Harmful organisms and pests can cause damage to the environment and agriculture and involve risks that may affect public health and the proper conduct of human activities.

It is important, if you see any pests, to report noxious weeds or mosquitoes to the Environmental Health Department, together with the specific location where sighted (address, area on the property) and the approximate density of the pest. If possible, provide a photograph for identification purposes.

Harmful organisms

Poison ivy

In Quebec, three varieties of poison ivy may be found: Toxicondendron radicans, Toxicodendron radicans spp negundo, and Toxicodendron radicans spp. Radicans. All are commonly known as Eastern Poison Ivy. Each variety of poison ivy contains urushiol, a non-volatile chemical. This allergen is released when plant tissues are damaged.

These noxious plants start to appear in spring and early summer and die back in the fall. People who become sensitized may experience irritation or serious skin reactions. The public needs to recognize the plant and to refrain from touching its sap directly or indirectly.

For more information:

Space for Life (Montreal Botanical Garden)

Healthy Canadians (Government of Canada)

Ministère du Développement durable, de l’Environnement et de la Lutte contre les changements climatiques − Québec (French only)


In Quebec, three varieties of ragweed may be found: Common Ragweed (Ambrosia artemisiifolia), Giant Ragweed (Ambrosia trifida) and Perennial Ragweed (Ambrosia psilostachya). From late July to mid-September, the plants release large amounts of pollen in the air, which constitute almost one third of all pollens produced in southern Quebec.

This mass of pollen causes seasonal allergy rhinitis (hay fever). At least 17.5% of the provincial population suffers from the allergy.

Reducing the prevalence of ragweed is essential for public health. So, rip it out before the end of July!

For more information:

Ministère de la Santé et des Services sociaux – Québec

Space for Life (Montreal Botanical Garden)

The Quebec Lung Association

Giant hogweed

Giant Hogweed (Heracleum mantegazzianum) or Giant Cow Parsley can reach a height of 2 to 5 metres. It is considered a noxious weed and its sap causes phytophotodermatitis, resulting in blisters, burns and scars. It can also cause blindness.

Identification :

Stems are hollow

Stems and petioles have reddish-purple flecks, nearly solid purple at the base

Leaves are large and shiny with coarse, serrated edges

Flower stalks and leaf stems have stiff, bristly hairs

Giant Hogweed is often misidentified because of its similarity to Cow Parsnip. To learn more on how to identify Giant Hogweed and differentiate it from similar species, visit:

Ministère de la Santé et des Services sociaux – Québec

Ministère du Développement durable, de l’Environnement et de la Lutte contre les changements climatiques – Québec (French only)

Space for Life (Montreal Botanical Garden)


Mosquitoes thrive in stagnant water. Some good habits to adopt in order to prevent mosquito breeding are:

At the approach of summer, open your pool as soon as possible

Clean your gutters every spring

Empty outdoor items where water collects (flower pots, boilers, furniture, etc.)

Install screens on rainwater barrels.

Have you noticed a high presence of mosquitoes? Do you have questions about controlling biting insects? Call the Info-mosquito line at 1 (888) 567-8567.

For more information, view the following GDG Environment videos (French only):

West Nile virus

Since 2006, active surveillance for West Nile virus in dead birds has been terminated. Therefore, to provide preventive surveillance for avian influenza in Quebec, residents are urged to report any mortality of wild birds to Services Québec by contacting 1-877-644-4545.

For more information visit:

Portail santé mieux-être, gouvernement du Québec

Public Health Agency of Canada

Sand wasps

If you see insects swirling over sandy surfaces in Town parks or at the beach, take care. These are sand wasps. They measure two centimetres (3/4”), are coloured black and yellow or black and white and lay eggs in the sand. They are most active when temperatures are high.

As a preventive measure, you are advised to avoid sandy areas if you suffer from an allergy to wasps or are disturbed or frightened by their presence.

Ash Borer

Ash Borer, MRC Vaudreuil-Soulanges

Ash Borer, Town of Mount-Royal

Guide for detection surveys of EAB

Quebec Council of invasive exotic species

Bioforest Technologies inc.

Contact the Environmental Health Department

For all questions regarding Environmental Health, please contact (450) 458-5347.