Know your insect friends

Learn to distinguish the insect pests that eat your plants from the insect predators that eat the pests, then do what you can to encourage the predators. Insecticides do not always differentiate and, while hitting the immediate problem, can easily create a bigger problem in the future.

Ground dwellers

Ground and rove beetles
  • important slug predators;
  • also eat root fly eggs and larvae.
Centipedes (good)
  • 15-83 segments, fast-moving with 1 pair legs/segment;
  • nocturnal hunters, eating slugs, snails, etc.
  • need daytime refuges.
Don't confuse with millipedes (bad)
  • slower; 2 leg pairs/segment;
  • feed on plant matter.

Flying corps

Anthocorid bugs
  • 3-5 mm, reddish-brown to dark brown;
  • eat mainly greenfly, also other pests;
  • need trees and hedgerows for shelter and food.
  • 100 species in Britain, active summer/autumn;
  • many mimic bees or wasps for self-protection but they have no sting and a less well-defined 'waist';
  • larvae do the good work, eating 100s of greenfly mainly at night.
  • three types: green, brown and powdery;
  • larvae eat greenfly, also scale insects, caterpillars, mites;
  • adults feed on nectar.
  • larvae eat mainly greenfly, active May-July;
  • adults overwinter in undergrowth, cracks, etc.
Parasitic wasps
  • young live on young stages of other insects;
  • larger adults prey on caterpillars, smaller on aphids, scale insects.

Drawing by Richard Allen