News and Reviews

The Pesticide Debate

September 12 2011 at 19:01

A guest blog – written for The Organic Supermarket by Dr. Oliver Moore

While food scares come and go, an ongoing concern people have is pesticide residues in food. A 2006 Eurobarmoter on consumer concerns about food found pesticides to be the single biggest food related concern, at 63%.[1]

Fast forward to 2010 and this time, pesticide residues again top the list. While 21% of people surveyed were not very concerned about food safety, of those that were, concern about pesticides topped the list. 72% in the EU, and 60% in Ireland were concerned about pesticide residues.[2]

On an intuitive level, a significant number of consumers seem to feel that, all other things being equal, they’d rather not take the risk of pesticide residues. This is an intuitive feeling rather than cold, rational, logical thought, because officially there are no issues for consumers with pesticides.

However, to use a slightly unusual sentence structure: there were no official issues with any of the things that there are now issues with, before issues emerged. This conundrum holds for both the mundane and the monumental. To take some examples: Before 1964’s US Surgeon General report, cigarettes were not a health issue. Before the mid 1970s DDT was used for head lice. Before 1961 Thalidomide was used  for morning sickness in pregnant women. And now, an egg a day is OK. Again. (it wasn’t OK for a few years, apparently).

It has always been thus. Before Louis Pasteur’s work in the 1850s, the theory of germs had not been developed. Indeed his theory was “ridiculous fiction” even into the 1870s, according to eminent Professors of Physiology at the time[3]. Can you imagine the explanations for germs that abounded before the discovery of germs?

In the meantime, debates rage, new products become available and agri-industrial processes and inputs become more globalised and complex. Scientific validation moves at a slower pace than the effects of the things science studies. And the balance between independent 3rd level institutions doing ‘pure research’ and the increasing importance of the business sector in supporting and defining what gets to get researched is a murky, messy one. If no one looks for X, because there is no money in looking for X, things plod along until, eventually, there is an issue.

Nanotechnology in food, as an example, is an under-chartered area but one which we as a society are falling blindly into without much research.

Nanotechnology, as the name hints, is about the use of sub-atomic sized particles in places they didn’t previously go. Used in everything from cooking oil to food packaging, nanotechnology masks smells and flavours, extends shelf life and encapsulates then transfers materials. A millionth of a millimetre in size, nanoparticles are small enough to get past the bodies’ normal barriers – such as skin, lungs and intestines.

Organic certification  bodies have taken the precautionary lead and started to disallow this new technology until further tests have been done. Meanwhile, things plod along and nanotechnology becomes more a part of the conventional agri-food system.

Organic legislation is ahead of the curve when it comes to the precautionary principle. The Soil Association have already disallowed nanotechnology from their Organic Standards.

Organic is also ahead of the curve when it comes to pesticides[4]. There is a curious situation at present, whereby officially there is nothing to worry about with pesticide residues, yet US, EU and other legislation keeps restricting the use of pesticides. To go back to our conundrum: some pesticides like Carbofuran can be perfectly safe and in use until the day they are banned, when all of a sudden they become unsafe – despite the fact that nothing has changed in how they function.

Coming down stream from the EU are the Plant Protection Products Regulation and the Directive on  Sustainable Use of Pesticides.  (“Plant Protection Products” is industry speak for pesticides used in farming) These will have to be written into legislation here in Ireland. So some restrictions on pesticide use are coming downstream.

But in organic farming standards, the vast majority of pesticides are banned completely already. There are severe restrictions on the tiny number that are technically allowable. While there are c.2000 biocides (i.e. both farming and domestic pesticides), c.1000 of which are for conventional farming, there are just 27 allowed under the Organic Standards. These include plant oils such as mint oil, beeswax, and other naturally occurring substances[5]. In organic farming, within the broad pesticides category,  no naturally occurring or artificial herbicides are permitted, and any of the tiny number of both fungicides and insecticides allowable must be naturally occurring under the organic standards. Even then, there are restrictions in the amount and frequency of use, permissions needed and withdrawal periods.

In short: There is 97% less pesticide use on organic as compared to conventional farms[6], and those that are used have severe restrictions on them.

Of course the context in organic farming is for these substances not to be used or needed at all: the whole point is to develop systems of food production that avoid pesticide and other similar problems by building a resilient well integrated farm, with natural and biological control built up the farming methods themselves. And this is how it is, the vast majority of the time for the vast majority of organic farmers.

This compares to the 64 pages of allowable pesticides in “Pesticides 2011”, published in February this year by the Pesticides Registration and Control Division of the Department of Agriculture.

1522 tonnes of “active substances” (i.e. the relevant element of a pesticide product) were used in conventional arable cropping in Ireland  according to the most recent data (2004)[7];  and another 567 tonnes on grasslands[8]. Globally, over 2 billion KG of pesticides are used annually[9] and at least 67 million birds die directly from agricultural pesticide exposure in the US alone[10], with anything up to 100 times that number actually dieing from such exposure.[11]

Inevitably in this sort of context, farmyard bird populations decline and biodiversity declines, in Ireland, the EU and the world, due to the overall effects of agri-industrial inputs, including pesticides. “Populations of farmland birds in Europe, which indicate the health of the ecosystem as a whole, have declined by almost 50% in the past 25 years” according to Birdlife International[12]. What’s perhaps most chilling is that many pesticides are lethal to birds even when used according to instructions. Chilling too is the fact that even when these are banned in Western Europe or North America, they are still used in other countries. In fact, they are often still manufactured in the US, where they would be illegal to use, and sold for use in Africa. [13] [14].

The little research that exists on the multiplier effect of pesticide residues in nature also points to nature being impacted negatively. This is another important and under-research area. In nature, what Relyea calls “suites of contaminants” are working on and in their surroundings all the time. His research on wetland fauna finds that they are “dramatically impacted” by low concentrations of pesticides[15].

Inevitably, if a multitude of pesticides are ingested over time, this will cause more damage than if a single pesticide is once.

The key point is that pesticides kill both target and non-target plants, insects and animals.

This is all to say nothing of the secondary deaths that occur from these poisoned creatures (e.g. bigger birds, bigger animals, and humans); or of human exposure in rural areas, especially near arable cropping fields; or human exposure in work, especially rural undocumented farm labourers in 3rd world countries; or even human exposure in the food chain.

In broader terms pesticides are part of an unsustainable agri-food system that is completely dependent on oil, contributes significantly to climate change and perpetuates that most anomalous of  historical blips: the western diet.

Organic farming may not have all the answers, but it steps in the right direction, a direction the rest of agriculture eventually follows. A key question however, is where will the Lion’s share of State and EU supports go over the next few years? Will they go to those operating to best practice, in everything from pesticide use to oil dependency, or will they go towards those who continue to drag their heals?

In the meantime, enjoy your organic food, safe in the knowledge that you are contributing towards planet-friendly best practice.




[4] Pesticide is used here, as is standard, as a generic term to cover all pesticides, herbicides, insecticides and fungicides


[6] Mäder, P., Fliebach, A., Dubois, D., Gunst, L., Fried, P., & Niggli, U. 2002. ‘Soil fertility and biodiversity in organic  farming. Science, 296 (5573):1694–1697.

[7] Department of Agriculture Fisheries and Food Pesticide Useage Survey 1 Grassland and fodder crops 2003 (2007)

[8] Department of Agriculture Fisheries and Food Pesticide Useage Survey 2 Arable Crops 2004 (2007)


[10] U.S. Fish & Wildlife Service Pesticides and Birds International Migratory Bird Day (2000)

[11] Ibid: quote: “biologists believe that for each bird carcass found and reported, approximately 100 others are never found.”

[12] Birdlife International

[13] Ibid and

[14] for a video on the effects of  a pesticide banned in the US in 2009 in Africa


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