Leatherjacket Nematodes, Protect Your Lawn from Crane Fly Larvae
If your lawn has developed yellowing patches, turf that lifts easily from the soil, or you've noticed starlings and crows persistently pecking at the grass, leatherjackets are the likely culprit. These grey-brown, legless larvae are the underground stage of the crane fly (daddy-long-legs), and they feed on grass roots through autumn, winter, and into spring, often causing the worst visible damage just as the growing season begins.
The life cycle is the key to effective control. Adult crane flies emerge from late July through to September and lay eggs in the turf within 24 hours of hatching. Those eggs hatch within two weeks, and the newly emerged larvae are small, active, and highly vulnerable to nematodes. This is your treatment window. By late spring the larvae have grown considerably and are approaching pupation, at that size, nematodes struggle to kill them. Timing your application to late August through October, when larvae are freshly hatched and soil is still warm, gives you the best possible result.
A spring treatment in April is also worthwhile if you missed the autumn window or have a persistent infestation. Apply at double strength in spring, as mature leatherjackets are significantly harder to kill than newly hatched larvae.
