Integrated pest management, also known as IPM, is a system that combines biological, cultural, physical and chemical strategies to control pests. In plain English, that means using the easiest, least environmentally harmful, cheapest methods first and using more expensive, toxic methods only as a last resort.

Careful observation or crop monitoring is the first and most important step in IPM. You have to know exactly what pest you're dealing with, when it appears, how many you have and on what plants. For example, after you can recognize aphids, you may find them on a few rose buds on a single plant in the front lawn or covering every bush in your prize-winning garden. It may be the beginning of your gardening system or near the end. How you choose to control the aphids - or whether you choose to control them at all - depends on all these factors and more.

Integrated pest management strategies are like a series of steps. The first steps are the least toxic and the least harmful control methods. The most potentially toxic controls are last resort steps.

Cultural control: Giving plants optimal growing conditions - soil fertility, water, light and freedom from competing weeds - is the key to this first step. Other good cultural practices include using pest- and disease-resistant varieties and crop rotation, which means moving particular crops to new parts of the garden each year.

Crop sanitation: Keeping pests and diseases out of the garden in the first place is more than half the battle won. Inspecting new plants, cleaning your tools, eliminating weeds and using best watering practices help prevent the spread of potential problems.

Mechanical control: Prevent pests from getting on your plants by covering them with special fabrics or using hot water, air fire and the heat of the sun to kill them without poisons. Simply knocking pests into a can of soapy water does the trick, too.

Biological control: Every pest has a natural control, whether it's predator or disease. You can buy and release many of these control organisms or encourage the ones that already exist around your garden.

Chemical control: As a last resort, apply the least toxic pesticides. The best ones target only the pest and don't affect the innocent bystanders, such as bees, spiders and other beneficial insects. These pesticides also don't hang around in the environment where they can continue to affect other organisms long after their use.

Another factor that farmers - and you - must consider is how much pest or disease damage you can tolerate. Perfection comes at a very high price. Even farmers who must make a living or go bust based on the success of their crops have what they call an economic threshold, when the cost of the damage exceeds the cost of control. They expect to lose a portion of the crop completely and probably have another portion somewhat blemished. For them, it's an economic reality, but for most home gardeners, it's a matter of accepting less than perfection on 100 percent of your flowers and vegetables.