Invasive Plants & Pests

Invading species are one of the greatest threats to the biodiversity of Ontario's waters, wetlands and woodlands. Originating from other regions of the world, and in the absence of their natural predators or controls, invading species can have devastating effects on native species, habitats and ecosystems.

Visit Ontario's Invading Species Awareness Program's website

Visit the Canadian Food Inspection Agency's (CFIA) Plant Pest website

Invasive Insect Species

The Hamilton Conservation Authority monitors insect pests to determine their impact on local ecosystems. Here, we provide information on insect species that warrant concern in the greater Hamilton area.

Recent Pest Alerts for the Hamilton Area:

Two significant insect pests have been affecting cities close by Hamilton area: the Emerald Ash Borer and the Asian Long-Horned Beetle.

Emerald Ash Borer

emerald ash borerThe Emerald Ash Borer (EAB) is a highly destructive insect which kills ash trees. There are currently six regulated areas in Southwestern Ontario for EAB. Elgin, Lambton and Middlesex counties are regulated separately. Essex County and the Municipality of Chatham-Kent, which were separately regulated in 2004, were combined into one regulated area in June 2006. Norfolk County and the City of Toronto were regulated in 2008. Photo courtesy CFIA.

What do they look like?
Emerald ash borer adults are metallic green, 8.5 to 13.5 mm long, and slender. The head is flattened, with black compound eyes that cover most of the side of the head. Short antennae extend from the face, then curve back to just past the eyes. The upper side of the abdomen is copper to purplish, and is visible when the wings are open.

Why are they a threat?

  • The emerald ash borer is able to attack and kill healthy trees and all native ash species, of all sizes are at risk.
  • EAB larvae have been found in branches as small as 1.1 cm in diameter.
  • Ash trees are widespread in Canada and the United States, both in natural and urban settings, and green ash is one of the most commonly planted species in the urban forest.
  • Emerald ash borer is very difficult to detect early. When infested trees are found, it’s often 1 year or more after the attack occurred. In addition, there are several other factors affecting ash health in Ontario which may disguise its presence.
  • Estimates show the emerald ash borer has killed several hundred thousand ash trees in Essex County, Ontario, and 8 to 10 million ash trees in southeastern Michigan. Tree loss includes ornamental, rural and woodlot trees.
  • If not effectively controlled, the emerald ash borer is expected to spread across the entire range of ash, causing widespread tree mortality. (Information from the Ministry of Natural Resources).

CFIA Emerald Ash Borer Fact Sheet

Asian Long-Horned beetle
The Asian long-horned beetle (Anoplophora glabripennis) is a forest pest native to several Asian countries that attacks and kills a wide range of hardwood trees, including maple. Also known as the starry sky beetle, this destructive wood boring insect was found in an industrial park bordering Toronto and the City of Vaughan in 2003. It is a serious threat to the forests of Ontario.

The beetle is no stranger to North America. It was first found in New York in 1996, in Chicago in 1998, and in New Jersey in 2002 and again in 2004. A native of China, it was likely introduced into North America by way of wooden pallets, crates, or packaging materials used in shipping. Millions of dollars has been spent to eradicate the insect. Though these programs have been successful to date, any new sightings require immediate action.

What do they look like?
Asian Long-horned Beetle is a large, robust insect measuring 20 to 35 mm in length and 7 to 12 mm wide. It has a typical beetle shape and is shiny black with up to 20 white dots on its back. Larger white dots are usually arranged in parallel lines crossing the width of the body on the wings (elytra). Distinguishing features include the long, segmented antennae which alternate black and white or whitish-blue and are longer than the body. The legs will also be tinged blue or whitish-blue, especially for the first few days after emergence.

Why are they a threat?

  • The majority of Canadian broadleaf trees are at risk from the Asian long-horned beetle (ALHB), including all species of maple. They do not attack conifers.
  • Canada 's temperate climate is well suited for the establishment of the insect as the larva spends winters deep within the wood protected from harsh winter conditions.
  • The beetle has no known natural enemies within Canada 's forests.
  • Insecticides do not protect infested trees and only kill some beetles when applied to uninfested trees before attack.
  • The only way to combat the beetle is to identify, cut down, and burn or chip the infested tree.
  • Infested trees are also prone to secondary attack from other insects and diseases.
  • The beetles are believed to travel in wooden pallets or crates used to transport goods. Even though there are rules in place stipulating that crating material must not have insects in it or have insect damage, the increasing number of importers and goods coming into the country make these rules difficult to enforce.
  • Once established, the beetle is extremely difficult to eliminate. In New York State alone, millions of dollars have been spent trying to eradicate this beetle, and thousands of ornamental and shade trees have been lost. (Information from the Ministry of Natural Resources).

CFIA Asian Long-horned Beetle Fact Sheet

Gypsy Moth

Click here for the HCA's Gypsy Moth webpage

For more information on all invasive species in Ontario, including plants, fish, invertibrates, pathogens and forest pests, visit the Invaders page of Ontario's Invasive Species Awareness Program

Invasive Plants

Invasive plants are species that are not native to a region or country that have the ability to compete with and replace native species in natural habitats. There are several invasive plants that have a significant detrimental impact on native ecosystems in the greater Hamilton area.

The invasive plant species that can be found in Ontario include:

  • Amur, Morrow and Tatarian Honeysuckles (Lonicera maackii, L. morrowii, L. tatarica)
  • Common buckthorn and Glossy buckthorn (Rhamnus cathartica, Rhamnus Frangula)
  • Common Reed (Phragmites australis)
  • Dog-strangling vine (Vincetoxicum nigrum)
  • Eurasian Watermilfoil (Myriophyllum spicatum)
  • European frog-bit (Hydrocharis morsus-ranae)
  • Fanwort (Cabomba caroliniana)
  • Flowering Rush (Butomus umbellatus)
  • Garlic Mustard (Alliara petiolata)
  • Giant Hogweed (Heracleum mantegazzianum)
  • Japanese knotweed (Polygonum cuspidatum)
  • Norway Maple (Acer platanoides)
  • Purple Loosestrife (Lythrum salicaria)

Invasive Fish Species

There are several invasive fish species that can affect the health of not only the Great Lakes, but smaller lakes and other water systems. These are the invasive fish species currently found in Ontario:

  • Common carp (Cyprinus carpio)
  • Grass Carp (Ctenopharyngodon idella)
  • Bighead Carp (Hypophthalmichthys nobilis)
  • Silver Carp (Hypophthalmichthys molitrix)
  • Black Carp (Mylopharyngodon piceus)
  • Northern Snakehead (Channa argus)
  • Round Goby (Apollonia melanostoma)
  • Rudd (Scardinius erythrophthalmus)
  • Ruffe (Gymnocephalus cernuus)
  • Sea Lamprey (Petromyzon marinus)

Invasive Invertebrates:

  • Bloody Red Shrimp (Hemimysis anomala)
  • Fishhook Water Flea (Cercopagis pengoi)
  • Rusty Crayfish (Orconectes rusticus)
  • Spiny Water Flea (Bythotrephes longimanus)
  • Zebra Mussel (Dreissena polymorpha)