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Chemical Tools

With integrated pest management, chemical pesticides should only be used as a last resort. Combined fertilizer and pesticide products are not recommended as they spread pesticides over the entire area instead of just in the location where treatment is needed.

When using a chemical pesticide

  • Choose the least-toxic pesticide which specifically treats the insect or weed that is causing the problem.
  • Ensure the chemical product will not harm surrounding plants or the plant with the infestation.
  • Purchase only small amounts of ready-to-use pesticides.
  • Apply the pesticide only in the location where there is an infestation.
  • Always read and follow the label directions carefully and use the proper safety precautions as specified on the label. Go to Health Canada's Pest Management Regulatory Agency's website for more information about responsible pesticide use.

Reduced Risk Products

Here are some biological and least-toxic pest control products to consider if other tools in your IPM toolkit are not sufficient.

  • Acetic acid This clear, colourless liquid has a sharp vinegar smell. (Typically vinegar is about 4-8% acetic acid.) Acetic acid is marketed under various trade names as a non-selective weed and grass killer.
  • Bacillus thuringiensis (Bt) This is a naturally occurring soil-borne organism. To work, this insecticide must be ingested by the larva stage of certain insect pests such as caterpillars, loopers, and garden cut worms. As well, different formulations of Bt products are used to control certain pests (Bt.i and Bt.k control mosquitoes and cankerworms respectively.)
  • Bordeaux mixture and other sulphur compounds These chemicals are fungicides consisting of cupric sulfate and lime in water; they are used to control certain fungus problems on plants.
  • Dormant and Horticultural Oils These highly-refined oils are mixed with water and applied in the fall or early spring on plants, shrubs and small trees to control over-wintering pests such as scale insect and other insect egg masses. The oil suffocates the insects.
  • Ferric phosphate This compound containing iron (ferric) and phosphate is a molluscicide used to control slugs and snails. Herbicidal soaps Non-selective contact herbicide made of potassium salts and naturally-occurring fatty acids that are effective on some weeds.
  • Insecticidal soaps Insecticidal soaps contain potassium salts and naturally occurring fatty acids. They are known as contact insecticides, miticides or fungicides and are effective against soft bodied insects and mites such as aphids, thrips, white flies, spider mites, ants, and powdery mildew fungus.
  • Lime sulphur This compound is a mixture of lime and sulphur and is used as a fungicide, miticide and insecticide. It helps control mites, certain insect eggs, and fungi such as powdery mildew, rust, and brown spot.
  • Pheromone traps These traps use synthetic and/or natural chemicals to sexually attract insects to the trap where they are contained.
  • Pyrethrum (pyrethrin) Pyrethrins are produced by certain species of the chrysanthemum plant and are used as a contact insecticide to control a number of different insect pests.
  • Silica dioxide (Diatomaceous earth) This scarifying insecticide contains the fossilized remains of diatoms (microscopic hard-shelled creatures found in water thousands of years ago.) Diatom fossils have sharp spines that injure and kill exoskeletal insects, but not animals with internal skeletons.
  • Sticky media These traps include flypaper and similar sticky substances that capture insect pests.