Pesticides used in organic farming have to meet organic input criteria here. So copper sulphate and slaked lime is accepted for some spraying purposes (as an example). Roundup, and similar, is not accepted. I'm not sure on the residue in Canada, I can only speak for the people I deal with (who are the farmers of the organic produce I buy). I don't know if my local supermarket has organic fruit and vegetables - I suppose they would. It's sad that you have so much pesticide spray - hardly organic then :silent:
According to that wikki article, rotenone (the ingredient in roundup) and also pyrethrins and azadirachtin are allowed on organic foods. I guess Im not so surprised about roundup - its half life is very short, but Im a bit surprised about the pyrethrins and azadirachtin because of the damage to beneficial insects, especially bees.
In organic farming synthetic pesticides are generally prohibited. A chemical is said to be synthetic if it does not already exist in the natural world. But the organic label goes further and usually prohibit compounds that exist in nature if they are produced by Chemical synthesis. So the prohibition is also about the method of production and not only the nature of the compound.
A non exhaustive list of organic approved pesticides with theirs Median lethal dose
Copper(II) sulfate is used as a fungicide and is also used in conventional agriculture (LD50 300 mg/kg). Conventional agriculture has the option to use the less toxic Mancozeb (LD50 4,500 to 11,200 mg/kg)
Boric acid is used as stomach poison that target insects (LD50: 2660 mg/kg).
Pyrethrin comes from chemicals extracted from flowers of the genus Pyrethrum (LD50 of 370 mg/kg). Its potent toxicity is used to control insects.
Lime sulphur (aka calcium polysulfide) and sulfur are considered to be allowed, synthetic materials (LD50: 820 mg/kg)
Rotenone is a powerful insecticide that was used to control insects (LD50: 132 mg/kg). Despite the high toxicity of Rotenone to aquatic life and some links to Parkinson disease the compound is still allowed in organic farming as it is a naturally occurring compound.
Bromomethane is a gas that is still used in the nurseries of Strawberry organic farming
Azadirachtin is a wide spectrum very potent insecticide. Almost non toxic to mammals (LD50 in rats is > 3,540 mg/kg) but affects beneficial insects.