Identify and report sightings of gypsy moth (Lymantria dispar)
The gypsy moth (Lymantria dispar) is an important defoliator of a wide range of trees and shrubs in mainland Europe, where it periodically reaches outbreak numbers. The British form of the moth became extinct in the early 1900s and it was unknown here until a small colony was discovered in northeast London in 1995. Since then isolated breeding colonies have also been found in Buckinghamshire and Dorset. It is likely that moth eggs from mainland Europe were carried to these locations on vehicles, wooden packaging or imported timber.
This page will help you to identify L. dispar and its life cycle stages.
- Full grown larvae (caterpillars) can be up to 70mm long
- Voracious appetite
- Feeds on leaves of broadleaf tree and shrub species
- Feeds on conifers when food is in short supply
- Extensive damage to foliage
- Repeated deforestation can cause tree death (single deforestation causes conifer death)
Insect Life Cycle
- Larvae hatch in spring and are dispersed on silk threads in the wind
- Fully grown caterpillars develop into adult moths in mid to late summer
- Adult male moths are attracted to females by chemical scents
- Adult females lay 50-800 eggs in clusters
If you suspect a Gypsy moth colony, you should report the sighting to Forest Research’s Tree Health and Diagnostic Advisory Service.
Forest Research has used pheromones to monitor this insect in the past in London and Aylesbury, but we no longer carry out regular surveys. We know gypsy moth is now widely spread across most of London and that a much smaller, more discrete colony persists in Aylesbury.