The City of Toronto and outlying townships are working to monitor and control the infestation of invasive insects which are threatening large tree populations. The most prevalent and widespread are the Asian Long-Horned Beetle and the Emerald Ash Borer. See the links below for information on these pests as well as governmental policies, programs, task forces, and regulations currently in place.
Several townships have posted additional information pertinent to the area. This includes information about pests not as widespread as these two but a concern in the area (e.g. gypsy moth in Richmond Hill):
All sightings of these pests should be reported to the Canadian Food Inspection Agency by contacting a local CFIA office or calling 1-800-442-2342.
Asian Long-Horned Beetle
The Asian Long-horned Beetle (ALHB) is a forest insect pest native to China and Korea that arrived in North America in the late 1990s and attacks a variety of native hardwood species. It is believed that ALHB arrived in North America in untreated wooden packing materials, such as crates, from China.
The beetles feed on the leaves and twigs of trees. Damage on young shoots causes them to wither and die. Signs of advanced infestation include leaf yellowing and wilting, pre-mature leaf drop, branch die-back and tree death. Preferred host trees include birch, elm, hackberry, horsechestnut, maple, mountain ash, poplar, silk tree, sycamore or london plane tree, and willow.
The City of Toronto, the City of Vaughan, and the Regional Municipality of York are jointly participating in the Asian Long-Horned Beetle Intergovernmental Talk Force since April, 2004. The task force also includes the participation of the provincial government and the local conservation authority.
Emerald Ash Borer
The Emerald Ash Borer (EAB) is an invasive insect native to eastern Asia that attacks and eventually destroys healthy ash trees (genus Fraxinus, does not include Mountain ash). It was discovered in 2002 in Michigan and Ontario and likely came here in a shipment of untreated wooden packing material from Asia.
The adult beetles feed on foliage but cause little damage, until they lay eggs on the bark. The larvae feed on the inner bark of ash trees, destroying the layer that is responsible for transporting nutrients and water throughout the tree. When this occurs an otherwise healthy tree may die in 2 to 5 years. Damage to the tree will be apparent under the bark, where distinctive S-shaped galleries will appear as they feed.
Unfortunately signs of damage are usually only apparent once a tree is already heavily infested. Signs include loss of green colour in the highest leaves, and thinning and die-back of the crown. As the infestation continues the tree may develop sprouts from the roots, trunk or branches in an effort to find new ways to transport nutrients. Another sign are D-shaped holes, which the adults create when exiting the tree to fly on to their next victim.