The Problem with Leatherjackets

Crane fly larvae, commonly referred to as leatherjackets, dwell in the upper layers of soil, where they damage grassroots and decaying material. Their presence is most problematic in transition months, and their activity can lead to fragile ground and poor turf condition. Public lawns may become unusable without proper control.

Recognising Early Signs

Identifying larvae before serious damage occurs is essential. Watch for signs such as increased bird activity, thinned areas, and irregular surface wear. Cut test squares in the turf to detect larvae beneath. Conducting these checks during late winter supports better planning.

How the Seasons Influence Turf Health

Leatherjackets can continue feeding underground during milder winter spells. If they are not kept in check, the turf’s ability to recover in spring is hindered. Maintenance scheduling based on weather conditions helps reduce pressure on affected areas.

Cultural Turf Management

Groundskeepers often begin with physical practices. Regular aeration strengthens root growth and improves turf firmness. Raising mowing height during feeding periods can improve resilience, and rolling moist turf may lift larvae, leaving them open to natural predation. These approaches help improve turf quality, even if they do not eradicate the pests.

Natural Solutions

Nematodes, microscopic bioagents, offer a natural way to address larvae. They are most effective when applied during early autumn, under suitable moisture and temperature conditions. When timed and applied correctly, they reduce larval numbers and allow the turf to stabilise.

Supplementing with Registered Products

In some cases—especially on high-demand surfaces—chemical treatment may be necessary. Registered turf protection products may be applied, but only according to label instructions. Blending chemical input with cultural and biological steps preserves soil health.

Avoiding Repeat Infestations

To avoid outbreaks in future seasons, aim to improve drainage, support strong rooting, and maintain balanced nutrient levels. Monitoring turf after crane fly emergence in late summer helps predict larval activity levels for the months ahead.

Frequently Asked Questions

• When do leatherjackets feed the most?
  
  They tend to be feeding in greater numbers during mild periods in autumn and spring.



• How can I be sure I have a problem?
  
  Cut out a small patch of turf and count the number of larvae beneath. This provides a direct population check.



• Can nematodes survive in cold soil?
  
  No. They require specific temperatures and soil moisture to be effective.



• Does mowing height matter?
  
  Yes. Leaving grass slightly longer during larval feeding helps support plant health.



• Why are birds damaging my lawn?
  
  Birds often scratch where larvae are present. Their behaviour can be an unintended clue of infestation.

Main Takeaway

Managing crane fly larvae benefits from a blend of early detection, well-timed treatment, and varied management strategies. By coordinating physical methods, biological control, and limited chemical use, turf conditions can be maintained throughout the year.

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