This week (September 2013) I have seen a great deal of crane fly larvae (tipulidae) emerging from lawns and taking flight, ready to clumsily annoy us when we least expect it.
It seems that the very wet summer of 2012 meant that these gangly beasts largely escaped predation and had plenty of opportunity to lay thousands of eggs in damp lawns all over the country.
After a year of the fat larvae munching their way through grass roots they pushed their way to the surface over the past few weeks and pupated, leaving the brown larvae skins on the surface of lawns.
These skins look like insects, but closer inspection reveals that they are hollow and brittle. They are just an indication of the young insect that they used to contain.
Once the crane fly has flown, they spend their last days trying to find a mate before laying eggs in the grass and dying.
These eggs sit in the lawn for several months before hatching into leatherjacket grubs, and its these grubs which over-winter, munching through the roots of your lawn.
How do I prevent crane fly larvae damaging my lawn?
Earlier this year I published an article explaining how you can prevent crane fly larvae (or leatherjackets) from destroying your lawn, and my advice hasn’t changed during the year.
What I have seen is that some lawns do seem to be more susceptible to leatherjacket attacks than others. You should be especially wary if you are the only lawn in your area, or own a lawn in a more urban environment, as these seem to experience more concentrated attacks. This will be because the adults will all try to pick the same patch of grass in which to lay their eggs, giving rise to a potentially huge population of grubs in a small area. This is when the problem of lawn damage is generally most noticeable, but all lawns do run a slight risk.
If you do find your lawn is damaged by leatherjackets, have a look at steps you should take to bring your lawn back to it’s best.
If you are at all worried about the crane flies laying eggs in your lawn. Unfortunately chemical controls for leatherjackets are all removed from the market. Please get in touch to discuss alternatives.
Kris Lord
Further reading about crane flys and leatherjackets
- Royal Horticultural Society – Leatherjackets
- BBC Gardening – Leatherjackets
- RSPB
Great article. I was wondering why I was seeing so many of these, as you say, clumsily flying towards me while I was attempting to do work! I can stop my paranoid thoughts of my lizard food secretly being crane fly larvae now.
Thanks for the info 🙂