My understanding of the law is that ANY product applied to control a weed or pest, regardless of its intended labeling, would be considered a pesticide. This would mean if you are applying corn gluten meal with the intention of controlling weeds, you are using it as a pesticide, and therefore should be licensed to do so. The same goes for home brews and Jerry Baker remedy's. I recall looking into this a year or two ago, and thought I remembered that to be the case. I could be wrong, but I would look into it further for more clarification.