Organic pesticides aren’t necessarily more sustainable than synthetic
http://nutsci.org/2010/06/24/organic-pesticides-arent-always-more-sustainable-than-synthetic/
"It would seem illogical that organic compounds are all more sustainable than synthetics, or vice versa. The term organic has a health halo, biasing many people toward believing organic growing techniques are best for the environment. Ive already covered analyses suggesting that there isnt enough evidence that suggests organic foods are better for your health, so is the higher cost justified by a lessened environmental impact? Bahlai et al. just published a paper suggesting that the dichotomous classification of organic and conventional is not optimal for sustainability, we must evaluate pesticides individually.
According to the authors, sustainable agriculture programs put an emphasis on the development of organic and natural insecticides to control pests, with the assumption that they are safer on the environment compared to synthetics. Public opinion also leans toward this assumption as well. The various practices (organic, conventional, or integrated) have been studied producing different results on sustainability. Differences in methodologies, practice classifications, and a number of other variables make it difficult to draw conclusions at this point. Importantly, they note:
each system is characterized by a suite of practices which are ideologically, rather than empirically defined, these systems are not mutually exclusive from each other, and vary from region to region depending on regulations. Because of these variations, generalizations about the overall sustainability of one system over another are never universal.
Organic farms do indeed (generally) use pesticides, they just arent synthetically made, while conventional farms can use both natural and synthetics.
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Well, I found this piece to be well done, and quite interesting...