Note: Aerial spraying operations have been completed. No further spraying operations are scheduled to occur. City staff will continue to monitor the treated areas throughout the growing season to evaluate the effectiveness of the aerial spray.

Aerial Spray Program

This coming spring, the City of Toronto will be conducting an Integrated Pest Management program to control rising populations of European gypsy moth (EGM) in various locations across the City.  This program will include a variety of ground-based control methods as well as an aerial spray component.
Two helicopters will be applying the product Foray 48B Biological Insecticide Aqueous Suspension, containing the active ingredient Bacillus thuringiensis, ssp. kurstaki strain ABTS-351 (Btk), (PCP# 24977) under the Pest Control Products Act (Canada). 

The City has prepared this informational presentation for residents to help them understand the details surrounding the upcoming Aerial Spray Program.

During an aerial spray treatment program, highly trained spray specialists will use helicopters to spray an organic pesticide, Bacillus thuringiensis subspecies kurstaki (Btk), over designated areas to reduce populations of gypsy moth. The spray will produce fine droplets that are small enough to stick to the leaves of trees.

Btk produces a protein that is toxic only to the larvae (caterpillars) of specific insect species. When ingested by susceptible insects, the toxic protein molecules breakdown the walls of the insect’s stomach causing them to stop feeding. The insect usually dies within two to five days.

Although the aerial spray won’t eradicate all of the gypsy moth in the treated areas, the objective of the treatment is to lower populations to a more manageable level thereby reducing the severity of the damage to the tree canopy in these areas.

Areas affected by the aerial spray program

The spray will treat mainly areas of Etobicoke but will also include areas around Casa Loma, Leaside and Moore Park, as well as Rosedale.  It is expected that there would be severe leaf loss from caterpillar feeding. The total area to be treated is roughly 1,350 hectares (3,335 acres) of private and public land in Wards 1, 2, 3, 4, 11, 12 and 15.

Spray dates and times

The timing of the spray is set to occur between May 16 and June 15, 2019. Spraying operations are ecologically sensitive (e.g., dependent on leaf size, caterpillar development and weather) which prevents staff from selecting exact dates until 48 hours prior to a spray from occurring.  Once a spray date is confirmed, the date and time along with other additional information will be communicated to residents at a minimum 48 hours prior to the spray from occurring.

Two applications of the insecticide are scheduled to be applied with a 5-7 day interval between each application.  Given the substantial size of the areas scheduled for treatment and the narrow 2.5-hour window (5:00 A.M. -7:30 A.M.) each day that the helicopters are allowed to operate, each application will be broken up over 2 days for a total of 4 days that the helicopters will be operating.

How can I receive information and updates about the aerial spray program?

This website will be your best source of information regarding the aerial spray program.  Any updates, spray dates or cancellations will be posted here once information becomes available.

If you would like to be notified immediately by email of any updates regarding the aerial spray program, it is recommended that you subscribe to Gypsy Moth Aerial Spray E-Updates.

Sign up for Gypsy Moth Aerial Spray E-Updates here.

Updates on the program will be posted on the City's as well as the Parks, Forestry and Recreation Twitter and Facebook channels.

In addition to these options, Urban Forestry staff have scheduled a series of Information Open Houses for members of the public to attend.  Details regarding the aerial spray as well as information in what you can do as a homeowner to help manage EGM around your property will be discussed.

Questions, Concerns?  

The City has prepared an FAQ document that will hopefully answer most of your questions.

If you have additional questions or concerns regarding the 2019 Aerial Spray program, please call 311.  Service representatives are available to take your call and help to answer any questions you may have regarding the program or put you in contact with an Urban Forestry representative who can assist you further.

Residents with specific medical or health concerns regarding the spray can call Toronto Public Health.

Infested Trees on Private Property  

During the 2018 surveys, Urban Forestry staff identified some privately-owned trees that are potentially at risk of damage from the EGM. Depending on the treatment program being executed, the City will generally provide treatment for City-owned trees, however, homeowners are responsible for treating privately-owned trees.  If a private tree is identified as having a potentially damaging level of gypsy moth egg masses present, homeowners have been notified about the privately owned tree(s) that require attention by a drop-off notice. The City is available to work with homeowners by providing advice for the implementation of treatment for trees on their property.  It is important to remember that some understory trees, shrubs, and vegetation, in general, do not receive the pesticide on their leaves during an aerial spray. Caterpillars feeding on untreated vegetation are likely to survive and continue their life cycle for the next season.  Homeowners are strongly encouraged to survey their properties which would include landscaping structures (ie., pergolas, play structures, underside of decks) and exterior of their house (e.g. soffits, window ledges and window wells) and to remove egg masses as they are noticed in order to have more effective control for the following growing season.  The Gypsy Moth Control Methods: Guide for homeowners contains information on how to effectively remove egg masses and dispose of them as well as other control options that are available to homeowners.

To aid in our monitoring program, Urban Forestry staff encourage residents to report any signs of European gypsy moth to  311 so it can be properly documented and investigated.

Related information: