Lymantria dispar

Lepidoptera: Lymantriidae

Identification
• Caterpillars are dark and hairy with 2 indistinct rows of blue and red dots on the back. (a) They grow to 2".
• Male moths have a 1¹/₂-2" wingspan and are dark brown with black markings. (b)
• Female moths have a 2" wingspan and have whitish wings with black markings. (c)
• Eggs are laid in a 1" oval mass that is covered with the tan body hairs of the female. (c)

Damage
• Caterpillars begin feeding on the leaves and defoliate oak, maple, spruce, and many other trees in the spring.
• The caterpillars can become very numerous and kill trees by defoliating them several years in succession.

 Management
• Spray caterpillars with bacterial insecticides if in a generally infested area after oak leaves expand in spring.
• Contact your local extension or Department of Agriculture office if not in a generally infested area.
• Remove egg masses and destroy them.
• Triangular green or orange pheromone traps are used for surveillance. Do not damage or move the traps.