Generally speaking, GMO crops are lower-yielding than heirloom varieties, unless you apply the requisite fertiliser, pesticides and herbicides. With the addition of those chemicals the GMO crops perform better since they are more tolerant of excess nutrients, and better able to convert the excess nutrients into the desired product.
So if you want to reduce reliance on chemicals (which I do), then GMOs are a bad idea?
Personally I'm a big fan of projects that use more natural ways of fighting weeds and pests. I've read about some very effective programs that reduced pests by planting a specific plant around the crop fields, or (re)introducing a predator of that pest.
