About 10 000 species of insects and mites, and an equal number of diseases, that attack woody plants in Ontario have been identified. More than 90 per cent of those pests and diseases occur in limited numbers and as such do not threaten the health of plants.
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Birch Leafminer damage |
Artificial control of these is often for cosmetic purposes. Pesticides should be applied only against specific pests, and at a time when their abundance or the injury they cause makes spraying justifiable. With most pests only one stage in the lifecycle is controlled with a particular pesticide. Therefore, proper timing of treatment is very important. Calendar dates given in the text are meant to be used as a general guide; the development of a pest will vary from place to place and from year to year, depending on the weather.
All pesticides sold or used in Canada must be registered under the Pest Control Products Act, administered by the Pest Management Regulatory Agency of Health Canada. The registration states the type of use (restricted, commercial, domestic), the pests against which the material may be used, the rates and timing of application, and precautions for use. Registered pesticides are, in turn, scheduled (or approved) for sale and use in Ontario by the Ontario Pesticides Advisory Committee, under the Pesticides Act, administered by the Ministry of the Environment. Materials mentioned in this publication are among those presently approved for use by the general public; they are available at most nurseries, garden centres, and hardware stores. When properly handled they present little hazard to the applicator or the environment.
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