No matter where or how you garden, pests (including insects, fauna such as rabbits and deer and diseases) will find your garden. Techniques such as crop rotation and companion planting are very effective and cheap ways of controlling pests but there are instances when further intervention may be required; when you're staring a new garden or when a new pest arrives in your area for example. When you experience these and other similar situations, pest pests may get out of control before your companion plants have established etc. and so pesticides can provide a useful short term solution. Organic pesticides are particularly useful because many of them can be made from everyday materials that you have in your home so they are usually cheaper than synthetic pesticides. They are also better for the environment and are often safer than synthetic pesticides.
Pesticides mean different things to different people but a pesticide is any product that kills a pest - be that an insect pest, fungus or other form of pest. Many pesticides are also preventative.
Just because an organic pesticide is made from edible materials or other materials that you may use everyday, does not mean that they cannot be harmful. Organic pesticides can still kill beneficial insects if they're not used carefully. They can also cause skin and eye irritation and they should never be ingested.
In this part of the Garden Realm website you'll find information on a variety of organic pesticides that you can either make yourself at home or are available commercially.