ChewsWise Blog

ChewsWise Blog

What about those Organic Pesticides?

At an organic conference I attended last fall, I heard a farmer from the Central Valley of California, new to organic farming, bemoan the lack of organic-approved pesticides for production. "You just see aphids wipe out the crop," he said.

"I call that first generation organics," one industry veteran sitting next to me said. "They are just looking for replacements to the chemicals they use. They don't understand that what they really have to do is learn an entirely different method of farming."

A few "natural" pesticides are allowed under organic regulations, such as Rotenone, Pyrethrins (pdf) and Neem oil, and while they break down quickly when exposed to air or light they have various levels of toxicity. (Rotenone is the most controversial). The advocacy group, Beyond Pesticides, notes: "It is important to remember that just because a pesticide is derived from a plant does not mean that it is safe for humans and other mammals or that it cannot kill a wide variety of other life." (This was updated to note that Rotenone is no longer registered with the EPA, as a certifier pointed out in the comments section below).

A farmer or a gardener reaching for these insecticides to replace the chemicals he formerly used isn't truly following the organic method. If organic methods are truly followed -- composting, crop rotation, relying on specific cultivars and the nurturing of beneficial habitat for friendly bugs (that eat the bad guys) -- natural pesticides only become necessary as a last resort.

On this score, a horticulture professor, Jeff Gillman, has just written a book looking at the issue, and, according to the WaPo's gardening columnist Adrian Higgins, appears to have arrived at a reasoned approach: organic methods at heart are about feeding the soil and farming in such a way that reduces the need for pesticides. Higgins writes:

Gillman's fundamental argument -- to which I subscribe wholeheartedly -- is that if you are simply replacing synthetic products with organic ones, you are missing the point. The aim is to reduce the need for fertilizers and, especially, pesticides. How do you do that?

You build the soil with correct amounts of compost and mulch, choose plants that do well and place them in their optimum locations. "These are the true parts of organic gardening," says Gillman, a professor of horticultural science at the University of Minnesota.

But do organic farmers really follow these methods and avoid even those pesticides allowed in their arsenal?

The only work I've seen on this issue was in an annual farmer survey by the Organic Farming Research Foundation in 1998. It found that 52 percent of all organic farmers never used botanical insecticides and only 9 percent used them regularly. Other more benign methods such as insecticidal soap and Bt (a bacteria toxic to insects but not to humans) were cited slightly more frequently.

But what method did organic farmers most rely upon?  Crop rotation, cited by 74 percent. The reason rotation works is that it breaks up the habitat favored by a pest, never giving the pest a chance to breed in an ever-plentiful food supply.

Following Gillman's definition, it would appear that most organic farmers are, indeed, organic, though I would encourage OFRF to do a follow-up survey on organic pest and disease-reduction methods.

Image source: Biconet

- Samuel Fromartz