Invasive Species

In response, Central Lake Ontario Conservation Authority has used herbicide and/or physical removal at Heber Down, Long Sault and Lynde Shores Conservation Areas, as well as at Hampton Pond. The Phragmites management at Heber Down Conservation Area has been ongoing since 2016, in partnership with Enbridge, Trans Northern Pipeline, and Hydro One. Extensive phragmites mapping has been completed at all eight Conservation Areas.

CLOCA Staff using chemical management to control Phragmites

Starting in 2023, CLOCA also partnered with the University of Toronto to release two species of moths as a biocontrol for Phragmites at Cranberry Marsh in Lynde Shores Conservation Area. The initial releases of both eggs and larvae of the moth were successful, with moth populations reproducing and overwintering successfully, and a significant reduction in Phragmites stem density and panicle (feathery flower) formation! Although these impacts were very localized, they inspire hope that, over time, the moths will reduce Phragmites on a larger population scale.

Four images showing the moth egg and larva releases in both wet (A and B) and dry (C and D) conditions at Cranberry Marsh. The eggs are held in a white container for release which helps protect them from predators, while the larvae are placed inside short sections of phragmites stems. Photos Credit: Ian Jones.

Boreholes in phragmites stems created by moth larva. Photo Credit: Michael McTavish

In response, Central Lake Ontario Conservation Authority has used extensive physical removal at Purple Woods Conservation Area starting in 2013 with CLOCA's high school education program, ‘To Beat It, We Eat It’. In this program, students spent half a day in the forest pulling garlic mustard and the other half in the kitchen making it into delicious pesto for gourmet pizza, pasta, and salad! This program ran from 2013 to 2019 and removed a whopping 1.4 tonnes of garlic mustard from the Purple Woods Conservation Area sugarbush!

Since 2019, CLOCA staff made efforts to continue to pull the garlic mustard every spring, but the end of ‘To Beat It, We Eat It’, coupled with disturbance to the sugarbush related to the 2022 windstorm, led to garlic mustard populations becoming unmanageable through pulling alone. A spot spray herbicide treatment was done in 2023, followed by an annual spring garlic mustard pull community outreach and volunteering event (typically in June).

Volunteers at the annual spring garlic mustard pull event with the bags of garlic mustard they pulled

In response, Central Lake Ontario Conservation Authority has used herbicide management of Dog Strangling Vine at Purple Woods, Crow's Pass, and Enniskillen Conservation Area, as well as Rogers Tract (part of CLOCA's Conservation Lands, not accessible to the public).

While CLOCA uses other management options where possible - like mechanical, manual, and biological controls - sometimes the most effective tool against invasive species is chemical/herbicide (as is the case with Dog Strangling Vine). When herbicide is used, care is always taken to minimize residual spray on native species.

Dog-strangling vine in action overcrowding our native provincial flower, the white trillium. Dog-strangling vine is outlined in red in the second image. Photo Credit: P. Martin

In response, Central Lake Ontario Conservation Authority has used herbicide management of European Buckthorn in the 15 acre meadow at Bowmanville Westside Marshes Conservation Area as well as in the 61.5 acre tall grass prairie site at Long Sault Conservation Area and Rogers Tract (part of CLOCA's Conservation Lands, not accessible to the public).

In response, Central Lake Ontario Conservation Authority has used herbicide management of Autumn Olive in the 15 acre meadow at Bowmanville Westside Marshes Conservation Area as well as in the 61.5 acre tall grass prairie site at Long Sault Conservation Area and Rogers Tract (part of CLOCA's Conservation Lands, not accessible to the public).

Though not currently found in CLOCA’s jurisdiction, Hemlock Woolly Adelgids are in Ontario and have been found as close as Grafton. Surveying for the HWA has been ongoing at Stephen's Gulch, Long Sault, and Enniskillen Conservation Areas since 2023. These three Conservation Area have an abundance of hemlocks and are CLOCA’s Conservation Areas that are closest to Grafton. Surveys are done using the ball-sampling method which involves using a slingshot to fling a Velcro-covered ball into the top of hemlock trees.

Velcro ball used for HWA surveys

HWA lays eggs in masses covered with white "wool" which will attach to the Velcro if present. For hemlocks with low branches, the underside of the needles can be checked for little white tufts, but ball sampling will give a more accurate result as HWA infestations typically start at the top of the tree.

Video showing a slingshot used to fling a Velcro-covered ball into a hemlock tree.

Additionally a 3D-printed trap that collects environmental DNA was installed at Stephen's Gulch Conservation Area in 2024 as part of a pilot project led by the Invasive Species Centre in partnership with Natural Resources Canada and the Canada Food Inspection Agency. The project was designed to maximize detection potential for the HWA, as early detection of invasive species is critical to successful management. The slides from these traps collect environmental DNA, including any traces of HWA DNA (if present).

So far, HWA has not been detected at CLOCA's Conservation Areas.

Trap installed at Stephen's Gulch Conservation Area.

What you can do to help stop the spread:

- Don’t place bird feeders near hemlock trees – HWA crawlers hitchhike on birds

- Don’t move firewood: burn where you buy! This will help stop the spread of many invasive insects.

- If planting hemlocks, buy local and inspect for “wool” before purchase

- Monitor and report HWA

- Learn more by checking out the Invasive Species Centre's Hemlock Woolly Adelgid Fact Sheet

Physical removal has been done at Pumphouse Marsh in south Oshawa since 2018. This species has only been found at three other locations in Ontario.

In response, Central Lake Ontario Conservation Authority has done distribution mapping, monitoring of tree health, hazard tree removal and restoration planning. Infected trees in CLOCA’s Conservation Areas have been marked with yellow dots as part of our ash tree inventory.

Ash tree with tunnels chewed by EAB larva visible under the bark.

Distribution mapping and reporting is done in partnership with Ganaraska Conservation and the Municipality of Clarington. If Giant Hogweed is found adjacent to any of CLOCA's trails, please report using the 'Report a Concern' form, by phone at 905 579-0411, or by email at mail@cloca.com.

Removal and follow-up monitoring is done along trails at CLOCA's Conservation Areas. If Wild Parsnip is found adjacent to any of CLOCA's trails, please report using the 'Report a Concern' form, by phone at 905 579-0411, or by email at mail@cloca.com.