Last late summer, the adults were flying around and being batted by the Cat but their work as adults is now done! They have laid their numerous eggs in your nice green sward and now they are hatching into hungry larvae ready to start attacking your nice new grass roots. Never ever underestimate the damage that a troop of Leatherjacket larvae can inflict on a grass area.
Sadly, now the EU have banned Bayer Provado active ingredient and also the professional insecticide based on Chlorpyrifos, there are no current EU or UK approved control products to control Leatherjackets apart from Biological Controls such as Nemasys Leatherjacket Nematodes. The same applies to Chafer Beetle Larvae, only biological control and available by contacting Green Gardener online.