Lawnspecialist

Over 46 years of Treating and Maintaining Lawns

Insect Control

Insect Control

A combination of chafer grubs and the larger animals (Badgers & Foxes) that feed on them can quickly turn a neat lawn into something that resembles a ploughed field.

What are Chafer Grubs? 

Chafer grubs are soil-dwelling larvae of chafer beetles. They feed on plant roots.

Here are Some Symptoms 

Chafer grubs eat the roots of grasses and other plants. Evidence of their activities can be seen in a number of ways;

  • Damage to lawns is most obvious between autumn and spring when the grubs are reaching maturity
  • Patches of the lawn may become yellowish
  • Birds, particularly of the crow family (eg jays, magpies, rooks and crows), and badgers and foxes feed on the grubs, tearing up the loosened turf in the process
  • Damaging infestations can be highly localised and sporadic in occurrence
  • Chafer grubs can be found in the soil under the loose turf. They have stout white bodies curved in a C shape, light brown heads, with three pairs of legs at the head end. They are bigger than the adult beetles and, if straightened out, would be up to 18mm (almost 3/4in) long
  • Other less troublesome species of chafer grubs can also occur in turf and these can have larvae up to 30mm (over an inch)
  • Similar damage in lawns can also be caused by leatherjackets

 

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Main Symptoms

Scruffy turf with pieces pulled up by birds and animals searching for the grubs

Most active

Grubs: September – April;  Adult beetles: May – June

Leather Jackets

Leatherjackets can be damaging lawn pests and also sometimes kill small plants in flower beds and vegetableplots by eating the roots and stem bases. They are often more numerous after a wet autumn, as damp conditions favour survival of the eggs and young larvae.

What are Chafer Grubs? 

Leatherjackets are the soil-dwelling larvae of flies known as crane flies or daddy-longlegs.

Here are Some Symptoms 

How to tell if leatherjackets are a problem in your garden;

  • Lawns develop patches where the grasses turn yellowish brown and die. This can be distinguished from similar effects caused by lawn diseases or adverse growing conditions by lifting the affected turf and finding leatherjackets in the surface layers of the soil
  • Crows, magpies, rooks and starlings will search for leatherjackets in turf. These birds leave small round holes in the turf where they have inserted their beaks
  • Leatherjackets have elongate tubular bodies, up to 30mm long, and are greyish brown. They have no legs or obvious head
  • In flower beds or vegetable plots, seedlings and small plants are killed when the stems are damaged at soil level

How to Control ? 

Chemical Control

The only pesticide for use on lawns only is imidacloprid (Bayer Provado Lawn Grub Killer). The best time to apply either treatment is in early autumn when the leatherjackets are relatively small and more vulnerable.

Non Chemical Control

A biological control is available for controlling leatherjackets in lawns, flower beds and vegetable plots. This is a pathogenic nematode, Steinernema feltiae, which is watered into the turf or soil. The nematodes enter the bodies of leatherjackets and infect them with a bacterial disease. To be effective, the nematode requires soil that is well drained but moist and with a minimum temperature of 12°C (54°F).

The nematode can be obtained from mail order suppliers of biological controls.

 

Biology

There several species of leatherjackets/crane flies that feed on the roots and stem bases of lawn grasses and other plants.

The adult crane flies or daddy-longlegs mostly emerge and lay eggs in the turf or soil surface in mid-August to October. Dry soil conditions at that time can result in many of the eggs failing to hatch, so large numbers of adult flies does not necessarily mean that there will be large numbers of larvae or leatherjackets next year.

The eggs hatch a few weeks after they have been laid and the young leatherjackets begin feeding on plant roots. In cold winters, they overwinter as small larvae and do not grow large enough to cause significant damage until mid-summer. Mild winters allow the young larvae to continue feeding and they can be large enough to cause lawn problems by late winter.

When fully grown, the leatherjackets pupate in the soil. When the adult flies emerges, the pupal case is often partly pulled out of the ground and left sticking up above the lawn surface.

Main symptoms

 Lawns develop yellowish brown dead patches; seedlings collapse having been eaten at soil level; presence of leatherjackets in the soil

Caused By

 The larval stage of crane flies or daddy-lonlegs

Timing

 February-October