The European chafer beetle is an introduced insect that was first identified in 2001 and has since spread throughout the region. In June, chafer beetles mate and lay their eggs in lawns, where the hatched grubs (also called larvae) feed on the roots of the turf grass during summer, fall and winter. In some neighbourhoods, entire lawns appear rototilled – this damage is caused by the crows, skunks, racoons, and other predators that turn over the lawn in search of the grubs, which are nutritious to eat.
Check with your city for information on how to prevent and treat infestations and minimize damage. General defences are:
a healthy lawn, which is less susceptible to invasion;
- consider incorporating non-turf alternatives, such as micro clover or other alternative ground covers, in your yard; and
- consider biological control.
These and other control options are described in this guide to
chafer beetle best management practices, developed for use by practitioners with a role in invasive species management. This guidance has been tested locally by researchers and operational experts.
Chafer beetle and the region-wide Lawn Watering regulations
One of the more effective ways to manage chafer beetle infestations is through biological control, using one living organism to defeat another. In this case, a specific nematode (a microscopic eel worm that targets the soil-dwelling chafer beetle larvae) is released onto the affected area in late July when the chafer beetle larvae have just hatched. At this time the larvae are at their most vulnerable, and easiest to control with nematodes. Your city will have information on where to get the nematodes, and how to apply them. Note that nematodes are not a preventative measure; their application is intended to control already existing larvae.
Biological control with nematodes requires regular watering, daily if the ground is very dry, for about two weeks. While the ground should be kept moist when applying nematodes, it is important not to wash away the nematodes by overwatering. Daily watering is in conflict with the
region-wide lawn watering regulations; therefore, you will need a water exemption permit from your municipality, in order to water outside of the sprinkling regulations. You may be asked to put a sign in your window so that staff enforcing the watering regulations are aware you are using the nematode treatment. This also lets your neighbours know that you are watering within your permit.
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