Modern Mississauga and the City of Mississauga have come together to present an ongoing series called “Ask the City.”
We’ll share relevant information here and answer your questions about our city.

Today’s question is about Gypsy Moths

What are gypsy moths and why is there a management program?

Gypsy moths are an insect that has been introduced to North America from Europe. Gypsy moth caterpillars cause tree destruction by feeding on the leaves of oak and other deciduous trees. An ongoing gypsy moth infestation can cause trees to die or become so weakened that they are vulnerable to secondary infestations.

2021 Gypsy Moth Management Program

The City is launching its annual Integrated Pest Management program to help reduce the number of gypsy moth caterpillars in Mississauga. The City will focus its management efforts in areas of the city that have higher populations of gypsy moth egg masses. Three strategies will be implemented:

1. Egg Mass Scrapings: scraping gypsy moth eggs off infested trees and soak egg masses in soapy water for at least 48 hours to kill eggs.

2. Tree Injections: injecting trees with TreeAzin® a botanical insecticide. Tree injections are anticipated to be conducted in four City parks: Applewood Hills Park, Paul Coffey Park, Huron Park and Sugar Maple Woods.

3. Ground Sprays: licensed operators will use a product containing Bacillus thuringiensis subspecies kurstaki (Btk). Heavily infected trees will be sprayed from the ground using a controlled mechanism such as a pressurized hand-held hydraulic sprayer. Ground spraying is anticipated to be conducted in two city parks: Cedarbrook Park and Jaycee Park.

How to spot an infestation

Gypsy moths like to eat the leaves on trees while they are in their caterpillar stage. They will strip the leaves until early summer, when they enter their moth stage. Look for trees with many caterpillars and not a lot of leaf coverage. They prefer oak trees, but will eat the leaves of any hardwood tree such as oak, maple, ash, birch or elm.

What you can do

The City is launching an Interactive Treatment Map and a Reporting Form this year. The Interactive Treatment Map displays publicly-owned trees along specific streets and in certain parks proposed for treatment. The Reporting Form will allow residents to report gypsy moth observations by inputting details including quantities and life stage observed and sharing photos.

You can also use some of these pest control techniques to help protect trees on your property:

• Remove caterpillars from tree trunks and soak in soapy water (most effective May-July)

• Install burlap wrap to catch caterpillars before you remove and kill them (most effective May-September)

• Install pheromone traps to confuse male months (most effective June-August)

• Search for egg masses and remove them from trees by scraping them off and soaking them in soapy water (most effective August-May)

For more information about gypsy moths, email tree.pests@mississauga.ca or call 311 (905-615-4311 from outside City limits).

If you’ve got a question about the City, we want to hear from you! 
Please send your questions to info@modernmississauga.com with “Ask the City” in the subject line.