Leatherjacket lifecycle and application times

There are two main species of leatherjacket in the UK, the larvae of the European Crane Fly and the Marsh Crane Fly.

The European Crane Fly

Tipula paludosa (European crane fly) Leatherjackets have one generation per year*.

The adults emerge from pupation from July to September and almost immediately lay their eggs (peak emergence can vary regionally).

The larvae hatch out after about 14 days and start to feed on the bases of stems and roots immediately (this is when they are most vulnerable to nematodes), they become more active and feed voraciously in the spring when the soil begins to warm (the second opportunity to treat with nematodes but at double strength).  

When fully grown they reach approximately 3-4 cm in length and then stay within their burrows for about 6-8 weeks before making their way to the soil surface to pupate and the cycle repeats. 

*If you are seeing Adult Crane Flies in April/May, see the lifecycle of the Marsh Crane Fly.

The Marsh Crane Fly

Tipula oleracea (Marsh Crane Fly) Leatherjackets have two generations per year.

The adults emerge from pupation from April to May and July to September and almost immediately lay their eggs (peak emergence can vary regionally).

The larvae hatch out after about 14 days and start to feed on the bases of stems and roots immediately (this is when they are most vulnerable to nematodes), when fully grown they reach approximately 3-4 cm in length and then stay within their burrows for about 6-8 weeks before making their way to the soil surface to pupate and the cycle repeats. 

FOR OPTIUMUM RESULTS:

Prior to applying the nematodes:

• Cut the grass short before treatment.
  
• Soil should be between 10°C and 30°C during application and for at least two weeks after.
  
• Irrigate the area to be treated prior to application in order to apply the nematodes to a moist lawn.
  
  

To avoid desiccation of the nematodes:

• Avoid direct sunlight; make applications in the evenings or in dull conditions
• Application during rain is highly desirable.
• It is very important to irrigate immediately after application, water the grass well so the nematodes are washed below the thatch layer into the soil to reach the roots where the larvae will be feeding.
• Ensure soil is moist for at least two weeks after application.