to kill these grubs when they are active in the soil, near the surface and the soil temperature is 12C. This is normally July and August.

Adult Chafer Grubs - The adult Chafer Beetles emerge in May/June from the lawn and will mate and immediately lay eggs.

Unfortunately these are often laid in the same place re-infesting the same lawn each year so the problem will progressively get worse year after year.

Inspect the lawn in areas of discoloration by cutting a 6" X 6" section of turf on three sides and peeling back the sod and examine the upper 2 inches of root zone for the presence of white grubs.

Examination is aided by shaking or breaking the sample, and by probing through the soil and roots with a sharp instrument such as a pocket knife or screwdriver. Since chafer grubs do not distribute themselves evenly throughout the turf, it is essential that enough areas are examined to find out how extensive the infection is.

The symptoms of both Leatherjackets and Garden Chafer Grubs are the same :

• Grass growth slows and yellow patches appear.
• Grass is easily pulled up, with little or no root growth.
• Starlings peck at the grass in an attempt to eat the grubs.

To cure the problem:

A nematode based insecticide can be watered into the soil in late summer when the soil is moist but warm. Rolling the grass in the spring with a heavy roller may crush the grubs.

Once the damage has been spotted, the grubs are usually too large to be effected by chemicals. If this is the case the only cure is to take up the entire lawn, thoroughly rotavate the area and replace the turf. This will kill the majority of the grubs and destroy their environment.