Mission: pest controllers

How to take part

Download the fully illustrated instructions [pdf]

Download the insect identification guide [pdf]

If you are very keen and have access to a good microscope you could try identifying the species of parasitoid with the parasitoid species identification guide [pdf]


  • Make sure that your leaf is infected with the alien leaf-mining moth otherwise you won't find anything. (Check out the difference between the leaf-miner and the leaf blotch fungus.)
  • Pick the leaves and check for insects on the correct dates otherwise you may get no insects. However, you could also try this mission with leaves picked in the autumn.
  • Identify the insects as accurately as you can. Make sure you don't count empty pupal cases or other insects by referring to the insect identification sheet.

Although in previous years we collected the results from this mission, we are not collecting them any more. However, do feel free to let us know if you took part and how you got on. Compare your results with the summaries of the results below.

About this mission

  • The purpose of this mission is to understand how likely the alien moths are to be attacked and killed by their natural pest controllers. We expected more wasps to be attacking the moths in places were moths have been present for longer. 
  • These natural pest controllers are parasitic wasps which are vital in controlling numbers of many insects. Don’t worry though, these wasps do not harm people.
  • Records of leaves from which no insects emerged or only adult moths emerged are just as important as records of pest controllers.
  • Studies elsewhere in Europe found only 1 in 10 alien moths were killed by the pest controllers. Is it more or less in Britain? Your data has helped us find this out.