The lone voice of horticultural reason

“Organic pesticides don’t harm the environment.”

Unequivocally false.

We’re talking pesticides, and on the organic side of the equation, this means things like insecticidal soaps, Bt (Bacillus thuringiensis), pyrethrum (from African mums), and rotenone (pea family). You’ll see these listed as the active ingredients in all sorts of organic pesticides.

What is important to remember is that a pesticide contains a chemical that is a poison, whether the chemical is organic or synthetic. “Organic” means the chemical is derived from the earth, its deposits, or its plants. “Synthetic” means the chemical is made by evil Republicans in lab coats. Either way, the chemical kills bugs.

All chemicals used in pesticides are rated on a scale called EIQ, or Environmental Impact Quotient. The chemicals are tested for range of toxicity, or what it is they will harm or kill. Let’s say the chemical doesn’t harm people in anything short of beer-chugging amounts; that might merit a 2. But an ounce of the stuff in a stretch of stream kills all the fish; give it a 10. The chemicals are tested for how long they stay in the soil, in plants, if they kill bees, if they kill worms, etc.

Here are some interesting EIQs:

Bt (organic) 13.5
Acephate (synthetic) 17.9
Soap (organic) 19.5
Carbaryl (synthetic) 22.6
Malathion (synthetic) 23.2
Rotenone (organic) 33.0
Sabadilla (organic) 35.6

You can see that some organic chemicals-and all of these are in use-have a higher Environmental Impact Quotient than some synthetics, notably the synthetic Carbaryl (which is Sevin), one of the most commonly used synthetic pesticides in the world.

My point is not to knock organics. I try not to use any pesticides in my garden. The best way to avoid using pesticides is to keep a clean and tidy garden, keep your plants watered, and keep them healthy. I’ve had stretches close to ten years without having to spritz anything that’s a poison. But once in a while an infestation can get pretty ugly. I’ll first use an organic insecticide, usually a soap, in moderation and exactly according to instructions. A very limited use and most often the job is done.

But organic pesticides have very real drawbacks. Most of them have broad spectrums, meaning they kill beneficial insects (just like those dangerous synthetic chemicals). They are not as thoroughly tested as synthetics. Batch strength can vary. And, perhaps most dangerous of all, they are perceived by the gardening public as safe. Nothing could be farther from the truth.

Pyrethrum is a widely used organic chemical, used by organic vegetable growers, and used by commercial industries as the toxin in sprays designed to kill everything from wasps to asparagus beetles. It’s also a nerve toxin, and extremely dangerous to infants. Never use wasp spray around an infant, or you will learn just how dangerous some of Mother Earth’s little secrets can be.

Safe/dangerous are always relative, anyway. 100 years ago, there were no synthetic, man-made chemical pesticides in use, not in gardening, not in agriculture, not anywhere. The big pesticide used across the land was 100% organic. It was lead-based.

Don Engebretson
The Renegade Gardener