Information about satin moth (Leucoma salicis), a forest defoliating insect found in Ontario.
- Invasive – native to Europe and Asia.
- The satin moth is an invasive pest from Europe and western Asia that was first detected in eastern Canada in the Maritime provinces in 1930.
- Satin moth was first found in eastern Ontario in 1972, but is now found across the southern portion of the province; populations also exist around Sudbury and Sault Ste. Marie.
- Satin moth originally was mainly found on European ornamental trees, but it is increasingly attacking and defoliating native tree species.
“Invasive” refers to a species that has moved outside of its native habitat and threatens the new environment, economy or society by disrupting local ecosystems.
The satin moth will feed on all poplar species (Populus), including ornamental varieties such as European poplar (Populus tremula). It can also be found on willow (Salix).
Species identification and life cycle
- Over-wintering larvae emerge in mid May.
- Young larvae first feed on the surface of leaves and eventually consume the entire leaf with the exception of the major veins.
- In early July, larvae spin cocoons in between leaves and then pupate.
- Pupae are shiny black with gold and white hairs.
- Full grown larvae are 30-45 mm long with a black head, black body and a line of yellow spots edged in white with hairy reddish tubercles.
- Moths have satiny white wings with a wing span of mm; the head, thorax and abdomen are black, but are so densely clothed with white hair they appear white.
- Oval clusters of 150-200 eggs are laid on the main stem and branches of the tree; eggs are green in a cluster and covered with a foamy white secretion; eggs hatch in July and August.
Symptoms and damage
- Trees infested with satin moth can be completely stripped of foliage.
- Severe defoliation can cause growth loss and some branch mortality.
- Pupal cases can be seen on trees.
- In mid- to late July, white shiny moths can be observed flying around trees.
Satin moths have natural predators such as birds, wasps, beetles and the cytoplasmic-polyhedrosis virus. Chemical insecticides could also be used for effective control.