Most species of chafer grub do not need control, and species such as the rose chafer may be considered beneficial.
Remove larvae of problem species from soil as they are found. Cultivation of the ground can briefly expose the grubs to predators, such as birds, and make the ground less attractive as egg-laying areas.
You can buy pathogenic nematodes, usually Heterorhabditis bacteriophora, which attack 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 range between 12-20ºC (55-68ºF). This biological control is available from some biological control suppliers and some garden centres. The ground around the edge of affected areas should be targeted to deal with larvae spreading out from infestation “hot spots”. The nematodes should be applied as soon as possible after purchase, following the suppliers’ instructions. It may be necessary to water the soil before and after application to ensure the soil is sufficiently moist for nematode activity and survival.
There are currently no pesticides available to home gardeners or the treatment of soil pests.