Pesticides (including Herbicides)

A pesticide is the general term used for substances that include insecticides, herbicides, fungicides, algicides, miticides and rodenticides. There are more than 7,000 pesticides registered in Canada for use in homes, gardens, on golf courses, on forests, and along rail and hydro corridors.

In Canada, pesticides are regulated by Health Canada under the Pest Control Products Act and Pest Control Product Regulations. Scientific assessment, enforcement, education and information dissemination are shared among federal, provincial and municipal governments. Most pesticides are intentionally toxic to the target organisms, however some pesticides have been banned in Canada, (DDT, and 2,4, 5-T) as they are also toxic to non-target species and are persistent in the environment.
Pesticide concerns
  • Non-selective pesticides may affect beneficial insects, birds, frogs, fish etc.
  • If used in aerial sprays, may drift off target
  • Indirect effects on fish include loss of canopy (and shade) over streams, and reduction of food organisms on aquatic or streamside vegetation.
  • Resistance may develop in weed or insect species. 
  • Inert additives – surfactants, solvents, lubricants, solubilizers and suspension agents- are generally not listed on labels, (to protect manufacturing trade secrets) yet many have adverse side-effects. 
  • Persistence in the environment of active ingredients, additives and metabolic  by-products.
Ten percent of the pesticides sold in Ontario are used in the forest industry. One of the most common pesticides used in the forest industry is the herbicide glyphosate – probably know best as “Roundup”. It is also sold to farmers and gardeners under the names Vision, Vantage, Rodeo, Accord, Wrangler, Erase etc. It is a non-selective herbicide and is used to kill broad-leaved plants, grasses and sedges.

Issues specific to glyphosate 
  • US EPA has found glyphosate to be “extremely persistent” and slightly toxic to birds, aquatic vertebrates, and fish and moderately toxic to embryo and larvae. 
  • Surfactants added to Roundup have been found to be much more toxic than glyphosate. 
  • It has been found in surface and ground waters and binds to some soils.
  • Non-specific, can also affect raspberries, blueberries etc.
  • Used for vegetation control, it results in decreased habitat complexity causing a decrease in invertebrate populations and songbird numbers.
Glysophate drift damage to apple tree and  cucumber plant 

Forest "Pests"
Insects and disease are a natural part of forest eco-systems. Researchers studying forest ecology at the Ontario Forest Research Institute (OFRI) in Sault Ste. Marie note that Armillaria root disease has evolved with Ontario trees and acts as a forest thinning agent – taking out weaker trees and freeing up space for more vigorous trees. Ice and wind storms clear out deadwood and the rotting branches on the forest floor release nutrients for younger trees to use. Standing and fallen dead trees provide habitat for many species of plants and animals.
Above: effects of Armillaria root disease include root rot, dying trees, trees susceptible to windthrow
Many forest pests are well known to Ontarians. Some species are native to our forests such as forest tent caterpillars and spruce budworm, and some are imported or ‘exotic’  species such as Gypsy moth and Dutch elm disease.  White pine blister rust - an aggressive fungal disease that was imported from Europe, and recently the brown long horned beetle – imported into Ontario via wood packing crates are some of the more recent insect pests that may affect forest health.

The Forest Management Planning Manual (FMPM) and pest management:

Background Papers Prepared for Northwatch Forest Project Symposium on Herbicide Use in Forest Management

Other Background and Research Papers related to Herbicide Use in Forest Management

Herbicide Use in Forest Management - Northwatch Forest Project 2006 Fall Presentations Program

MNR Planning Info         Science & Ecology Links        Viewpoints Forest Management Guides, Manuals & Laws

MNR Planning Info

Science & Ecology Links


Links to Forest Management Guides, Manuals and Laws

Please email us with your suggestions for other important links to be added to this page.
Are you looking for a link or document and can't find it? Email us,and we'll help you look.

Back to Issues Page Index

Back to FMP Home Page