Gypsy Moths, specifically the European Gypsy moth EGM (Lymantria dispar dispar),  threaten our trees and forests in south-western Ontario. We homeowners and gardeners need to know how to recognize and deal with this nasty pest which can completely defoliate and kill our trees!

First – Understand the Characteristics and Life cycle of the Gypsy Moth

Gypsy moth larva

  • Overwinters in the egg stage often on the bark of trees
  • In Spring, eggs hatch and larvae ascend the trees to feed on the new foliage
  • Initially, feeding occurs during the day, but as the caterpillars mature, feeding occurs mainly at night- often this can delay the detection of infestations.
  • Mature larvae are 50mm long, dark-coloured, hairy, with a double row of five pairs of blue spots, followed by a double row of six pairs of red spots, down the back.
  • Feeding is complete in July
  • Male moths are light brown and slender-bodied, while females are white and heavy-bodied

Infographic on the gypsy moth lifecycle. For more information on this infographic please contact forestry@london.ca

Second – Plan your attack to reduce the destruction caused by this pest

1- Remove and destroy egg masses in winter to reduce the number of hatched caterpillars in spring. 

gypsy moth egg masses

Gypsy Moth Egg Masses

2 – Trap and destroy moths in summer to reduce the number who can breed and start the egg-laying cycle again. Methods include Burlap Banding, Hand-picking, Pesticide use, and Trapping. Read More about each method  – City Of London Gypsy Moth advisory.

Gypsy Moths threaten our trees – Upper Thames Conservation YouTube video – How to remove egg masses

More resources:

Upper Thames Conservation Authority issues warning

Gypsy Moths – Ontario’s Invading Species Awareness

Middlesex Centre – Gypsy Moth Outbreak