>How is only allowing "natural" pesticides not appealing to the naturalistic fallacy? If you really care about improving ecosystems, you should be using the bes

>How is only allowing "natural" pesticides not appealing to the naturalistic fallacy? If you really care about improving ecosystems, you should be using the best knowledge and techniques available. Because “what is best” is not always obvious, especially when something is relatively new. Pesticides in general are prohibited, and if the conditions for an exception are met, then the criteria for selecting a pesticide are that it based on precaution. It’s not that “natural stuff is ok and synthetics are not” otherwise the organic program would permit natural substances such as rotenone that have been shown to be harmful. The perspective is that synthetic substances are also subject to the precautionary principle, and should be studied to determine the safety and efficacy before they are permitted. Much of what we call “organic” is just “the way things were routinely done before the invention of selective herbicides” and when credible concerns about those substances and practices were raised, the rules were changed to reflect that understanding. >You'd be overgeneralising to say every modern pesticide had this problem though. Agriculture is a broad field (!) and one can usually find exceptions somewhere to blanket statements. Is there a reason why some selective herbicides wouldn’t create selective pressure and thereby select for weeds that are resistant to that substance? I think that’s how evolution works and that’s the basic mechanism here. You haven’t seen resistance for the newer substances simply because there hasn’t been enough time for resistance to develop. Why is this not a problem for pesticides used in organic farming? Probably because pesticides used in organic farming are not selective which means they will damage/kill your crops as readily as they will competitor organisms. Modern herbicides are selective, which means they kill the weeds and leave your crops alone, because the crops have resistant traits. These resistant traits are the ones that evolve in the weeds.