A healthy lawn can quickly decline if the leather jacket grub, the larvae of crane flies, take hold. These pests damage grass by feeding on the roots, leading to thinning, yellowing and bare patches. If you’ve noticed increased bird activity or bare and weak grass that pulls up easily, leatherjackets may be the cause. Here’s how to identify, test for, and treat them effectively.
Symptoms of Leather jacket Damage
- Bare soil – Patches where grass has died back completely
- Yellowing patches – A sign of stressed or dying grass
- Thinning grass – Especially in shady areas where turf struggles to recover
- Holes in the lawn – Birds, such as starlings and crows, pecking at the turf in search of grubs
- Increased bird activity – Birds feeding on the lawn can be a sign of an infestation
- Weak grass plants – Easily pulled from the ground with little resistance
- Separated leaves – Grass leaves detach easily from the roots
How to Identify Leatherjackets
To confirm an infestation, lift a section of turf and check the top layers of soil for leatherjacket grubs. They are greyish-brown, worm-like larvae without legs.
How to Test for Leatherjackets
A simple test involves covering a small patch of lawn with a damp tarp overnight. Leatherjackets are attracted to the dark, moist environment and will surface by morning, allowing you to assess the population.
Recovery Plan
- Regular Feeding
Maintain a strong, resilient lawn with seasonal fertiliser applications. - Spring Nematode Treatment
Apply nematodes at double the standard rate in early spring when soil temperatures reach 10°C. Water them in thoroughly and continue watering for 2-3 weeks to ensure they penetrate the soil and target the grubs. - Aeration & Overseeding
Improve root development and lawn recovery by aerating and overseeding in the spring. For best results, use a high-quality seed mix such as Green Velvet All Rounder and consider covering newly seeded areas with horticultural fleece for better germination. - Autumn Professional Treatment
In late September or early October, repeat nematode treatment alongside a licensed professional chemical control. Greener Gardens is authorised to apply this treatment. Its application is limited to once per year and trials have shown that autumn application is the most effective time for application.
Additional Resources
By following these steps, you can restore your lawn’s health and protect it from future infestations. If you need further assistance, Greener Gardens is here to help!