European Gypsy Moth (EGM)

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EGM caterpillars

UPDATED MAY 17, 2021

CONFIRMED AERIAL SPRAY

DATE: MAY 20, 2021

TIME: 5:30 a.m. - 6:30 a.m.


This spray is being performed to help preserve existing trees from severe defoliation as a result of European gypsy moths (EGM). The aerial spray is planned to take place this Thursday, May 20, 2021. The entire City of London aerial spray program for all five (5) parks will take approximately 1hr starting between 5:30 a.m. and 6:30 a.m.

Work is significantly dependent on favorable weather conditions (lack of rain & wind) and may have to be rescheduled, which could be as early as the next day.


Any reschedule date will be posted here on this page.

The City of Toronto Aerial Spray Program

The bio-pesticide product is applied directly to tree foliage by a twin-engine helicopter equipped with an ultra-low-volume spray system. The aircraft flies about 15 to 30 metres above the tree canopies. Residents can expect high audible levels as the helicopter completes its once-over path.



UPDATED MAY 12, 2021

Current anticipated date range for the aerial spray is May 17-19

This page will be updated to reflect confirmed Aerial Spray date. Please check back frequently.

Please note that this is a range of dates were it is estimated that the aerial spray will take place. These date are significantly dependent on weather conditions. The entire spray program for London is estimated to take 1 hr.


UPDATED MAY 6, 2021

Current anticipated date range for the aerial spray is May12-18th.

This page will be updated to reflect confirmed Aerial Spray date. Please check back frequently.

Ideal conditions for applying Btk is when tree leaves have expanded to 40-50% and total egg hatch is at 90%. At this time, red oaks are at 5-10% expanded while white oaks are at 5-9%. Egg hatch is at 78-92%.



UPDATED MAY 3, 2021

This page will be updated to reflect confirmed Aerial Spray date. Please check back frequently.



UPDATED APRIL 14, 2021

This page will be updated to reflect confirmed Aerial Spray date. Please check back frequently.

Below is the 90% egg hatch map current as of 04/09/2021.


UPDATED APRIL 9, 2021

The City of London intends to control EUROPEAN GYPSY MOTH (Lymantria dispar) using the pesticide Foray 48B Biological Insecticide Aqueous Suspension active ingredient Bacillus thuringiensis v. kurstaki (Btk) Registration No. 24977 (Class 11) at the following five (5) municipal parks:

#LocationAddressEgg/HaDefoliation ForecastSpray Area (Ha)
1Fairmont Park117 Tweedsmuir Ave272,033Severe >90%4.02782
2Grand View Park385 Grandview St18,425Severe 80-90%2.06598
3Griffith Street Park561 Griffth Str47,633Severe 80-90%1.10249
4Crestwood Woods635 Boler Rd29,600Severe 80-90%2.61471
5Somerset Woods25 Fourwinds Rd15,100Severe 80-90%4.02782


Please see the documents list for the following information for each park:

1. Notification Area Map: Illustrating the parcels within 100 metres of each park. These parcels will be mailed notification letters regarding the aerial spray program 2 weeks in advance.

2. Adjacent Parcel List: Quick look up address list.

3. Aerial Block Spray: Illustration of the aerial spray path(s) that the helicopter will take over tree canopies in each park.

This page will be updated to reflect confirmed Aerial Spray date. Please check back frequently.


The City of London Aerial Spray Program 2021

The City of London has been monitoring the European gypsy moth (EGM) pest over the past two years with consultant BioForest/Lallemand Inc. as part of an Integrated Pest Management (IPM) Program. Last fall record breaking data was collected on defoliation (leaf loss) caused by EGM feeding. It was noted in several locations as severe which means that between 80-90% of the tree canopy was defoliated. Egg mass surveys have forecasted that these locations will be severely defoliated again in 2021. The City has manually removed egg masses from hundreds of street and park trees. However, due to the extent of the outbreak, and that it is moving from established locations into new, the City has contracted to aerial spray a biopesticide called Bacillus thuringiensis subspecies kurstaki, or commonly known as Btk. Btk is a naturally occurring soil bacteria that is present in our environment. It is not a chemical and is certified for organic use in Canada.

The aerial spray program will be using a biological pesticide called Foray 48B Biological Insecticide Aqueous Suspension, its active ingredient is Bacillus thuringiensis subspecies kurstaki. Registration No. 24977 under the Pest Control Products Act (Canada) for the management of European Gypsy Moth (EGM).

Pesticides in Canada are regulated by Health Canada under the Pest Management Regulatory Agency (PMRA). Pesticides are stringently regulated in Canada to ensure they pose minimal risk to human health and the environment. Under the authority of the Pest Control Products Act, Health Canada. Scientific studies are completed as part of the product’s registration process. Re-evaluating and monitoring the product continues after approvals.


Have you seen trees that have pink dots and flagging in City parks?

These are very important trees with a purpose and we ask that park users kindly do not remove the flagging or dots. These are tree stand plots which have been set up to monitor the emergence and activity of the EGM caterpillar and the leaf development of the trees. The City of London is working with BioForest/Lallemand Inc. to calculate the most effective date to perform the aerial spray. In addition to collecting real time biological and environmental information, new modeling software called BioSIM will also be used.

Allison Craig, Manager, Urban Forest Health Services with BioForest/Lallemand Inc.,
setting up EGM egg mass monitoring plots

Oak tree with white spray dots to monitor EGM egg masses




What you can do now

There are actions that we all can do to help stop the spread of this non native, invasive pest. The cold winter months are the time when you can be pro-active with reducing EGM, by removing egg masses on your trees. This video shows you exactly how to go about the removal.



Street tree egg mass removals

Scraping egg masses can be an effective tool in managing EGM, especially combined with other techniques. Each egg mass that is removed can have between 100 and 1,000 eggs. Last year, street tree egg mass scraping had a positive impact on reducing defoliation. This year, 37 streets with over 800 City-owned trees are forecasted to be severely defoliated in the following areas:

Click the links above to see the maps of the specific streets and trees.

City crews and contractors over six weeks manually removed approximately 23,000 egg masses from these trees. This is an estimated 2.3 million - 23 million caterpillar eggs.

Work was completed by scraping them from the ground and for larger trees using an aerial bucket truck. Arborist climbers were also used in challenging locations that were not accessible by a vehicle. Egg masses were removed from all sides of the tree, branches and limbs up to approximately 50’.

UPDATED MAY 17, 2021

CONFIRMED AERIAL SPRAY

DATE: MAY 20, 2021

TIME: 5:30 a.m. - 6:30 a.m.


This spray is being performed to help preserve existing trees from severe defoliation as a result of European gypsy moths (EGM). The aerial spray is planned to take place this Thursday, May 20, 2021. The entire City of London aerial spray program for all five (5) parks will take approximately 1hr starting between 5:30 a.m. and 6:30 a.m.

Work is significantly dependent on favorable weather conditions (lack of rain & wind) and may have to be rescheduled, which could be as early as the next day.


Any reschedule date will be posted here on this page.

The City of Toronto Aerial Spray Program

The bio-pesticide product is applied directly to tree foliage by a twin-engine helicopter equipped with an ultra-low-volume spray system. The aircraft flies about 15 to 30 metres above the tree canopies. Residents can expect high audible levels as the helicopter completes its once-over path.



UPDATED MAY 12, 2021

Current anticipated date range for the aerial spray is May 17-19

This page will be updated to reflect confirmed Aerial Spray date. Please check back frequently.

Please note that this is a range of dates were it is estimated that the aerial spray will take place. These date are significantly dependent on weather conditions. The entire spray program for London is estimated to take 1 hr.


UPDATED MAY 6, 2021

Current anticipated date range for the aerial spray is May12-18th.

This page will be updated to reflect confirmed Aerial Spray date. Please check back frequently.

Ideal conditions for applying Btk is when tree leaves have expanded to 40-50% and total egg hatch is at 90%. At this time, red oaks are at 5-10% expanded while white oaks are at 5-9%. Egg hatch is at 78-92%.



UPDATED MAY 3, 2021

This page will be updated to reflect confirmed Aerial Spray date. Please check back frequently.



UPDATED APRIL 14, 2021

This page will be updated to reflect confirmed Aerial Spray date. Please check back frequently.

Below is the 90% egg hatch map current as of 04/09/2021.


UPDATED APRIL 9, 2021

The City of London intends to control EUROPEAN GYPSY MOTH (Lymantria dispar) using the pesticide Foray 48B Biological Insecticide Aqueous Suspension active ingredient Bacillus thuringiensis v. kurstaki (Btk) Registration No. 24977 (Class 11) at the following five (5) municipal parks:

#LocationAddressEgg/HaDefoliation ForecastSpray Area (Ha)
1Fairmont Park117 Tweedsmuir Ave272,033Severe >90%4.02782
2Grand View Park385 Grandview St18,425Severe 80-90%2.06598
3Griffith Street Park561 Griffth Str47,633Severe 80-90%1.10249
4Crestwood Woods635 Boler Rd29,600Severe 80-90%2.61471
5Somerset Woods25 Fourwinds Rd15,100Severe 80-90%4.02782


Please see the documents list for the following information for each park:

1. Notification Area Map: Illustrating the parcels within 100 metres of each park. These parcels will be mailed notification letters regarding the aerial spray program 2 weeks in advance.

2. Adjacent Parcel List: Quick look up address list.

3. Aerial Block Spray: Illustration of the aerial spray path(s) that the helicopter will take over tree canopies in each park.

This page will be updated to reflect confirmed Aerial Spray date. Please check back frequently.


The City of London Aerial Spray Program 2021

The City of London has been monitoring the European gypsy moth (EGM) pest over the past two years with consultant BioForest/Lallemand Inc. as part of an Integrated Pest Management (IPM) Program. Last fall record breaking data was collected on defoliation (leaf loss) caused by EGM feeding. It was noted in several locations as severe which means that between 80-90% of the tree canopy was defoliated. Egg mass surveys have forecasted that these locations will be severely defoliated again in 2021. The City has manually removed egg masses from hundreds of street and park trees. However, due to the extent of the outbreak, and that it is moving from established locations into new, the City has contracted to aerial spray a biopesticide called Bacillus thuringiensis subspecies kurstaki, or commonly known as Btk. Btk is a naturally occurring soil bacteria that is present in our environment. It is not a chemical and is certified for organic use in Canada.

The aerial spray program will be using a biological pesticide called Foray 48B Biological Insecticide Aqueous Suspension, its active ingredient is Bacillus thuringiensis subspecies kurstaki. Registration No. 24977 under the Pest Control Products Act (Canada) for the management of European Gypsy Moth (EGM).

Pesticides in Canada are regulated by Health Canada under the Pest Management Regulatory Agency (PMRA). Pesticides are stringently regulated in Canada to ensure they pose minimal risk to human health and the environment. Under the authority of the Pest Control Products Act, Health Canada. Scientific studies are completed as part of the product’s registration process. Re-evaluating and monitoring the product continues after approvals.


Have you seen trees that have pink dots and flagging in City parks?

These are very important trees with a purpose and we ask that park users kindly do not remove the flagging or dots. These are tree stand plots which have been set up to monitor the emergence and activity of the EGM caterpillar and the leaf development of the trees. The City of London is working with BioForest/Lallemand Inc. to calculate the most effective date to perform the aerial spray. In addition to collecting real time biological and environmental information, new modeling software called BioSIM will also be used.

Allison Craig, Manager, Urban Forest Health Services with BioForest/Lallemand Inc.,
setting up EGM egg mass monitoring plots

Oak tree with white spray dots to monitor EGM egg masses




What you can do now

There are actions that we all can do to help stop the spread of this non native, invasive pest. The cold winter months are the time when you can be pro-active with reducing EGM, by removing egg masses on your trees. This video shows you exactly how to go about the removal.



Street tree egg mass removals

Scraping egg masses can be an effective tool in managing EGM, especially combined with other techniques. Each egg mass that is removed can have between 100 and 1,000 eggs. Last year, street tree egg mass scraping had a positive impact on reducing defoliation. This year, 37 streets with over 800 City-owned trees are forecasted to be severely defoliated in the following areas:

Click the links above to see the maps of the specific streets and trees.

City crews and contractors over six weeks manually removed approximately 23,000 egg masses from these trees. This is an estimated 2.3 million - 23 million caterpillar eggs.

Work was completed by scraping them from the ground and for larger trees using an aerial bucket truck. Arborist climbers were also used in challenging locations that were not accessible by a vehicle. Egg masses were removed from all sides of the tree, branches and limbs up to approximately 50’.

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Page last updated: 18 May 2021, 06:41