Areas of Ontario, including Prince Edward County, are currently experiencing an infestation of Lymantria dispar (formerly known as “gypsy moth”) caterpillars in 2021.
These specific outbreaks/infestations happen in cycles, often occurring every seven to 10 years, with outbreaks lasting three to five years.
The Lymantria dispar is a non-native invasive caterpillar that feeds on the foliage of trees, such as oak trees, birch trees, aspen trees, White Pine, Balsam Fir, and Colorado Blue Spruce. This invasive pest defoliates trees and prevents new growth which stresses trees, making them more susceptible to damage from secondary pests, drought, and poor growing conditions.
Below are recommended actions you can take to protect your trees during each life stage of the Lymantria dispar moth:
August to Mid-April: Remove egg masses and discard. Click here to learn how
Mid-April to Mid-May: Apply biological pesticides to early stage caterpillars. Consult with your local arborist to determine what product is right for your situation.
Mid-May to June: Apply burlap bands and discard larvae. Once they are established and larger in size caterpillars will move down the tree trunk to seek shelter from heat and predators. Caterpillars will then rest on the burlap, which will allow property owners to easily remove and destroy the insects. Insects can be destroyed by submerging them in soapy water.
June to Mid-July: Remove pupae (stage between larva and adult) by hand and discard. Click here to view a photo of pupae
July to August: The lifespan of the adult moth is short lived; therefore, control methods should be focused on earlier stages.