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Field guide to exotic pests and diseases: Nun moth
Lymantria monacha (Linnaeus)
Nun moth caterpillar
Source: USDA
Nun moth male, dark form
Source: USDA
Identification: eggs orange-brown, spherical, and laid in clumps without covering of scales. Larvae 30-40mm long; have dark grey, tan or green coloured bodies, orange heads with black freckles. Adults have white forewings with dark lines and patches; occasionally dark brown to black colour form occurs. Females have a pointed reddish abdomen with black spots and a 45-55mm wingspan; males 35-45mm wingspan.
Hosts: larvae feed on the foliage of ornamental and forest conifers, elm, oak, larch, maple, and fig.
Distribution: Europe, Far Eastern Russia.
Detection:Eggs and larvae: most often found on forest products, shipping containers, cargo and ships’ structures. Eggs are laid randomly; larvae can survive a week without feeding, spin silken threads and spread long distances in the wind.
Adults: strong fliers, attracted to light.
Potential impact: defoliation by larvae can kill trees, causes enormous economic loss.