The City of Markham is using an Integrated Pest Management (IPM) strategy in conjunction with the Region of York and industry experts. IPM is a sustainable approach to managing pests that combines biological, cultural and physical factors to control in a way that targets a specific pest and minimizes impacts to others.

The following integrated pest management strategies are currently being used:

• Egg Mass Scraping and Removal

During the Fall of 2021 and the Winter of 2022, the City of Markham staff manually removed Spongy Moth egg masses from approximately 28,000 street & park trees. Staff visited every street within the City of Markham.

• Insecticide Injections

During the Spring of 2022, approximately 150 select high-value street and park Oak trees will be treated using an injectable biological insecticide called TreeAzin™.  TreeAzin™ is made from the seeds of the Neem tree and when injected, the insecticide will kill the caterpillar by preventing it from growing any larger. The caterpillar must ingest part of the trees leaves (which will contain the insecticide) in order for it to be successful.  Many municipalities, including Markham, have used TreeAzin™ in the past for the treatment and control of the Emerald Ash Borer (EAB) invasive species. Additional information on TreeAzin™ can be found at: https://bioforest.ca/en/canada/product-details/treeazin-systemic-insecticide/

• Burlap Banding Trap Kits

During the Spring of 2022, several events were held to provide distribution of pre-assembled burlap banding kits. Approximately 4,000 kits have been provided to City of Markham residents for use on their privately-owned trees.

• Monitoring and Data Collection

City of Markham staff continue to document neighbourhoods of ‘heavy’ to ‘severe’ defoliation impacts, to better plan for future strategies. Information collected and shared by neighbouring municipalities offer a variety of educational tools and resources.

• Plot Surveys and Further Studies

In July 2022, the Region of York will be conducting defoliation surveys on previously-surveyed plots to look at the actual defoliation levels (which the egg mass surveys in 2021 attempted to predict), and look for signs of the nucleopolyhedrosis virus (NPV). Actual defoliation versus predicted defoliation helps confirm the accuracy of the egg mass surveys and signs of NPV can be an indicator that the Spongy Moth population is declining.

In late fall/early Winter 2022, the Region of York will be re-surveying the plots for egg masses to help with 2023 Spongy Moth predictions and planning.