There's nothing like a friend to watch over you. That's just as true with plants as much as it is in our world, possibly more! Very few of our home grown beauty's have what it takes to defend themselves from all attackers but each and every plant has an in-built defence against something.
As an axample, sowing alternate rows of carrots and onions can confuse both the carrot fly and the onion fly.....now that's what I call working together.
There are many instances of this in nature and it's becoming more and more important in this chemically polluted world to use natural defences rather than man-made pollutants.
Do you have a question or input on companion planting?