After the heavy rainfall this weekend I had several course managers reporting a late emergence of Cranefly just when they thought it was all over!
The obvious question on there mind was “Do I stick with my Acelepryn timing plans?“
The answer to that is yes.
The more we study the emergence pattern of the Cranefly the more we realise its a very prolonged period, This year the first emergence reported was around the 2nd week of August, with it still going on now in the last week of October.
This is a pattern that has repeated itself since we started logging using PestTracker and I suspect emergence will continue to be reported for another couple of weeks yet.
In total will be around 11 weeks of hatching with a peak in the middle two weeks of September.
It is my belief that this is the reason we see this wide range of ages of leatherjackets in the soil profile. The largest ones would have had an additional 10 weeks of development time which would have all been during mild periods when the young leatherjacket can actively feed due to the high temperatures.
I’ve plotted the last few weeks of reported sightings of emergence on the map below and you can see a similar trend to previous years where the later reports tend to be in the south of the country. The warmer temperatures we see in the south seem to keep them in the soil a little longer.
The user trial we did last year showed better levels of control by delaying application of Acelepryn until one month after peak flight. I suspect these late emergence of the cranefly has something to do with the reduced control we get from the earlier application.
Best timing this year would be somewhere between 3rd week of October and 1st week of November and even though we’re seeing these later emerging cranefly, I’m confident that the later application of Acelepryn will give very high population reductions due to the way Acelepryn works in the soil (blog about that here……..)