Pull up a chair, because we're about to make you feel conflicted about bug spray.

The Chlorpyrifos Paradox: Why Banning Bad Chemicals Isn't Enough

Claw-Pier-uh-fos.

Difficult to pronounce but deep implications.

Chlorpyrifos is a broad spectrum insecticide used in agriculture, introduced in 1965 by Dow.

It kills insects by inhibiting an enzyme critical to nerve function, causing the overstimulation of the bug's nervous system until it dies.

It was widely used for decades, at its peak in the 1990s, chlorpyrifos was applied to roughly 8 million acres of US farmland annually, in crops ranging from corn and soybeans to almonds and citrus. Before being banned in the EU in 2020 and the US in 2021, it was one of the most commonly used organophosphate insecticides in the world, generating hundreds of millions in annual sales.

Australia began its phase-out in 2019.

The problems with chlorpyrifos are extensive. It's highly hazardous to human health, linked to neurodevelopmental issues in children, reduced IQ, and attention disorders even at low exposure levels.

But it's also highly toxic to bees, birds, and fish. It binds to soil and sediment and has a half-life in the environment from 60-120 days depending on conditions persisting long after application.

Chlorpyrifos has been found contaminating waterways kilometers from application sites.

It’s an example of a nasty old chemical that exemplifies everything that is wrong with the agrochemical industry, and its banning should be expedited.

But this belies a deep underlying challenge that needs to be addressed.

The Innovation Drought

The broader market trend of banning damaging agrochemicals, when done thoughtfully, helps to make our food systems safer, environmentally friendly, and less extractive.

These are all good things.

But…

By removing these chemicals, growers have fewer and fewer tools to grow the food and fiber we need.

The numbers tell a stark story. Only four new insecticide modes of action have been brought to market in the past 30 years. Compare that to the 1960s-1980s, when dozens of new chemical classes were discovered and commercialised.

The situation is even more dire when you look at development timelines. It now takes an average of 11 years and $286 million to bring a new agrochemical from discovery to market, according to Phillips McDougall research. The success rate is low at roughly 1 in 100,000 compounds screened actually makes it to commercial registration.

Meanwhile, the regulatory hammer keeps falling. Since 2000, the EU has banned or severely restricted over 70 active ingredients. The US EPA has removed dozens more. These aren't just old, dangerous chemicals either. Many effective, relatively safe compounds are caught in the same net due to increasingly stringent (and sometimes scientifically inconsistent) regulatory standards.

The Grower's Dilemma

With fewer ways to protect crops from pests and disease, yields drop, quality suffers, grower margins (already razor thin, the average farm has a profit margin of just 2-3%) crash, and food prices soar.

Supply and demand writ large.

Resistance is accelerating the crisis. With fewer modes of action available, growers are forced to use the same chemicals repeatedly, which speeds up resistance development.

According to the Insecticide Resistance Action Committee (IRAC), over 600 species of insects and mites have developed resistance to at least one pesticide. Some pests, like the diamondback moth, are now resistant to virtually every major insecticide class.

The result of this is that growers face devastating crop losses with no effective response.

California almond growers have watched the navel orangeworm, once easily controlled, become increasingly resistant to available insecticides, costing the industry millions annually.

Cotton growers in Queensland and New South Wales have witnessed Helicoverpa (cotton bollworm) develop resistance to successive generations of insecticides, first organochlorines, then organophosphates, then synthetic pyrethroids, leaving growers with dwindling chemical options and severe yield losses before the eventual adoption of Bt cotton as a partial solution which is now also under pressure.

Building Rather Than Banning

The way to build a clean, green, safe food system isn't to simply remove tools. We need to build better, safer, more reliable tools so that growers can do what they do best:

Grow our food.

This means investing in innovation: biological pesticides, RNA interference technologies, precision application systems that reduce chemical use by 90%, and genuinely novel modes of action that break the resistance cycle.

It means sophisticated incorporation of true Integrated Pest Management procedures.

It means regulatory reform that distinguishes between genuinely dangerous compounds and those with manageable risk profiles, and that doesn't take 11 years and $300 million to approve a new chemistry.

And it means recognising that growers aren't the enemy of sustainability and safety. They're caught between impossible demands to produce abundant, affordable, perfect food while using an ever-shrinking toolkit and facing increasingly unpredictable climate and pest pressures.

Chlorpyrifos deserved to go. But if we don't replace what we're taking away we're just building a more fragile food system.

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