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.

Scrape egg masses off surfaces into soapy water to destroy them:
1. Wear gloves and safety glasses for protection.
2. Place a container below the egg mass.
3. Use a plastic scraper tool or butter knife to remove the egg mass.
4. Empty the contents into a bucket of soapy water.
5. Leave the eggs sitting in the bucket for two days to destroy the eggs.
Helpful videos to reference:
Spongy (LDD) Moth Egg Mass Removal
Source: The City of Toronto
Finding and Removing Spongy (LDD) Moth Egg Masses
Source: The City of Toronto
How to Remove Spongy (LDD) Moth Egg Masses
Source: The City of London
How to protect your trees from LDD moths
When the caterpillars are in their first instar (tiny stage) they will dispense in the wind and fall to the ground. Instinctively, they find a tree, crawl up to the canopy and begin feeding. Sticky tape can be applied around the tree trunk to prevent caterpillars from reaching the top of the tree.
1. Wrap two layers of duct tape around the tree then twist is so that the sticky side of the tape is on the outside. Wrap it several times. It should be at a height of 5 feet from the ground.
2. Complete step 1 but do it a foot below the first tape wrapping.
3. If the tape is no longer sticking or full off caterpillars remove tape and reapply.
4. Remove tape in August to prevent damage on the tree trunk.
Helpful video to reference: Tree wrapping to mitigate spongy (LDD) moths
Source: The City of Grand Rapids
If you taped your tree in the spring, remove the tape to prevent damage to the tree.
Place Burlap Bands Around Tree Trunk
When the caterpillars are in the large caterpillar stage they will move down the tree during the day to seek shelter then return up the tree to feed at night. Placing burlap bands around the tree trunk provides a resting place for caterpillars which can be removed and killed. You will need burlap (length depends on the size of the tree but about 2' wide for the overhang), twine and rubber gloves.
1. Wrap a piece of burlap cloth around the tree trunk.
2. Tie rope around the center of the burlap.
3. Drape the burlap cloth over the rope. This will create an overhang where the caterpillars can crawl underneath to seek shelter during the day.
4. Check the trap by lifting the overhanging burlap cloth every afternoon and collect any hiding caterpillars.
5. Put them into a bucket of soapy water for a few days to destroy them.
Helpful video to reference: Spongy (LDD) Moth Burlap trap for caterpillars Source: The City of Toronto
Collect Pupae (Cocoons)
The spongy (LDD) moth caterpillar morphs into the pupal (cocoon) stage in July. This stage generally lasts 10 to 13 days. To help control next year's population, collect the pupae, put them a pail of soapy water, and leave them in the pail for a few days. Then dispose of the pupae in a sealed garbage bag.
Leave Dead Caterpillars in Place on Tree
If you notice dead caterpillars on your tree, leave them. Dead caterpillars indicate decline. If you leave them, it will help spread the virus or fungus that kills the caterpillars.

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 ServiceBarrie@barrie.ca. 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.

City staff continue monitoring spongy (LDD) moth populations along with the County and Province.
Spongy (LDD) moth outbreaks usually occur every 7–10 years and may last for a period of 1–3 years. 2022 was expected to be the last year of the outbreak. Spongy moth populations naturally collapse from the NPV virus and fungal Entomophaga maimaiga. We cannot eradicate this moth as it is well established throughout North America.
2023 is expected to have minimal spongy moth populations, with only light pockets of defoliation in a few locations. All affected areas and adjacent woodlands will be surveyed and monitored in 2023 to keep track of local populations. Learn more about spongy moth.
Overview of the Spongy Moth Population Outbreak (2020–2022)
2021 was a significant year for spongy moth infestation in Ontario. City staff acted in high infestation areas through an Integrated Pest Management Approach.
In 2022, surveys of egg masses in areas of high spongy moth populations estimated a 90% population collapse in most areas of Barrie. However, there were a few areas of significant caterpillar hatch (including the north portion of Sunnidale Park, Barwick Park, Hogans Woods, Vine Crescent Ravine, as well as areas in southeast Barrie). City staff monitored these areas and implemented the following Council approved program in 2022:
- April to early May – egg mass scraping of City trees in significant areas, as well as sharing educational material the City's website and social media channels
- Early May – distribute educational information for landowners, hold public education sessions to provide instruction and advice on protecting private trees
- Late May to mid June – sticky-banding City park trees, injecting TreeAzin to protect high value city trees where multiple years of defoliation has occurred, as well as further public education and information sessions
- Mid June to end of July – burlapping park and street trees in high-population areas, continue with public education efforts
- August – egg mass scraping and public education to prepare for 2023
In 2006, City staff instituted a moratorium on planting Ash species on public lands in Barrie and recommended that land developers and consultants omit ash from planting on private property. As of April 1 2014, the County of Simcoe (including Barrie) has been included in the zone under regulation for EAB. Signs and symptoms of EAB-infested ash trees:
- premature yellowing of leaves
- dead branches
- thinning crown
- branches sprouting from the base of the tree
- bark cracks
- a “zig-zag” path under dead portions of bark, and
- D-shaped holes from where new adults exit the tree.
If a City tree exhibits these signs please report to Service Barrie at 705-726-4242 or ServiceBarrie@barrie.ca. If you're concerned that your private tree is infested, staff suggest calling a certified arborist to have it inspected. There are several local tree companies with certified, licensed and insured arborists who can assess your trees and provide recommendations on the best course of action.
Phase 1: 2012 until EAB is discovered in Barrie
a) Identify specimen ash trees for treatment
b) Begin systematic removal and replacement of young ash trees on boulevards
c) Proactive planting in areas of high ash component
d) Public education on EAB
Phase 2: Post Discovery of EAB in Barrie
e) Begin bi-annual treatment of specimen ash
f) Systematic removals to include mature ash where integration with other programs create efficiencies (e.g. block pruning program)
g) Removal of all ash trees on a street or within a park where EAB has been discovered.

On March 26, 2012, after review of Staff Report re Pest Preparedness, Council adopted the EAB Program, a 2-phase project expected to last 15 years. In August 2014, EAB was confirmed within several locations in Barrie. As a result, forestry staff commenced Phase 2 of the EAB Program.
Please refer to tree removals due to Emerald Ash Borer to view areas of the city where street boulevard Ash trees must be removed.
ALHB is native to China and is considered a major pest of hardwood trees in many parts of the country. Based on the Chinese experience with this insect and the infestations in the United States and Vaughan, this beetle would survive and reproduce in the hardwood forests of southern Canada.
A variety of hardwood trees serve as hosts to ALHB. In Asia, the primary hosts are maple (Acer), poplar (Populus) and willow (Salix). Other hosts include; horse chestnut (Aesculus), birch (Betula), elm (Ulmus), sweet-gum (Liquidambar), ash (Fraxinus), mountain ash (Sorbus), mulberry (Morus), plum (Prunus), pear (Pyrus), black locust (Robinia), silk tree (Albizia), hackberry (Celtis), and sycamore (Platanus). All of these genera represent over 1,000 vulnerable species; the first five genera have been found to support reproducing populations in New York and Vaughan.
The ALHB infestation is considered “under control” within the Vaughan/Toronto Regulated Area, and the CFIA are monitoring the area for any further signs of its presence. However, ALHB was found in Mississauga in September 2013, prompting the CFIA to begin the process of starting an eradication program for that population. City staff continue to monitor the CFIA information provided on this pest.

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 ServiceBarrie@barrie.ca. If it's found on your own property please report on EDDMaps Ontario.