I have two companion/trap-crop stories to share.

Background - two years ago I did not have any companion planting and there were aphids all over my apple trees. And then:

1) Last year I grew lots of nasturtiums. They got covered with aphids mostly because I was lazy and never got around to spraying them. But before I sprayed, I noticed that there were no aphids on my apple trees. So I let them be and while the nasturtiums suffered, I didn't have to spray the apple trees. Eventually ladybugs showed up but it was a little too late for the nasturtiums.

2) This year I have a big bunch of yarrow growing. So far this year they are covered with aphids. The yarrow doesn't seem to be suffering much but I can't say for sure they wouldn't be much bigger without their little swarm of pests. And wouldn't you know - no aphids on the apple trees. This year I also noticed that were lots of ladybugs on the yarrow and now lots of ladybug larvae on both the yarrow and the apple trees.

Moral of the story (so to speak) lazyness leads to accidental companion planting leads to ladybugs.

Cindy