Gypsy moth

The European Gypsy Moth is a major forest pest concern because the caterpillar, or larva stage of the insect, eats the leaves of trees, defoliating them, which makes them more susceptible to disease and damage from other insects, like tent caterpillars. Continued defoliation of trees can lead to their decline and eventual death.

A single gypsy moth caterpillar can eat an average of one square metre of leaves.

The City is taking an Integrated Pest Management (IPM) approach. This means we are using different management techniques to address the pest population starting with the least harmful to the environment. At this time, spraying is not part of the IPM.

You can take action to remove gypsy moths and reduce the risk of infestation as caterpillars grow larger, and later in the summer, turn into moths and begin to breed.

What to look for: The caterpillars of the gypsy moth are dark and hairy. They have five blue dot pairs and six red dot pairs on their back. They go through 4-5 "molting" events where they shed their skin and each time, they get bigger.

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

Trapping tips

May to July – hand pick caterpillars

Gently shake plants and small trees so caterpillars fall from leaves. Thoroughly inspect the remaining foliage, branches, and trunk for caterpillars and using gloves, pick them off your tree. Fallen and collected caterpillars should be placed and left to soak in soapy water to destroy them.

July to August – burlap banding

Once the caterpillars grow to about an inch (2.5 cm) in length by mid-June, they will move down the trunk. Reduce the number of larvae on the trees in your yard by trapping them.

  1. Wrap and secure a piece of burlap cloth around the stem/trunk of your tree
  2. Tie twine or rope around the center or slightly below the center of the burlap
  3. Drape the burlap cloth over the twine or rope so there is an overhang where the caterpillars can crawl underneath to seek shelter during the day
  4. Check the trap by lifting the overhanging burlap cloth every afternoon and collect any hiding caterpillars
  5. Put them into a bucket of soapy water for a few days to destroy them
July to August – trap female moths

To trap female moths, wrap burlap lower on the trunk of the tree to trap the female moth (which are unable to fly) before it crawls up the tree and lays eggs. This is the same method used for the larger caterpillar stage. Once captured, drown the moths in soapy water.

July to August – trap male moths

Hang pheromone traps in trees to attract male moths, which prevents them from mating with female moths and producing eggs. Once captured, drown the moths in soapy water.

November to late April (egg stage) – destroy egg masses

Survey your property for egg masses and scrape them off surfaces into soapy water to destroy them.

  1. Place a container below the egg mass
  2. Use a scraper tool to remove the egg mass from the surface. Ensure that all eggs are scraped. Try not to leave any residual eggs in bark ridges or crevices
  3. Empty the contents of your catchment container or bag into a bucket of soapy water
  4. Leave the eggs sitting in the bucket for a day or two, then dispose of the contents

 

Last modified:Wednesday, October 07, 2020