How are proponents of regenerative agriculture supposed to respond to news like this?

Green pesticide and herbicide developer Marrone Organic Innovations is nearly done raising $7 million in a second round of funding, CEO Pamela Marrone said Wednesday.

Wow, somebody’s investing in organic agriculture — millions, no less. That’s news. But does it have to involve pesticides?

Pesticides aren’t just problematic because they’re derived synthetically. They’re also troubling because what’s toxic to plants and insects also harms people. Plant-based substances, in concentrated form, can of course be quite toxic.

Moreover, using them usually means entering a “pesticide treadmill.” Say a certain pest is eating your tomato plants. You could hit them with a dose of Sevin Dust, a popular home poison. The Sevin will kill most of your pests and save the crop. But the few that survive will reproduce — and pass on the traits that made them resistant to Sevin.

The next season, these hearty offspring will be ready to pounce on your tomatoes, and you’ll need a heavier dose of Sevin — or an even stronger poison — to kill (most of) them. And so it goes — ever more-robust insects, and ever-harsher poisons to attack them. Losers in this game include farmworkers, consumers who get residues on their produce, beneficial insects that might otherwise feed on the pests, and entire ecosystems around your tomato patch. Among the winners are the big petrochemical companies that fuel the treadmill with their pesticides.

Old-school organic agriculture seeks to throw a wrench into the pesticide treadmill. Rather than fight pests actively by poisoning them, traditional organic farmers nurture pests’ natural predators — the insects that eat the insects that eat crops. Doing so usually means seeding certain flowering plants amid the usual crops. Turns out plant biodiversity leads to bug biodiversity — and balance balance between pests and their predators (so-called “beneficial insects”).

In this farming style, another goal is vibrant, healthy plants that can shake off a little insect damage — not ones jacked up on jolts of synthetic nitrogen fertilizer. (Such nitrogen-lashed plants have proven very attractive to insects. The boom in synthetic fertilizer after World War II created a massive market opportunity for petrochemical pesticide makers.) Thus old-school organic farmers put a lot of energy into building their soils, nurturing underground ecosystems in the field that teem with microorganisms, decaying organic matter, and earthworms.

Sure, things get out of whack, pest populations sometimes overwhelm, and it’s important for commercial growers to have organic-approved “biopesticides” at their disposal for emergencies. According to an Organic Center lit review [PDF], these are “much less toxic per pound of active ingredient” than their synthetic peers. But many of them wipe out wide varieties of insect, and — when relied on heavily — can create pesticide treadmills. Thus old-line organic farmers use them minimally, if at all.

Marrone Organic Innovations and its investors seem to be promoting a different model for organic farming: input substitution. In this vision, organic farming mimics industrial-style farming — the trick is to find a “natural” substance to replace every synthetic one.

And of course, this is precisely the kind of agriculture that characterizes the large farms that stock the organic sections of the nation’s supermarkets. Marrone has no doubt hit upon a lucrative business model supplying such farms. It’s no wonder that venture capitalists are lining up.

According to the above-linked article, Marrone is tantalizing them with the promise of what it calls its “big win,” a “greener alternative to the wildly successful herbicide Roundup.” Whoa. Now, Roundup is a lucrative model indeed. GM seed giant Monsanto clocks something like a billion bucks a year in profit from it. But this classic broad-spectrum herbicide has farmers over a huge swath of farm country on a classic pesticide treadmill — they’re hounded by superweeds that can’t be killed without ever-higher Roundup doses.

Would a bio-based alternative to it be a “big win” for organic agriculture?

In one of the weedier fields at Maverick Farms, we planted rye grass and hairy vetch last fall. Now that it’s several feet high, we’re going to mow-kill it, leaving what amounts to a blanket of hay over the field. Then we’ll plant tomato starts right into it, without tilling. The hay blanket will keep down weeds, and conserve moisture as well (important if last year’s drought conditions return). It will also provide a nice habitat for earthworms.

In the end, I suspect, we’ll find that organic farming works best when it mimics nature, not multinational chemical companies.