I've been reading about companion planting lately, as a method of pest control. For example, I was told that by planting alternating rows of corn and sunflowers, I won't have much (if any) of a pest problem for those two crops.
It seems that the critters that like sunflowers, dislike corn and the cooties that like corn hate sunflowers. I'm going to research this a bit more and see if I can work it into our garden this year.
I'm still going to get the Mantises, but I will definitely be giving the companion planting a go.
Now I just need to find a plant that drives away the flies responsible for apple maggots...