Large (up to 7cm long) brownish yellow and black hairy caterpillars, with red and blue markings causing defoliation of large parts of a wide variety of trees or shrubs.
Gypsy moth should not be confused with oak processionary moth, which has dark coloured caterpillars with fine white hairs and is usually only found on oak. Hairs from the gypsy moth do not usually cause as much irritation as those from oak processionary moth.
The caterpillars of gypsy moth are present from April to August and when fully grown pupate on a surface such as the bark of a tree, brick wall or other vertical surface. The pupal stage lasts about two weeks and emerging adult moths are active from July to September. Eggs are laid in clusters of 50-800 on the bark of host plants These clusters are covered in hairs and measure up to 4cm in diameter; the eggs hatch the following spring.
The moth is most prevalent in London and a few surrounding areas. If you should find gypsy moth outside of these areas please report it to Forest Research.