Scientific Name: Phyllopertha horticola
Other names: Bracken Chafer, Garden Foliage Beetle
The creamy larval stage of the Garden Chafer Beetle is quite destructive to cereal and other grass plant roots. They will cause yellowing of the grass in a similar way as Leatherjackets and when present in large numbers dead patches may appear. Also the turf can be damaged by birds such as Starlings, Magpies and Crows as they dig for the grubs; badgers can be very destructive, leaving a trail of small craters. Foxes scrape for them and moles will burrow for them, but fortunately there are no moles in Ireland.
Garden Chafer grubs are very similar in shape to those of the Cock Chafer, but are much smaller as can be seen below. The Vine Weevil grub is also C-shaped, but does not have the six legs of the chafers
The Chafer Beetles which develop from the grubs nibble on plant buds, but are not usually present in large numbers so do not cause much damage. They have chestnut brown wing case which are covered with tiny hairs. Their head, thorax and legs are dark green. They emerge from the ground in late spring.
Turning over the soil exposes them to the birds, as does watering and covering with polythene overnight to bring them to the surface. On light soils rolling in the spring crushes them as they are just below the surface, but this is unsuitable on heavy soils as it will cause compaction.
The biological control which uses a parasitic nematode called Heterorhabditis megidis is effective against the grubs of the common Garden Chafer.
The beetles can be caught in traps which use a pheromone as an attractant placed in the area in may when the Chafer Beetles are active and cover an area of about 2000 square metres. This may not catch all of the beetles, but will indicate their presence.
For chemical control Provado Lawn Grub Killer which contains *Imidacloprid is a recent introduction for the treatment of Leatherjackets and Chafer Grubs.
*Imidacloprid is a neonicotinoid compound and these have been suggested as as causative agents of colony collapse disorder (CCD) in Honeybees.
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