Twelfth rule : Use low-impact pesticides as a last resort

What should you do if one of your plants looks sick? Start by examining it closely to properly identify the cause of the problem. If you don't see any particular insect pests or diseases, make sure that the plant isn't just suffering from inadequate growing conditions (insufficient light or water, nutrient deficiency, overfertilizing, pH too high or too low, frost or wind damage, etc.). If an insect pest or disease is to blame, first assess the scope of the problem and decide whether you actually need to do something about it. Given the right growing conditions, strong plants can withstand a few insects or pathogens.

If you do decide to act, start by using cultural, physical, mechanical and biological (see sidebar) methods. If you're not satisfied with the results and you decide that you have to use pesticides, choose ones with a low impact. They are not very toxic in the short or long term for human health and the environment. They break down quickly and most of them destroy harmful organisms without interfering much with useful organisms.

Pesticide usage is governed by the Pest Management Regulatory Agency (federal), the Pesticides Management Code (provincial) and municipal by-laws, including City of Montréal By-law 04-041 on the use of pesticides. Check with your municipality before using any product.

Read and follow the instructions on the label before getting started. Pay careful attention to dosages, application methods, safety instructions and treatment intervals. Finally, keep an eye on the plant afterward and adjust your cultural methods accordingly.