Rotenone is a “naturalpesticide/piscicide. Natural in that it is an extract from a plant - a real life plant, not a synthetic compound chemical. In quotes because what does that mean anyway? The Rotenone molecule is known to be toxic to cold-blooded animals and thought to be relatively non-toxic to mammals. Rotenone is used in some jurisdictions in what is called “organic gardens” despite the fact that it causes allergies and dermatitis and was been implicated in the year 2000 in the acquisition of Parkinson’s disease like symptoms in intravenously exposed rats. Of special concern is the fact that organic produce is felt by some to be safe to eat despite recent applications of rotenone.

Other jurisdictions and individuals no longer consider Rotenone to be “organic” or safe for human consumption due to possible human harm and the broad-spectrum action that kills beneficial insects as well as pests.

Rotenone can be extracted from over 70 plants; most commonly used today is the root of the tree Derris.

Historically Rotenone-like compounds have been used for millennium and in multiple cultures to capture fish and since medievall times as a powdered pesticide. As a piscicide the plant was/is pounded in some way and placed in the body of water containing the desired fish. The fish lose the ability to oxygenate their blood and float to the surface. Despite being “poisoned” the fish were/are then eaten by the indigenous peoples. As a pesticide, the dry plant was ground up and sprinkled about the home or body of the person being treated for multiple ailments.

The active compounds are relatively non-harmful in mammals when ingested because they break down in the gut to harmless compounds. They are however harmful to mammals if inhaled, consequently Rotenone is a worry to persons who use it frequently, especially if in a concentrated powder form.

The EPA classifies Rotenone as highly toxic or slightly toxic depending on concentration. The World Health Organization classifies it a as moderately hazardous. Dermatitis, allergies and possible Parkinson's like symptoms are potential problems in mammals.

Vitamin K and alkaline solutions are antidotes in mammals. Death is the consequence to fish. The piscidal properties are easily reversible (if desired) with the quick use of fresh water immersion or the addition of potassium permanganate to the poisoned water. This is important because Rotenone is sometime applied to check fish population samples, not just to kill off undesirable fish. Rotenone is slightly toxic to birds. It is not toxic to bees if applied alone but is frequently combined with Pyrethrins (another “organicpesticide) and in this combination is deadly to bees. Rotenone taken up by plants degrades quickly and is relatively harmless to the plant but does make the plant and any animals that ingest it more photosensitive than usual for a short time.

Rotenone degrades quickly in heat and when exposed to sunlight. In both water and soil it is usually completely degraded in 3 – 6 days depending on ambient temperature. It is not thought to contaminate groundwater.

Rotenone is used in veterinary medicine as a shampoo to manage mange in dogs and body mites in cats. It is also used to manage cattle grubs, and sometimes for fleas, lice, and ticks. Rotenone has been used in human medicine as well. It was used topically to manage parasites. In the 70s Rotenone was used in humans for its “anti-tumor” properties because its mode of action is antimitotic (restricting the division of cells and therefore bad for most tumors which consist usually of rapidly dividing cells).

Despite the apparent “safety” of ingesting rotenone poisoned fish as evidenced by historical use and the known detoxification in the mammalian gut and the relatively frequent modern use of Rotenone to manage fisheries the dead fish are not considered edible in the US. Not that I would want to eat them but this really highlights the schizoid attitude that Rotenone contaminated food plants are considered fine to eat. Rotenone is only restricted by the EPA when used on fish or cranberries (cranberries are grown in wetlands).

Clearly, although a plant extract and not a synthetic compound, Rotenone is not categorically safe for humans, other mammals or birds. Obviously it is not safe for insects or fish (friend or foe). “Organic” is such a silly word; really it only means carbon based. We need to look beyond the organic labeling and take appropriate precautions when using or ingesting this chemical as well as other organic pesticides.

SOURCES: pyrethrins-ziram/rotenone-ext.html