What is a LDD?

LDD which was formerly know as European Gypsy Moth, is a non-native defoliating insect that feeds on a variety of tree species found in Centre Wellington and throughout North America. When populations are high, they can eat all the leaves on a tree in a short amount of time. The Township of Centre Wellington is actively monitoring the infestation thresholds based on the principles of Integrative Pest Management to determine if and when aggressive management strategies are appropriate. LDD is firmly established in North America and was first detected in Ontario in 1969. For more in-depth information about LDD visit Ontario.ca.

LDD infestation severity follows a 7-10 year cycle. This makes predicting infestation rates and overall impact to residents and the Township of Centre Wellington challenging.

Lifecycle of the LDD Moth

How to spot an infestation

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.

Symptoms and Damage

LDD larvae chew holes in leaves or devour entire leaves so that only leaf veins remain. If severe outbreaks occur, trees and shrubs are completely defoliated over large areas. In most cases trees are able to produce a new crop of leaves over the summer and make a full recover, however repeated severe defoliation will lead to mortality. In addition, gypsy moth infestation can be a contributing factor in tree mortality for trees that are weakened by secondary pests, drought, and poor growing conditions.


When mature, LDD caterpillars are approximately 50 mm long, hairy and dark-coloured. Five pairs of blue dots and six pairs of red dots line their fuzzy backs. Male LDD moths are mainly brown and females are mainly white. Female moths are also flightless and often lay eggs inside bark cracks and crevices or on the underside of tree branches, as well as sheltered spots on rocks, logs or lawn furniture. Spongy egg masses can be observed on trunks and branches of infected trees from August-May

Public Trees

Public trees are trees owned by the Township of Centre Wellington on public land. This includes all park/greenspace trees, street trees (boulevard trees and those within the road allowance), and boundary trees.

When caterpillars are active (late May to late July), controlling LDD on public trees can be done by squishing or crushing caterpillars, or by removing caterpillars and placing them in soapy water to drown them. Care must be taken when handling the caterpillars as some individuals are allergic to the coarse hairs that cover and protect their bodies. It is recommended that gloves are worn when handling the caterpillar. Approximately 9-15 days after the caterpillars enter the pupa stage, moths appear. Removing egg mases by placing them in soapy water for two (2) days is also an effective method of control.

Using burlap as a control measure on public trees is not permitted at this time by the Township of Centre Wellington. Spraying public trees for pests such as gypsy moth can only legally be done a done by a license pesticide applicator under the direction of Township staff following all requirements of Ontario Pesticide Act.

Private Trees

Private trees are trees located on private property not owned by the Township of Centre Wellington. This includes trees within your backyard, behind the property line in your yard, and privately owned woodlots.

Treating LDD on private trees can be done by squishing or crushing caterpillars, removing caterpillars by placing them in soapy water to drown them, spraying with pesticide following all label requirements and safety precautions. BtK is a common household pesticide used to control caterpillars and can be purchased at most local garden centers and hardware stores. Burlap bands attached to the trunk of trees and checked twice a day to remove caterpillars seeking shelter from the sun is also an option.

How can I tell if my tree is Public or Private?

  • A tree located between the road and sidewalk on the boulevard will be a public tree.
  • A tree located between the road and water shutoff valve will likely be a public tree.
  • A tree located between the road and bell boxes, hydro poles, and Wightman boxes will likely be a public tree.
  • A tree located within the typical 66’ road allowance will likely be a public tree.
  • If you are unsure whether your tree is public or private and want to know appropriate treatment options please contact parks@centrewellington.ca and staff will provide information and assistance determining ownership.

Preventative Maintenance

If caterpillar infestation was observed on trees the following spring/summer egg masses may be noticeable attached to the bark of those same trees from August-May. Egg masses are a white/beige colour with a hairy exterior. Egg masses can contain several hundred eggs so removing them is the most effective method for preventing an infestation from occurring the following year. To remove and dispose of egg masses, scrape the masses into a bucket of warm soapy water with a putty knife, trowel, paint stick, or any other object with a smooth, flat surface. This provides the easiest way to remove all eggs within the egg masses quickly and effectively. Leave the eggs in the bucket of soapy water for 48 hours to break down the outer protective layer of the eggs to ensure they don’t hatch next year. Scraping the egg masses onto the ground or attempting to crush them is not an effective strategy and may result in some of the eggs hatching the following season.

Egg Mass Removal Video: How to Remove Gypsy Moth Egg Masses - YouTube

What can you do?

Email parks@centrewellington.ca with your LDD sightings including your address, information on affected trees, and estimated number of caterpillars/moths/egg masses.

Here’s what you can do to protect your trees and help control the spread:

  • In the summer and fall, physically remove gypsy moth egg masses. Use a putty knife or trowel to scrap eggs into a container and destroy the eggs by leaving them in soapy water for several days.
  • In the spring, apply sticky bands or burlap around trees to trap emerging LDD caterpillars. Commercial sticky bands can be found at most home and garden stores.
  • Use gloves to hand-pick caterpillars and crush.
  • Contact a professional tree care service provider to discuss spraying.

Check out our FAQ document on the right for more information.

View the LDD Caterpillar Save Your Trees with Proper Identification and Control video.