Protecting our Trees: City Launches 2021 Gypsy Moth Management Program

The City of Mississauga is launching its annual Integrated Pest Management program to help reduce the number of gypsy moth caterpillars in Mississauga. This invasive insect causes tree destruction by feeding on the leaves of oak and other deciduous trees. After repeated defoliation, trees may die or become so weakened that they are vulnerable to secondary infestations.

The City will focus its efforts on areas in Mississauga 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.

“Gypsy moth caterpillars aren’t new to Mississauga. They have been around for more than a decade. They have caused a lot of damage to the City’s already vulnerable hardwood trees. Through our comprehensive Integrated Pest Management program, we have learned how to control their populations by using different pest management strategies,” said Jodi Robillos, Director, Parks, Forestry and Environment. “We have seen the destruction gypsy moths can cause to our urban forest and many of our diverse tree species. The preservation of our urban forest canopy is criticalbecause trees are an important component of a healthy ecosystem. The goal of the gypsy moth program is to control the population and preserve the health of Mississauga’s urban forest canopy. This is why our Integrated Pest Management program is important and why our continued efforts matter.”

New this year, the City is launching an Interactive Treatment Map and a Reporting Form. The Interactive Treatment Map will display the 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.

Over the next few weeks, City staff and contractors will be applying pest management strategies in certain areas around the city. Residents are reminded to maintain a physical distance of at least 2 metres (or 6 feet) from staff.

For more information about gypsy moths in Mississauga, visit

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