Lots of them [1]. Anything you buy at the store labeled "organic" could involve any of these substances, among others. In addition, because organic pesticides are less effective per unit, much more is applied to get the same benefit. [2]

[1] http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&SID=9874504b6f10...

[2] http://blogs.scientificamerican.com/science-sushi/httpblogss...

Nicotine, rotenone, pyrethrins are just a few examples [1]. They are mostly derived from other plants so are regarded as organic although they can be quite toxic to humans.

[1]http://www.colostate.edu/Dept/CoopExt/4dmg/VegFruit/organic....

Nicotine is also believed to be an issue with declining bee populations.

Off the top of my head: Bt proteins, copper. There are many more, you can easily google and find a long list.

And yes, that's the same Bt that's in Bt crops, by the way (proteins from Bt bacteria). Organic farmers use it in a spray. It's a natural substance, and they argue the spray causes less resistance than the GM varieties. I really don't have the domain knowledge to say whether they're right.

Not all organic farmers are the same, and over time the meaning of 'organic' has been diluted. Smaller, more idealistic organic farmers mostly don't use pesticides, but there are large commercial organic growers out there who meet the bare minimum for certification and will use whatever pesticides are allowed.

From the piece I linked to, http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&SID=9874504b6f10...

When "gardening", you can probably do just fine without using pesticides. But when you farm crops as a business, you have to do something.

> But when you farm crops as a business, you have to do something.

Several family farms at my local farmers market claim their crops are pesticide free. Now granted they are probably 10s of acres, not 1000s of acres, but they are still making a living.

Any chemical that is naturally occurring is considered organic. To be specific here: https://www.ams.usda.gov/rules-regulations/organic/national-... is the USDA's list of chemicals that can be used and still be labeled organic.

but why do you garden with transgenics! It's unnatural!