© 2021 — Grey Sauble Conservation Authority

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

The Lymantria dispar dispar (LDD) moth is native to Europe. It was introduced to Massachusetts in the 1860’s, and quickly escaped into nature. The moth is a non-native invasive insect that was first found in Ontario in 1969. The first serious outbreak in Ontario was documented in 1981 in the Kemptville area.

This insect is a defoliator, meaning it eats leaves, of many tree species in Ontario. In southern Ontario, host species include sugar maple (Acer saccharum), American beech (Fagus grandifolia), eastern white pine (Pinus strobus), balsam fir (Abies balsamea), Colorado blue spruce (Picea pungens), but their preferred host are oak (Quercus sp.) species.

Outbreaks normally last 2-3 years and population collapse is caused by natural factors such as cool wet weather, cold winter temperatures (below -20 to -25 Celcius), starvation due to lack of food, biocontrols such as nuclear polyhedrosis virus (NPV) and Entomophaga maimaiga fungus, egg parasitoids, ground beetles, and larval parasitoids.

Photo: www.ontario.ca

What is GSCA Doing about LDD?

GSCA Staff are monitoring damages from the larvae stage (caterpillar) as well as monitoring for the presence of egg masses, moths, and pupae.

Ministry of Northern Development, Mines, Natural Resources and Forestry (MNDMDRF) staff complete annual aerial forest health surveys for numerous invasive species, including the LDD moths. GSCA staff communicate with MNRF staff about their findings.

Visit the MNDMNRF's Lymantria dispar dispar website for more information and to view a map of areas defoliated by LDD moth across Ontario.

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Property Closures:

    • – Eugenia Falls is now closed for the fall/winter season 
    • – Indian Falls is closed due to flooding on the trails. 

Please read Visiting Conservation Areas for important info.

Please note that we are currently operating at a temporarily reduced capacity while also experiencing a high number of applications and inquiries to our Environmental Planning Department at this time. Please use our contact form only for inquiries related to planning and development permits. Inquiries must include all requested information for a response by a planning staff member.


The GSCA office is open again to the public. The lobby will be open between 9am-12pm and 1pm-4pm (Monday-Friday) for individuals to drop off items, pick up any necessary materials, and to pay for services. COVID-19 self-screening will be required prior to entering the building and masks are mandatory. Meetings with staff will be by appointment only starting on October 18, 2021.

Some GSCA staff will be working remotely and may not have access to office phones.

Please utilize email or website contact forms (for planning and development permit related inquiries) as the most reliable way to reach our staff at this time.

Visit this link for more information about visiting properties during COVID-19.  Please visit this link for ongoing updates related to COVID-19.

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