Larvae are the damaging stage of this pest. Generally, European
chafers prefer to feed on cereal plants like turf and wheat. Larvae
can feed on just about anything and have been found damaging the
fine roots of broadleaf plants and conifers. In turf, larvae feed
in the root zone up to the root crowns of turf grass. Heavy infestations
cause browning and death of turf, especially as drier months begin.
Secondary pests, such as raccoons and skunks will peel back turf
to feed on the grubs causing significant damage to lawns.
Image Source - BC Ministry of Agriculture
Monitoring for white grubs is very similar to that for crane fly.
The threshold for white grubs is dependant on the health of the
turf. Generally, 5 to 10 grubs per square foot warrant management
tactics. Monitoring adult flight can be fairly obvious because of
their swarming behavior and the noise they make.
Managing the European Chafer will not be easy. Reports across the
country have alluded that this pest tolerates many insecticides
and the currently recommended ones are unsavory for birds or pollinators.
This is why surveying for potential introductions of this pest
is very important and crucial for management of the European Chafer.
Many thanks to Todd Murray for some of the information
contained in this article.