Chafer grubs are the soil-dwelling larvae of chafer beetles. Depending on the species of chafer they either feed on decaying plant material or plant roots.
Chafer beetles belong to the beetle family Scarabaeidae, and there are over 80 species in Britain. Many species are rare or of local occurrence. There is, unfortunately, a handful of species that can cause damage in gardens.
Some species of chafer grub eat the roots of grasses and other plants. Evidence of their activities can be seen in several 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 (jays, magpies, rooks and crows), badgers and foxes tear up turf in order to access the grubs to feed on them.
Damaging populations can be very localised and sporadic.
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, can be up to 18mm (almost ¾in) long.
Chafer grubs, dung beetles and stag beetles all have similar looking grubs. Only those grubs found in turf are likely to be chafers damaging lawn roots.
Other less troublesome species of chafer grubs can also occur in turf and garden borders, such as the cockchafer (Melolontha melolontha), summer chafer (Amphimallon solstitialis) and brown chafer (Serica brunnea). These can have larvae up to 30mm (over an inch).
Similar root damage in lawns can also be caused by leatherjackets but churning up of the turf by other animals is less likely where leatherjackets are the problem.
How can you get rid of chafer grubs?
Repair damaged turf by re-sowing with grass seed or laying turf in mid to late spring when the chafer grubs have moved deeper into the soil to pupate.
There is also a Biological control. You can buy pathogenic nematodes, usually Heterorhabditis bacteriophora, which kill the larvae by infecting them with a fatal bacterial disease. These microscopic animals can be watered into the lawn when the ground is moist and soil temperature ranges between 12-20ºC. The nematodes are available by mail order from biological control suppliers and from some garden centres. The turf around the edge of affected areas should be targeted to deal with larvae spreading from infestation “hot spots”. However, by the time areas of damage become apparent, the soil may be too cold for nematodes to be effective. As a preventive measure, nematodes can be applied in July to September. Nematodes should be applied as soon as possible after purchase, following the suppliers’ instructions. It may be necessary to water the lawn before and after application to ensure the soil is sufficiently moist for nematode activity and survival
Lures and traps are available for adult beetles however their effectiveness is uncertain. Adults may be trapped after the damage has already occurred.
There are no pesticide controls for chafer grubs in lawns which can be applied by home gardeners.
We have helped many clients who have chafer grub problem. If you would like our assistance contact us now. Tel 01522 868717 or email landscapinglincolnshire@gmail.com