Mission: pest controllers

Discover how many alien moths have been killed by pest controllers in your leaf, by recording which insects hatch from it.

From 2010 to 2013 we collected the results of this mission as part of a real science. From now on we are not collecting the results, but we have left the information here particualrly for school teachers who want to do the project with their class (it is ideal for key stages 2, 3 and 4 and fits into the school term in England & Wales) and naturalists who wish to discover more about parasitoids.

All you need is:

  • an infected conker tree
  • a 'zip-lock' bag
  • a magnifying glass or eye lens
  • a few minutes in early July to collect a leaf
  • a few minutes in late July to record your results

Your mission in brief:

  • Find your infected conker tree (see here for help with tree identification).  Record any information you will need to find the tree on a map.  
  • During the first week of July, pick a leaf that is within your reach; choose from it one leaflet (a ‘finger’ of the hand-like leaf).
  • Record the number of leaf mines (whitish blotches) in the leaf.
  • Seal your leaf in a 'zip-lock' bag. 
  • Wait until late July, then count and identify the tiny insects that emerge – are they alien moths, pest controllers, or other insects, like aphids?  If you can see one pest controller, that means one alien moth has been killed by it!

Download detailed instructions

Download insect identification guide

To take part in Conker Tree Science, all you need to do is identify insects as alien moths, pest controllers and others with the insect identification guide.

However, we have also produced an illustrated guide to the different species of pest controller [1.6Mb]. Identifying the different species is optional and for those who like a challenge. You will need a good quality binocular microscope.

A pest-controlling wasp (photo: Brian Valentine)
Tiny Eulophid wasps like this one, only 1.85mm long, may be attacking the alien moths in your leaf   
(photo: Brian Valentine)

The alien leaf-mining moth (photo: Paul Kitchener)
An adult alien moth (photo: Paul Kitchener)

Another pest controller (photo: Brian Valentine)
The pest controllers are shiny, with transparent wings
(photo: Brian Valentine)