Beware Organic Poisons - and Hidden Ones

If you like the idea of growing native, you probably also like the idea of growing organic.  But what does organic gardening mean? Does it mean "no poisons?"  Unfortunately not.

Several complex chemical pesticides are considered "organic," because they are naturally found in plants or bacteria.  But that does NOT make them safe.  Astoundingly, produce can be grown using these poisonous substances and still be labeled "organic!"

Pesticides can sneak up on you.  A dear friend had been applying "systemic" to her roses for years. I asked her if she could do without the pesticide.  "What pesticide?"  She never realized she was applying systemic (i.e. long-acting) pesticides to her roses, not just fertilizers.  She is no dummy; those labels are tricky.  If you apply any commercial substance to your plants, please read the label with a magnifying glass! "Make your plant healthy" blends often have pesticides in the mix.  If it doesn't say "%N, P or K" after the chemical, assume it is a pesticide. (Or google the substance name...)

A native garden does not need pesticides.  It has natural bug defenses. I use harmless soap/oil sprays to wash off an infestation if I am feeling fastidious.  If the plant looks really ratty, I trim it. After all, a butterfly garden has to feed the caterpillars!

I do not treat my roses either.  I find that regular fertilizing and a weekly rinse-off in the spring leaves them "healthy enough."  Perfection is a harsh mistress; I don't work for her.  When a plant is truly infested, I remember the words of a master gardener friend:  "If it is infested, it was stressed."  Then if a soap bath and a little TLC won't cure it, I practice Darwinian Gardening (TM) and toss it in the compost heap.

If you have invested in a thousand acres of orange groves, you must save those oranges by any means necessary.  Monoculture is evil.  A commercial organic gardener I met at Esalen mentioned that he grows 70 different crops!  And decades of experience in keeping them healthy without chemicals.  As a home gardener, if a critter eats one plant, I figure out a non-chemical remedy, or grow something else.  I like knowing anything that grows in my yard is safe to touch and to eat, and that I am as welcoming to bees as I know how to bee.

Most pesticides, "organic" or otherwise, are thousands of times more poisonous to bugs than to mammals and birds.  As they should be!  But they are instant death to bees, frogs, and sometimes fish as well.  And the farmworkers who must apply them or work in treated fields get huge exposures.

Here is the rogues' gallery.

Pyrethrin(s), the most widely used "organic," is derived from some chrysanthemum plants.  From the Natural Resources Defense Council website:

When used by themselves, pyrethrins breakdown fairly quickly in the environment and can also be readily detoxified by most mammals. However, pyrethrins do pose a risk to cats because they lack the ability to process these chemicals and exposures can can cause tremors, twitching, convulsions, and death. 

Pyrethrins, especially when used in combination with chemical enhancers such as piperonyl butoxide, can be toxic to the human nervous system as well and can also cause allergic reactions and exacerbate asthma. [Note, when not used with enhancers they often stun insects rather than kill them.] EPA classifies pyrethrins as "Suggestive evidence of carcinogenicity but not sufficient to assess human carcinogenic potential." Signs of pyrethin poisoning may include coughing, wheezing, shortness of breath, runny or stuffy nose, chest pain or difficulty breathing. 

Several household bug-killing sprays, foggers, houseplant sprays, lice shampoos, and pet flea/tick control products contain pyrethrins, usually in combination with other chemicals. Using these products can expose you and your family.  Although pyrethrins break down quickly in sunlight, indoors they can persist in carpet dust for up to two months. When chemicals are present in floor and carpet dust, young children may ingest the chemicals after putting their hands in their mouths.

Rotenone, another plant-derived pesticide, is very unselective.  It was used by indigenous South Americans to poison fish.  While it decays quickly in warm conditions, it can produce Parkinson's symptoms in mammals. 

Nicotine was formerly used as a pesticide but due to its high toxicity to mammals it is now banned in the U.S. for that use.

Neem oil is a traditional Indian medicine that can be poisonous to humans in less than gram quantity.  It has simply not been tested enough to know its toxicity to animal life and its persistence in the environment.

Spinosad, derived from bacteria, is a new insecticide on the market.  It is a chemical, not a bacterium, despite some deceptive labeling.  Spinosad is about as poisonous to mammals and birds as sugar, so it is a great choice for treating head lice and fleas.  But it is still death to bees.  "Cap'n Jack's DeadBug Brew" and "Monterey Garden Insect Spray" are common brands.

Natural substances like sulfur, boric acid and "dormant oil" (simple oils) are used for particular applications.  Be aware that they may build up over time.

Nutrition Diva (Monica Reinagel) did a podcast on avoiding pesticide exposure.  She has learned that people who exert trouble and expense to buy organic often go about their homes and gardens spraying insecticides with great abandon.  They are oblivious to the fact that their exposures are many times what any residue in conventionally-grown food would have given.  On that front, I am still working to get my neighborhood association to stop random monthly pesticide dousings in the common areas, which accomplish nothing.  Wish me luck.

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