Editing Insecticide (section)

===Plant extracts===
Most or all plants produce [[Plant defense against herbivory|chemical insecticides to stop insects eating them]]. Extracts and purified chemicals from thousands of plants have been shown to be insecticidal, however only a few are used in agriculture.<ref name=":11">{{Cite journal |last=Isman |first=Murray B. |date=2020 |title=Botanical Insecticides in the Twenty-First Century—Fulfilling Their Promise? |url=https://doi.org/10.1146/annurev-ento-011019-025010 |journal=Annual Review of Entomology |volume=65 |pages=233–249|doi=10.1146/annurev-ento-011019-025010 |pmid=31594414 }}</ref> In the USA 13 are registered for use, in the EU 6. In Korea, where it is easier to register botanical pesticides, 38 are used. Most used are [[neem oil]], [[chenopodium]], [[Pyrethrin|pyrethrins]], and [[azadirachtin]].<ref name=":11" /> Many botanical insecticides used in past decades (e.g. [[rotenone]], [[nicotine]], [[ryanodine]]) have been banned because of their toxicity.<ref name=":11" />