The most effective time to apply Leatherjacket Killer is in the late summer after daddy longlegs eggs have laid fresh eggs that have developed into Leatherjacket larvae. This normally occurs from August-October. One pack of Leatherjacket Killer will treat an area up to 100 square metres in size. Leatherjacket Killer is supplied as 2 packs of 25 million nematodes. (Please note: We regret that this item is not available to customers living in Eire.)