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Date: 2020-10-02

Subject: AIA: Gypsy Moth/Caterpillar Infestation Programs

Bartlett Report Gypsy Moth 2018.pdf OCFDC Foray Brochure.pdf GYPSY MOTH OCFDC FAQ.pdf

Dear AIA Members,

At this year’s AGM several members expressed interest in potential solutions to the gypsy moth outbreak anticipated for next year.  To that end, we contacted Bartlett Tree Service and Zimmer Air for guidance. Below is what we have learned. 

Feedback from Bartlett Tree Service

Bartlett’s position is that mass overhead spraying is ineffective, in that it doesn’t kill all the moths, and inefficient, as it washes away with the next rain and it kills other unintended native insects.

Bartlett instead recommends injecting mature oaks and other vulnerable species with an insecticide that kills the moths at the caterpillar stage when they consume the leaves.  They also spray the egg masses on any tree with a horticultural (dormant) oil. An information sheet is attached.

Bartlett also indicated:

  1. The injections will take place from the middle of May 2022 to the second week of June 2022.  It may vary by a week or so based on weather. They will determine if dormant oil is needed at a site visit between now and next spring.
  2. The cost will be determined after a site visit and is based on diameter of the trees and number of trees being treated.
  3. They will apply a bulk discount after the properties are signed up. The discount will increase as the number of properties signed up increases. The discount will range from 10%-20% with a maximum discount of 20%. They will apply it after the first 10 properties are signed up and increase as more properties are added. The cutoff date will be April 15, 2022 and assumes that properties would be in the ‘same neighbourhood’.
  4. For inspection of your property and a proposal/cost estimate contact Erin at 705-646-8733, who will schedule Isaac Boyes for a site visit (705-801-5651).

The Bartlett price for mature trees can be $200-300, including a required root flare injection treatment and a defoliator spray treatment.  On my property for example, it was recommended that approximately 10-12 trees be treated.  This does not include tree fertilization which could be required for trees which were severely impacted by this year’s infestation

Feedback from Zimmer Air

Zimmer uses helicopters to spray.  They use Foray natural biological Insecticide which has been developed to protect trees from harmful defoliation against caterpillar pests including gypsy moths.  It is harmless to humans, pets, birds, and fish, etc.  See the attached product sheet or visit for further information.

Zimmer has engaged a separate company, the Ontario Centre for Defoliator Control to handle the administration of the 2022 program. This company will be the go-to for all gypsy moth-related inquiries for the 2022 season. The application to engage their services can be found on their website:  Phone number is 1-888-276-9372.

Once the application has been submitted, one of the OCFDC representatives will begin mapping your property (via Google Earth) and follow up with all the necessary information about the coming year’s program. Please be patient as the list of people interested in the program is extensive and may take months to process all of them.

Once the OCFDC representative has established the property lines, they will distribute the service agreement, waivers, and payment form with specific pricing for spraying your property. Wavers are required from neighbouring lots, and without them spraying will be directed to a 20m set-back from your lot line.

Cost of the program is $368 for the first acre and $99 for each additional acre (less than 1 acre is prorated). For large properties spraying can be isolated to the needed areas. Pricing is subject to change.

Contact Chris Bell, OCFDC at 226-627-4107, or the 1-888 number above, for further information or proceed directly to the application stage. 


Hopefully this information is helpful.  If you wish to explore either of these solutions it is likely best to begin the process of seeking proposals now versus leaving it to next spring as we anticipate supplier bookings to be strong.  As there are pros and cons to each method as well as other service providers, AIA members are encouraged to make their own arrangements.

A special thanks to AIA board members Hugh Kerr, Sandra Taube Godard and Malcolm Foulkes for their work on this program and this write up. 


Mike Lewis
President, Acton Island Association

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Acton Island Association,
P.O. Box # 271,
Bala, ON POC 1A0

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