When Nicole van Dam lives in the USA, a roommate cleans her fruit and vegetables with a brush and a special fruit soap. The professor of molecular interaction ecology thought that was exaggerated at the time, but now she has to admit: her roommate was probably right. The Pesticide Action Network Europe has analyzed public data and found that increasing amounts of fruit and vegetables in the EU contain residues of pesticides, even though the use of these toxic substances should be reduced by 50 percent by 2030. The reasons for this can be very different, explains Nicole van Dam in ntv's "Climate Laboratory". Our preference for sweets is just as much related to this as the economic conditions for farmers. However, new cultivation methods, which are already being used in Africa, for example, show how farmers can improve their harvest by 20 to 30 percent without using pesticides.
ntv.de: What is the dirtiest fruit or vegetable in the world?
Nicole van Dam: The Pesticide Action Network Europe looked at data and unfortunately found that more and more pesticide residues are left, especially on fruit. For example, the kiwi did very poorly. In her case, the number of affected fruits has quadrupled, but apples can also be found in the top ten. That surprised me.
What's so surprising about that?
Actually, there is an agreement in the European Union that we want to use fewer and fewer pesticides. Some may have heard of the 2030 Biodiversity Strategy. It stipulates that the use of pesticides must be reduced by 50 percent by 2030 - especially the most toxic pesticides. It is therefore surprising when an analysis of the last few years shows that the stakes have increased. I personally found that very...I used the word "shocking".
How big was the increase?
The data shows that in 2011, pesticide residues were found in approximately 18 percent of samples for all fruit types combined. In 2019 data, that number rose to 30 percent. That is one and a half times as much instead of 50 percent less.
How can that be?
I don't stand next to the farmers in the field, but it may not be properly regulated in all regions of origin. So that pesticides are still being used that are no longer allowed to be used. There are also differences in the countries. Some allow pesticides that are already banned in other countries.
Are there countries where you can say that a particularly large number of pesticides end up on the fruit?
Yes, it is mentioned in the report: Spain, Italy and Greece are more often in the top ten. But you have to be careful, there can be various reasons. Maybe they produce differently. They may actually be using more pesticides. It may be that the fruit is cleaned less after harvest. Maybe other countries use just as many pesticides but use more water to wash them away. I don't know that. For apples, for example, the Netherlands tops the list. As a Dutch woman, I was a bit ashamed.
What is also astonishing about the results is that they are actually only EU data. Great Britain was not evaluated. No fruit and vegetables from non-European countries were examined either.
Exactly. This is only EU data that is measured, collected and made publicly available. A good record.
Is this data complete or do you expect the number of unreported cases to be even higher?
How this data is composed in detail, I do not know. Of course I hope they give a good picture and it's not worse. The result is bad enough because it's not just about biodiversity, but also about our health if we eat more and more pesticides.
But you will hardly be able to prevent this, because in fact almost all types of fruit and vegetables are affected.
I'm amazed too. But I'm also against the idea that we blame the farmers alone. We are all responsible for that. Farmers also have children who want to study or travel and need to earn money to do so. And you can earn a lot of money with fruit, it's a valuable product. But of course there is price pressure. We pay minimum wage, that's a good thing. But that makes harvest workers more expensive than in countries outside the EU. Farmers have to compete with them. Then they might be more likely to use pesticides to protect the fruit from pests and get nicer berries or cherries that they can sell better.
What do you need the pesticides for anyway? Why do you have to spray kiwis with it?
In nature, fruit and vegetables are constantly attacked by fungi, predators and pathogenic bacteria. The plants defend themselves against this with some form of defence. Anyone who has an allotment garden knows this for sure: you can always find snails or white flies on the cabbage. But as consumers, we don't want a bitten cabbage. Sometimes it is also less durable and rots too quickly. This is especially the case with fruit. We want an apple that is whole and looks nice.
Like Snow White.
Exactly. Nobody wants the apple to rot immediately after putting it in its bowl for three days at home.
But we don't want an apple full of pesticides either.
That's the problem. In nature, the plant defends itself with substances such as mustard oil glycosides. This is known from cabbage and Brussels sprouts and tastes a bit bitter. With these substances, the plant defends itself against predators and fungi. But the fact is that many people do not like bitter substances. We prefer it sweet. That's why breeders bred them out: You take seeds from a sweet cabbage and use them to grow an even sweeter one, and so on. That sells better. However, this also means that the plant can no longer fend off pests itself. That's why we have to use pesticides.
We weakened the plants to make them taste better?
Yes. We're not that different from caterpillars, they also like it a little sweeter (laughs). It's exactly the same with vegetables.
So in the end you have to choose between taste and pesticide exposure?
It doesn't have to be. My mother used to cut cucumbers and put them in salt to get the bitterness out. Appropriate measures have therefore been in place for some time. But tastes have changed so much over the past 50 years that we're a bit spoiled. Everything tastes sweet, apples always look great, are always the same size, always have a certain size, always a certain flavor.
Did that happen with vegetables too?
Yes. The cabbage has become sweeter. This has been done with chicory, although I like the bitter taste. With the cucumber too.
So if you eat a cucumber that tastes a bit bitter, is it healthier than a sweet one?
My grandmother always said: bitter in the mouth makes the heart healthy (laughs). But I don't know if that's generally true. Of course, the plant also defends itself against us with these bitter substances. We've bred her to be defenseless now, but I wouldn't want to eat her too bitter either. With the organic cucumber, however, you notice that it has more taste.
They're not that watery.
Does organic always mean less pesticide residues?
The Pesticide Action Network also analyzed organic vegetables in its investigation and found only a few residues. From this one can conclude that fortunately it is less burdened. But of course there is also much less data on organic vegetables and organic fruit. From a scientific point of view, the next thing to look at is whether the results are better because there is less residue or less data. That's what the researchers said too. But if it is a real organic product, these pesticides should not actually be used in cultivation.
Does washing the fruit or peeling the vegetables help? That's what you should do.
That is an option. Let's take the kiwi, you rarely eat it with the skin on. Berries, on the other hand, should be washed thoroughly. I used to work in America for a while and lived in a flat share. A roommate always cleaned her fruit with a brush and a special fruit soap. I thought that was exaggerated at the time, but apparently she was right. Especially if you don't eat organic fruit and vegetables.
But if you grow vegetables in the allotment like you do, there's nothing to worry about, right?
The danger is very small. The neighbor would have to run a large corn field and distribute the pesticides by plane, as we know from America. Then it can happen that your own vegetables are hit if the wind is wrong. But nobody uses pesticides in my small garden. You have to be more careful not to find any codling moth caterpillars in your apples.
How bad is this pesticide exposure actually for humans?
Of course, these pesticides are always being researched. Thanks to toxicological tests, we know exactly which values are dangerous for us. The problem is that different pesticides sometimes mix. This is also stated in this study. And when you have more than one pesticide, you can't just add them up. There are effects where one plus one might equal three. If you consume that for years, it affects the genome or the brain.
And how do these pesticides affect the environment?
The best known example are honey bees, they are very affected by it in many ways. It doesn't have to be immediate death, but they sometimes bring the pesticides into the nest and feed them to their larvae. Or they become more susceptible to certain mites, which then kill them. Or their immune system is attacked. There are also studies in which their behavior changes and they can no longer take good care of their nest. The other problem is that these pesticides don't break down very quickly, they're stable. If farmers keep using pesticides, the soil will become enriched with them. And we are just learning how important living soil is for agriculture. We have neglected them. When there are a lot of pesticides in it, you practically slaughter the chicken with the golden eggs, as we say.
Is there any fruit or vegetable that you say has adapted incredibly well to these pesticides?
We once had a project where we looked at how peppers defend themselves against thrips. These are small animals that are already resistant to pesticides. That's another problem: some pesticides no longer work at all because insects have developed a way to detoxify themselves. In the project we studied three types of thrips. My doctoral student always said: I hope we find a pepper that beats everyone! Unfortunately we don't. The animals, insects and fungi are also constantly adapting. That's why we always have to come up with new clever ways of protecting our plants. It's a kind of race. We are unlikely to find a vegetable that can do everything. But we can adapt our cultivation methods. For example, by not cultivating the land with one plant, but planting different vegetables. This is called strip cropping.
Large monocultures are rather bad?
Exactly. If you grow different plants, many natural enemies of thrips come into the field, such as parasitic wasps or smoke mites. They eat the thrips or caterpillars. A new idea that I also really like and that is already working very well in Africa is the push-pull system: you plant corn and plants that smell funny in between. They chase the animals out of the field with their smell. That's the push. The pull occurs at the edge of the field: Plants are planted there that attract insects. Then they can eat them.
You put out bait and say: You can eat here, not here.
Yes, for example with fragrances. If the farmer then finds that the tasty plant arrives at the side of the field with the insects, he could also remove it and thus destroy a large number of insects at once. You will never be able to eliminate them all, but it has been shown that you can improve harvests by 20 to 30 percent with such a system.
Do you see your research being taken up and the use of dangerous pesticides in the EU declining? That's what the EU Commission claims. In 2019, 12 percent fewer pesticides are said to have been used than between 2015 and 2017. But it doesn't look like that.
Many of my colleagues and I are passionately searching for new, better methods. But our research always fails because of politics or money. There is a lack of willingness to support farmers who want to change their business. Because of course you can't sell the harvest as expensively as other organic farmers in the first few years of switching from conventional to organic farming. One should also ask: Does an organic apple necessarily have to be more expensive than a conventional apple? Can we do something so that people with less money can also afford organic fruit and vegetables? Food prices are currently rising. And then we can't blame people on the subsistence level for not buying organic.
Clara Pfeffer and Christian Herrmann spoke to Nicole van Dam. The conversation has been shortened and smoothed for better understanding.
(This article was first published on Thursday, June 16, 2022.)