Forestry Pests & Diseases

Urban forestry preventative maintenance programs include pest preparedness measures to ensure that the City of Barrie’s trees are safe and healthy.

There are several diseases and insects that affect trees. Some trees are more susceptible to certain diseases while other trees might be the preferred host for specific insects. Many of these insect populations are kept under control through natural predators and pathogens.

If populations arise to an infestation the City takes on an Integrated Management Approach. Different management techniques are used to address pest populations starting with the least harmful to the environment.

Invasive Insects in Barrie

Invasive insect species to be on the lookout for in Barrie:

  • Asian Longhorned Beetle: Attacks mainly maple trees, but also poplar, birch, willow and elm.
  • Emerald Ash Borer (EAB): Attacks and kills all species of white, green and red ash trees (Fraxinus). Poses a major economic and environmental threat to urban and forested areas.
  • Spongy (LDD Moth): Feed on tree leaves, destroying tree growth and taking away trees' ability to produce new leaves. Prefer oak, birch, aspen, sugar maple, American beech, eastern white pine and Colorado blue spruce trees.

    Note on the naming convention of the moth: On March 2, 2022, the Entomological Society of America adopted "spongy moth" as the common name for the LDD moth. The common name of LDD moth went under under review internationally and within Canada, including by the Canadian Food Inspection Agency. The City of Barrie therefore referred to the moth as "spongy (LDD) moth" for the 2022 season.

Protect your Trees from Spongy (LDD) Moth Infestation

2021 was a significant year for spongy (LDD) moth infestation in Ontario and staff applied an integrated management approach on City property in specific areas, which will continue into 2022. Steps to protect trees on your property are outlined below and should be continued in 2022.

Residents who would like to help beyond their property can submit a Departmental Contact Form to Parks Maintenance & Operations for information.

Once in the moth stage, there are few control options. The moth stage is short-lived and it's best to focus on the other stages when applying control methods.

Boulevard Tree Health Concerns

If you are concerned about the health of your boulevard tree due to spongy (LDD) moth infestation, please provide your address to Service Barrie at 705-726-4242 or An inspection workorder will be created to review the health of your tree following this season’s LDD moth outbreak (fall 2022​). Note: If your tree is in overall good health, defoliation will only stress your tree, not kill it.

Pest Preparedness

Urban forestry staff are responsible for pest preparedness programs and monitoring on City property. Urban forestry preventative maintenance programs include pest preparedness measures to ensure that the City’s trees are safe and healthy.

Two serious threats to the health of our urban forests have been monitored by staff since 2004: the Emerald Ash Borer (Agrilus planipennis) and the Asian Longhorned Beetle (Anoplophora glabripennis). No natural predators or control agents are known to control the populations of these two insects.

Reporting Pests & Diseases

It is critical to properly identify new introductions and be on the lookout for invasive species before they get established. The spread of pests and diseases cause harm to the ecosystem, economy, society, and potentially human health. If you think that you have spotted an invasive species on City property, please send photos and report location details to Service Barrie at If it's found on your own property please report on EDDMaps Ontario.