Lymantria dispar dispar (LDD) Moth - European Gypsy Moth*

*The Latin name for the European Gypsy Moth is Lymantria dispar dispar (LDD). Note we are transitioning to the term LDD moth following the announcement officially dropping the name “gypsy moth”.

LDD moth is an invasive and destructive pest that poses a risk to tree health by severely defoliating deciduous and coniferous trees. The larva hatch in April to June. The caterpillar stage is the most damaging to our tree populations as they eat the leaves. Large populations of LDD moths have a larger impact on our environment and our forests. Continuous defoliation causes the tree to lose its strength and can eventually lead to the tree dying.

The LDD moth overwinters in the egg stage often on the bark of trees. In the spring, eggs hatch and the caterpillars feed on the leaves of the tree. Feeding occurs during the day, but as the caterpillars mature feeding happens mainly at night. By July, the caterpillars are done feeding and progress into the adult moth stage. In late July, spongy egg masses can be observed on the trunks and branches of infected trees. Egg masses can be easily controlled by removing and burning or soaking with soap and water mixture.

LDD moth infestation ranges are expanding in Lanark County. Do your part by learning how to identify the LDD moth during various life stages. For more information about the impacts, life cycle, and how to control LDD moths on your property see the LDD moth fact sheet developed in partnership with the Invasive Species CentreEastern Ontario Model Forest, and Lanark County.

Additional Resources

What to expect and what to do with the LDD moth for the summer of 2021

LDD Moth Invasive Species Centre

LDD Moth Government of Ontario


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