New chafer grub trials results for Acelepryn and NemaTrident

Product Update
Chafer bugs

The strategy of a well-timed Acelepryn insecticide, followed by an application of NemaTrident beneficial nematodes has proven to enhance overall control and improve reliability of leatherjacket control programmes. 

Now, the techniques have been shown to deliver the same effects on chafer grubs, with new results of a UK field trial on Forest Pines Golf Club in Lincolnshire. 

Reporting the results Syngenta Technical Manager, Sean Loakes, says: "We’ve got lots of data on the success of Acelepryn followed by Nematrident B (Heterorhabditis bacteriophora nematodes) versus chafer grubs in controlled situations."

"But it’s great to now be able to add a UK field trial on a golf course to get a greater picture of the work in practice." 

Watch the chafer grub trial results discussion

Following treatment last summer, timed as soon as practical after peak egg laying of adult chafer beetles, the trial areas were reassessed this spring for the number of chafer grubs present, and their size.   

The results show a clear trend that confirms the smaller the larvae were at the time of treatment (typically in the first year after hatching) the higher the level of control by the treatments, says Sean.


Grubs which have had more time to build up fat reserves - later instars, probably from previous years of chafer beetle activity, which have had time to grow - were still controlled, but less consistently.

"We also saw the largest grubs, the ones which would be getting ready to become adults later this summer, proved harder to control."

"Depending on the situation and the chafer beetle being targeted - with some species having a one year life cycle, but others up to three years or more - a programmed approach may be necessary year on year for some susceptible areas," he advises.

The trial has also provided valuable insights into application techniques to optimise NemaTrident beneficial nematode success.

Sean's Top Tips for NemTrident B application:  

  • Soil temperatures 12°C+
  • Irrigation or rainfall post application
  • White nozzles
  • Remove filters before spray
  • Soils remaining moist for 2 weeks after spray

Find out more of how to get the best from your NemaTrident applications