Lymantria dispar dispar (LDD) is an insect native to Europe that has been introduced to North America. They are also known by the name gypsy moth. LDD caterpillars eat leaves from trees during the spring and early summer. This causes trees to lose their leaves.
Healthy trees can grow their leaves back in the same season, but an ongoing LDD infestation weakens trees and can make them more likely to be damaged from other insects.
LDD like to eat the leaves on trees while they are in their caterpillar stage. They strip the leaves until early summer, when they enter their moth stage.
They prefer Oak trees but will eat the leaves of any hardwood tree such as oak, ash, birch or elm. Look for trees with many caterpillars and not a lot of leaf coverage.
The City monitors and controls LDD populations. Each year, priority areas are identified where there are high numbers of LDD. City-owned trees in these areas will receive treatments that may include:
Report sightings of LDD in your neighbourhood using our online reporting form. You can also check other sightings using our interactive map:
You can also use some of these pest control techniques, to help protect trees on your property:
Sign up to receive email updates about tree pest management from the City.
For more information about tree pests, email firstname.lastname@example.org or call 311 (905-615-4311 from outside Mississauga).