How so Don? I don't understand.
The heavy duty pesticides are neurotoxins, toxic to the brain and nervous system. They don't kill people right away, but too much exposure over the years leads to all kinds of problems.
The other thing I don't like about them is they kill all insects, even beneficial ones. Then, unless you keep applying it, your garden ends up vulnerable to massive insect damage when one species takes over. You're better off encouraging as much life, insect and microbial (not woodchucks!) in a lawn or garden and then using gentler pesticides that are targeted to certain classes of insects and which break down faster, like BT, or soap/pepper sprays.
I can see how if you're a professional farmer and your livelihood depends on getting the crop in that hey are sometimes necessary, but I think it's crazy that people pay money to the ChemLawns of the world to pour pesticides, weed killers, and chemical fertilizers on a lawn. Why would anyone want a lawn without insects? Which means without birds, too. I have seen lawns that were completely dead, no insect sounds, no birds, and a plant monoculture of one species.
end of rant...