Its a hard thing to be focusing on now, with the heatwave and drought stress to be dealing with, along with planning for renovations. Crane fly are probably as close to the bottom of the problem list that they ever get, at this time of year. Having spent all season fattening up on much loved turf and roots many are starting to think (if they do think – jury’s out on that one) about easing off feeding and pupating ready to become adults.
So its a time when you will be seeing least pressure from leatherjacket feeding, especially if you’ve had a bit of rain and are getting good growth to mask any damage, and a time we are asking you to be extra vigilant in watching for and logging adult Crane fly sightings in PestTracker please.
It’s not clear exactly what tells a leatherjacket ‘its time‘ is it the call of wild? or something more tangible? Like all insects they are cold blooded, so at the mercy of ambient conditions, generally this means the warmer it is the faster they can feed up ready for the next stage of life.
With flies, anyone who has been fishing will know that if you keep maggots in the fridge they will last a long time, leave them out of the fridge in the summer; in the back of the car for example, and they will quickly pupate and emerge as flies.
So, on the face of it we would expect in a hot year like this one, to see an earlier emergence of Cranefly. As with all things that would be too easy. Very warm dry conditions can affect insect pests in the same way it affects grass, they may shut down to preserve water in extreme conditions, meaning feeding may actually be delayed. Additionally, and unlike flies, Crane fly only have one life cycle a year (house flies will go through multiple generations temperature permitting).
To make sure they all fly at a similar time, so everyone can find a mate (and so make headaches for as many turf professions as possible) they must be taking cues from something else, like when swallows know when to migrate back to Africa, it could be on day length, shifts in magnetic fields or other uncategorised ‘bird senses’.
You can see from Glenn’s Cranefly emergence tracker from previous years that the North generally see’s emergence first suggesting it could be the onset of cooler temperatures that trigger the mass exodus.
Whether the peak flight is earlier or later than what we might expect, we will only know from the logging of sightings that you are doing, so keep your eyes peeled and log what you see.
Perhaps 40C was just too hot and we won’t see any this year, the leatherjacket craze could be over?
