6 DIY Treatments to Get Rid of Leatherjacket Larvae in Lawns

Leatherjackets are one of the more frustrating lawn pests in UK gardens. They are the larvae of crane flies, often called daddy longlegs, and they feed on grass roots beneath the surface. A small number is not usually a problem, but a heavy infestation can leave yellow patches, weak turf, bare areas and loose grass that lifts away from the soil.

The difficulty with leatherjackets is that most of the damage happens below ground before you notice the problem. By the time birds are pecking at the lawn or patches are turning brown, the larvae may already have been feeding for some time.

The good news is that leatherjackets can often be managed with good lawn care, biological control, bird-friendly gardening and simple monitoring. This guide explains how to identify leatherjacket damage, when to treat the lawn, what DIY methods can help and how to repair affected grass afterwards.

What are leatherjackets?

Leatherjackets are the larvae of crane flies. Adult crane flies are the long-legged insects often seen flying around lawns and outdoor lights in late summer and autumn. They do not cause the lawn damage themselves. The problem starts after they lay eggs in grass.

Once the eggs hatch, the larvae live in the soil and feed on grass roots and lower stems. They are usually grey-brown, legless, tough-skinned and slightly wrinkled. They can be difficult to spot unless you inspect the soil or bring them to the surface.

Leatherjackets are most damaging when there are enough of them to weaken the root system. The grass then struggles to take up water and nutrients, which leads to yellowing, thinning and bare patches.

What does leatherjacket damage look like?

Leatherjacket damage can look similar to other lawn problems, so it is worth checking carefully before treating.

Common signs include:

• Yellow or brown patches in the lawn
• Grass that lifts easily because roots have been eaten
• Thin or weak turf
• Bare patches where grass has died back
• Birds pecking repeatedly at the lawn
• Increased activity from starlings, blackbirds, crows or magpies
• Visible grey-brown larvae in the soil
• Patches that worsen through autumn, winter or spring

Birds feeding on the lawn can be a useful clue. They may be pulling leatherjackets from the turf. However, bird activity alone does not prove leatherjackets are present, as birds also feed on worms and other insects.

Check that leatherjackets are the cause

Before treating the lawn, check whether leatherjackets are actually present. Yellow grass can also be caused by drought, compacted soil, poor drainage, fungal disease, dog urine, poor mowing, nutrient deficiency or chafer grubs.

To check for leatherjackets, inspect the edge of a damaged patch. Lift a small section of turf or dig into the top few centimetres of soil and look for grey-brown, legless larvae. They may curl slightly when disturbed.

You can also use a simple surface test. Water a suspicious patch in the evening, cover it with dark plastic or a damp sack overnight, then check underneath in the morning. Leatherjackets may come towards the surface in the damp, dark conditions.

If you cannot find larvae, do not assume leatherjackets are the problem. Treating the wrong issue wastes time and may delay the right lawn repair.

When do leatherjackets damage lawns?

Leatherjacket problems often begin after adult crane flies lay eggs in late summer or autumn. The larvae then feed through autumn and may continue into winter and spring, depending on conditions.

Damage is often noticed when the lawn is already under stress. Wet weather, mild conditions and weak turf can make the problem more obvious. Spring damage can be particularly frustrating because the lawn may look poor just as the growing season begins.

Treatment timing matters. Biological controls such as nematodes work best when larvae are present and soil conditions are suitable. General lawn care helps most when done regularly rather than only after damage appears.

Encourage birds and natural predators

Birds are natural predators of leatherjackets. Starlings, blackbirds, thrushes, crows and magpies may all feed on larvae in lawns. Encouraging birds can help reduce pest numbers as part of a natural control approach.

Ways to support birds include:

• Providing clean bird baths
• Adding shrubs and trees for cover
• Planting berrying shrubs where suitable
• Avoiding unnecessary pesticide use
• Keeping some natural planting around the garden
• Maintaining safe feeding areas

Birds may also peck at the lawn while feeding. This can look messy, but it may show they are removing larvae. If the lawn is already weak, bird activity can make the surface damage look worse for a while. Once the pest problem is reduced, the lawn can usually be repaired.

Use nematodes for biological control

Nematodes are one of the most useful biological controls for leatherjackets. They are microscopic organisms applied to the lawn with water. Once in the soil, they seek out the larvae and help reduce the infestation.

Nematodes are often favoured because they are a biological treatment rather than a harsh chemical approach. They are commonly used by gardeners who want a more wildlife-conscious way to manage lawn pests.

For best results, nematodes need the right conditions. The soil should be moist, the temperature should be suitable for the product being used and the larvae need to be present. Always follow the instructions supplied with the nematodes, as timing and application can vary by product.

How to apply nematodes

Application is usually straightforward, but accuracy matters. Nematodes are living organisms, so they need to be stored, mixed and applied correctly.

General application steps include:

• Read the product instructions before starting
• Apply when soil temperature and moisture are suitable
• Water the lawn before application if it is dry
• Mix the nematodes as directed
• Apply evenly with a watering can or suitable applicator
• Water the lawn afterwards if instructed
• Keep the soil moist for the recommended period
• Avoid applying in strong sun or dry conditions

The lawn should not be allowed to dry out immediately after treatment. Dry soil reduces the effectiveness of the nematodes.

Use the black plastic method

The black plastic method is a simple DIY way to monitor and reduce leatherjackets in smaller areas. It works by creating damp, dark conditions that encourage larvae to move towards the surface.

To try it:

• Water the affected area in the evening
• Cover it with black plastic, a damp sack or similar dark covering
• Leave it overnight
• Lift the cover in the morning
• Collect visible larvae by hand or allow birds to feed

This method is most practical for small lawns or isolated patches. It will not usually remove every leatherjacket, but it can help confirm the problem and reduce numbers in targeted areas.

Do not leave plastic down for long periods, as it can damage the grass by blocking light and airflow.

Try a soapy water test carefully

A mild soapy water solution is sometimes used to bring leatherjackets to the surface. The solution irritates the larvae, making them easier to spot and remove.

This method should be used carefully and sparingly. Too strong a solution can stress the grass or affect soil life. Avoid using harsh detergents, bleach, disinfectants or cleaning products.

If you try this method, test a small patch first and rinse the area afterwards. It is better for diagnosis and small areas than as a full lawn treatment.

Aerate compacted lawns

Compacted lawns are more likely to struggle with pest damage because roots are already under stress. Aeration improves airflow, drainage and root growth, helping the grass recover more strongly.

Aeration is especially useful if the lawn feels hard, holds water or is heavily used by children, pets or foot traffic.

For small lawns, a garden fork may be enough. Larger lawns may benefit from a hollow-tine aerator or mechanical aeration.

A healthier lawn is not immune to leatherjackets, but it is better able to recover from moderate damage.

Improve drainage

Leatherjackets are often associated with damp lawns. Poor drainage can also weaken grass, making damage worse.

Signs of poor drainage include:

• Water sitting on the surface
• Moss growth
• Soft, muddy patches
• Thin grass in low areas
• Compacted soil
• Persistent dampness after rain

Improving drainage may involve aeration, scarifying, top dressing, reducing compaction, improving soil structure or installing a more formal garden drainage system in severe cases.

Drainage work will not kill leatherjackets directly, but it can make the lawn less favourable and improve recovery.

Scarify and remove thatch where needed

Thatch is the layer of dead grass, moss and organic material that can build up at the base of the lawn. A small amount is normal, but too much can hold moisture and weaken grass growth.

Scarifying removes excess thatch and opens the lawn surface. This can improve air movement, reduce moss and help new grass establish.

Do not scarify a severely weakened lawn too aggressively. If the grass is already thin from leatherjacket damage, heavy scarifying can make it look worse temporarily. Time the work for when the lawn is actively growing and able to recover.

Maintain a healthy mowing routine

Mowing affects lawn strength. Cutting too short weakens grass and makes it more vulnerable to stress, pests and drought.

For a healthier lawn:

• Mow regularly during the growing season
• Avoid scalping the grass
• Raise the cutting height during dry weather
• Keep mower blades sharp
• Do not mow waterlogged grass
• Remove heavy clippings if they smother the lawn

A dense lawn with a strong root system is better able to withstand leatherjacket feeding than a weak, scalped lawn.

Water sensibly

Leatherjackets and weak lawns both thrive in different ways when watering is poor. Constantly wet soil can favour larvae and moss, while drought-stressed grass is less able to recover from root damage.

Water newly seeded or repaired areas carefully, but avoid keeping established lawns permanently wet. Deep, occasional watering during dry periods is usually better than constant light watering.

If the lawn stays wet even without watering, look at drainage and compaction rather than adding more water.

Feed the lawn appropriately

A balanced lawn feeding programme can help grass recover from leatherjacket damage. The aim is strong, steady growth, not soft, excessive growth.

Use a lawn feed suitable for the season and follow the instructions. Overfeeding, especially with unsuitable fertiliser, can stress the lawn and create weak, lush growth that is more vulnerable to problems.

Feeding alone will not solve leatherjackets, but it can support recovery once the larvae are controlled.

Overseed thin areas

Leatherjacket damage often leaves thin patches where weeds and moss can move in. Overseeding helps thicken the lawn and restore bare areas.

For best results:

• Remove loose dead grass
• Lightly rake the surface
• Improve soil contact
• Sow a suitable grass seed mix
• Cover lightly with top dressing if needed
• Water gently
• Protect from birds and foot traffic
• Keep moist until established

Only overseed once the main leatherjacket problem is under control. Otherwise, new roots may be damaged again.

Repair bare patches

Bare patches should be repaired promptly once the pest pressure has reduced. Leaving soil exposed allows weeds and moss to establish.

Patch repair is usually simple:

• Remove dead grass and loose debris
• Break up compacted surface soil
• Add topsoil or lawn dressing if needed
• Level the area
• Sow grass seed
• Firm gently
• Water carefully
• Keep pets and people off until established

If the soil has become uneven because birds have pecked at the surface, level it before reseeding.

Do not ignore bird damage

Birds often reveal leatherjacket problems by pecking at the lawn. However, repeated pecking can also make the lawn look worse.

Rather than trying to scare birds away immediately, check why they are feeding. If they are finding leatherjackets, they are helping remove the pest. Once larvae numbers fall, bird activity usually reduces.

If birds are damaging newly seeded areas, protect the repaired patches with suitable netting or fleece, making sure it is secure and does not trap wildlife.

Avoid harsh chemical shortcuts

Many gardeners look for a quick chemical fix when leatherjackets appear. However, products available to home gardeners can change, and some older lawn pest controls are no longer available for domestic use.

Use only products that are approved for the intended use and follow the label exactly. Do not apply agricultural, professional or improvised chemicals to a domestic lawn.

A safer long-term approach is usually to combine biological control, monitoring and good lawn care.

Prevent future leatherjacket problems

You may not be able to prevent every crane fly from laying eggs, but you can reduce the risk of severe damage.

Prevention steps include:

• Keep the lawn healthy and dense
• Avoid long-term waterlogging
• Improve drainage and aeration
• Reduce excessive thatch
• Monitor crane fly activity in late summer and autumn
• Check the lawn if birds begin pecking repeatedly
• Apply nematodes at the right time if needed
• Repair thin areas before they worsen

Leatherjacket control is easier when problems are spotted early.

Leatherjackets in new lawns

New lawns can be vulnerable because the roots are not fully established. If leatherjackets feed on a new lawn, the grass may lift or fail to knit into the soil properly.

If you are creating a new lawn in an area with known leatherjacket problems, monitor closely in the first autumn and spring. Keep the lawn healthy, but avoid overwatering and poor drainage.

Protecting new turf or seed from birds may also be needed if they start searching for larvae.

Leatherjackets and artificial grass

Leatherjackets feed on living grass roots, so they are not a lawn pest in the same way under artificial grass. However, the soil beneath and surrounding areas may still contain insects.

If replacing a lawn with artificial grass because of pests, think carefully. Artificial grass brings its own maintenance, drainage and heat considerations. It is usually better to solve the underlying lawn health and pest issue where possible.

Leatherjackets and garden design

Garden layout can affect lawn health. A lawn surrounded by dense shade, poor drainage and heavy foot traffic will be more vulnerable to pest damage and slow recovery.

To support a healthier garden:

• Improve airflow around the lawn
• Keep fence lines and hedges managed
• Use paths for heavy traffic routes
• Choose planting suited to the site
• Use borders where grass struggles under shade
• Address drainage before repeatedly reseeding

If a lawn repeatedly fails in the same spot, the problem may be the site conditions rather than leatherjackets alone.

Fencing, birds and lawn pests

Garden boundaries can influence wildlife activity. Fence panels, hedges, trellis panels and shrubs provide perches and cover for birds that feed on lawn pests. A wildlife-friendly boundary can help encourage natural pest control.

At the same time, dense planting along fence lines should be managed so it does not trap excessive damp over the lawn. Good airflow helps grass stay healthier.

A balanced garden can support birds and beneficial wildlife while still keeping the lawn tidy and usable.

Common mistakes when treating leatherjackets

Leatherjacket problems are often made worse by treating symptoms rather than causes.

Common mistakes include:

• Assuming every yellow patch is leatherjacket damage
• Applying treatments without checking for larvae
• Using nematodes when soil is too cold or dry
• Letting the lawn dry out after nematode application
• Scalping the lawn with low mowing
• Overwatering already damp ground
• Ignoring compaction and drainage
• Repairing bare patches before controlling larvae
• Using unsuitable chemicals
• Failing to monitor again in autumn and spring

Good identification and timing are essential.

Leatherjacket treatment checklist

Use this checklist if you suspect leatherjackets in your lawn:

• Check whether the damage matches leatherjacket symptoms
• Lift a small section of turf to look for larvae
• Use the black plastic method if needed
• Encourage birds and natural predators
• Apply nematodes when conditions are suitable
• Keep the soil moist after nematode treatment
• Aerate compacted areas
• Improve drainage where needed
• Avoid cutting the lawn too short
• Remove excess thatch if appropriate
• Repair bare patches once larvae are controlled
• Overseed thin areas
• Monitor again during likely problem periods

Frequently asked questions

What are leatherjackets?

Leatherjackets are crane fly larvae. They live in the soil and feed on grass roots, which can cause yellow patches, weak turf and bare areas in lawns.

How do I know if my lawn has leatherjackets?

Look for yellow patches, weak grass that lifts easily, bird pecking and grey-brown legless larvae in the soil. Lift a small section of turf at the edge of a damaged patch to check.

When is the best time to treat leatherjackets?

Treatment depends on the method. Nematodes need suitable soil temperature and moisture and should be used when larvae are present. Always follow the product instructions for timing.

Do nematodes work on leatherjackets?

Nematodes can be effective when applied correctly in suitable conditions. The soil needs to be moist and warm enough for the specific product being used.

Are nematodes safe for lawns?

Nematodes sold for lawn pest control are designed for use on lawns. Follow the instructions carefully and keep the soil moist after application.

Can birds help control leatherjackets?

Yes. Birds such as starlings, blackbirds and thrushes may feed on leatherjackets. Bird activity can help reduce larvae numbers, although pecking may temporarily make the lawn look messy.

Will soapy water get rid of leatherjackets?

A mild soapy water solution may bring some larvae to the surface, but it is better used for checking and small areas rather than as a complete control method. Avoid harsh detergents or strong mixtures.

Can leatherjacket damage recover?

Yes, many lawns recover once the larvae are controlled and the grass is repaired. Bare patches may need reseeding, top dressing and careful watering.

Do leatherjackets come back every year?

They can return if adult crane flies lay eggs in the lawn and conditions suit the larvae. Regular monitoring, healthy lawn care and timely treatment reduce the risk of severe damage.

Should I replace my lawn if I have leatherjackets?

Usually no. Most leatherjacket problems can be managed with treatment and lawn repair. Replacement may be considered only if the lawn is very badly damaged or has deeper issues such as poor drainage and compaction.

Final thoughts

Leatherjackets can cause noticeable lawn damage, but they are manageable if you identify the problem early and use the right methods. Birds, nematodes, monitoring, aeration, drainage improvement and good lawn care all have a role.

The best approach is not to rely on one quick fix. Confirm that leatherjackets are present, treat them when conditions are suitable, then help the lawn recover with overseeding, patch repair and improved maintenance.

A strong, healthy lawn is more resilient against pests. By improving drainage, avoiding overwatering, mowing sensibly and repairing thin areas promptly, you can reduce the impact of leatherjackets and keep your garden looking greener through the year.