I think you under-estimate the pesticide regimen comerical farms use (I doubt your neighborhood gardener could get there hands on some of them). Though you are probably correct, small gardens aren't really an efficient way to grow food.

I'm not a farmer but this description of farming from the end of last century stuck in my mind.

https://www.nytimes.com/1998/10/25/magazine/playing-god-in-t...

"I asked him to walk me through a season's regimen. It typically begins early in the spring with a soil fumigant; to control nematodes, many potato farmers douse their fields with a chemical toxic enough to kill every trace of microbial life in the soil. Then, at planting, a systemic insecticide (like Thimet) is applied to the soil; this will be absorbed by the young seedlings and, for several weeks, will kill any insect that eats their leaves. After planting, Forsyth puts down an herbicide -- Sencor or Eptam -- to ''clean'' his field of all weeds. When the potato seedlings are six inches tall, an herbicide may be sprayed a second time to control weeds.

Idaho farmers like Forsyth farm in vast circles defined by the rotation of a pivot irrigation system, typically 135 acres to a circle; I'd seen them from 30,000 feet flying in, a grid of verdant green coins pressed into a desert of scrubby brown. Pesticides and fertilizers are simply added to the irrigation system, which on Forsyth's farm draws most of its water from the nearby Snake River. Along with their water, Forsyth's potatoes may receive 10 applications of chemical fertilizer during the growing season. Just before the rows close -- when the leaves of one row of plants meet those of the next -- he begins spraying Bravo, a fungicide, to control late blight, one of the biggest threats to the potato crop. (Late blight, which caused the Irish potato famine, is an airborne fungus that turns stored potatoes into rotting mush.) Blight is such a serious problem that the E.P.A. currently allows farmers to spray powerful fungicides that haven't passed the usual approval process. Forsyth's potatoes will receive eight applications of fungicide.

Twice each summer, Forsyth hires a crop duster to spray for aphids. Aphids are harmless in themselves, but they transmit the leafroll virus, which in Russet Burbank potatoes causes net necrosis, a brown spotting that will cause a processor to reject a whole crop. It happened to Forsyth last year. ''I lost 80,000 bags'' -- they're a hundred pounds each -- ''to net necrosis,'' he said. ''Instead of getting $4.95 a bag, I had to take $2 a bag from the dehydrator, and I was lucky to get that.'' Net necrosis is a purely cosmetic defect; yet because big buyers like McDonald's believe (with good reason) that we don't like to see brown spots in our fries, farmers like Danny Forsyth must spray their fields with some of the most toxic chemicals in use, including an organophosphate called Monitor.

''Monitor is a deadly chemical,'' Forsyth said. ''I won't go into a field for four or five days after it's been sprayed -- even to fix a broken pivot.'' That is, he would sooner lose a whole circle to drought than expose himself or an employee to Monitor, which has been found to cause neurological damage.