The Problem with Leatherjackets

Crane fly larvae, commonly referred to as leatherjackets, dwell in the upper layers of soil, where they feed on grassroots and plant material. Their presence is most problematic in transition months, and their activity can lead to spongy ground and deteriorating turf condition. Public lawns may become difficult to maintain without proper control.

Detecting Larval Activity Quickly

Identifying larvae before serious damage occurs is beneficial. Watch for signs such as increased bird activity, thinned areas, and irregular surface wear. Cut small patches in the turf to detect larvae beneath. Conducting these checks during early spring helps with timely responses.

Seasonal Risks to Grass Condition

Leatherjackets can remain active underground during milder winter spells. If they are not monitored, the turf’s ability to recover in spring is delayed. Maintenance scheduling based on weather conditions helps reduce pressure on affected areas.

Physical and Mechanical Solutions

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

Biological Pest Control

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

Responsible Chemical Use

In some cases—especially on frequently used surfaces—chemical treatment may be necessary. Authorised turf protection products may be applied, but only according to current regulations. Blending chemical input with cultural and biological steps prevents overuse.

Reducing Future Risk

To avoid outbreaks in future seasons, aim to optimise drainage, encourage strong rooting, and maintain steady nutrient levels. Monitoring turf after crane fly emergence in late summer offers insight into larval activity levels for the months ahead.

Frequently Asked Questions

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



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



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


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• 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 requires a mix of early detection, well-timed treatment, and varied management strategies. By combining physical methods, biological control, and limited chemical use, turf conditions can be protected throughout the year.

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