DDT and pesticides. From miracle molecule to persistent problem.
Our continued struggle with pesticides
A spotlight on DDT. A few years ago, I read Rachel Carson’s iconic environmental book, Silent Spring, that helped kick-start the global climate movement. The cause was helped by a US senator and a university student/activist. The senator, Gaylord Nelson, and student, Denis Hayes, kept pushing the environmental movement and then in 1970 the very first Earth Day was born. Rachel Carson passed away before this but I’m sure she would have been very proud to see others take the relay.
When I read Silent Spring, I was shocked to learn how prevalent and persistent chemical spraying was (and still is!) and the horrendous destruction it has caused. It’s nearing 90 years since DDT, a particularly poisonous and widely used pesticide, was introduced. Even today we are still turning to chemical pest control, even though natural methods have always existed.
Rachel’s book created mass awareness and started change, but we have a long way to go.
The pesticide DDT
Dichlorodiphenyltrichloroethane, or DDT for short, was initially synthesised in 1874 by Austrian chemist Othmar Zeidler. Although it remained an apparently useless chemical, where it was just replicated by university students.
Fast forward to 1939 another chemist, Paul Hermann Müller, who had worked with DDT, noticed that it had killed a fly. Very quickly it became a potent pesticide. Müller even received the Nobel Prize in Physiology/Medicine in 1948.
Initially it seemed to work well with insect-born diseases like malaria and outbreaks like typhus, which is why it was mass produced during and shortly after World War II. The huge surplus of DDT, post WWII, was then used for agricultural purposes, mainly for pest control.
DDT chemical composition & destruction
Its composition seems simple where carbon and chlorine atoms are bonded together to make a very stable compound, yet its destruction is sly and unsparing where it destroys living organisms from within.
DDT is non-water soluble (it is highly fat-soluble), so it builds up in living organisms, causing:
-neurotoxicity,
-reproduction impairment,
-harm to embryos, and
-it is suspected to be a highly dangerous carcinogen
Certain flying creatures, like bees and birds, including the American Robin and falcons, took decades to recover – even though they were never a spray target.
In simple terms, the chemical spraying works like this:
-pest on a tree
-spraying the tree and its surrounding area
-chemical residue everywhere
-bees feeding on sprayed flowers
-rain
-chemicals seeping into the soil
-small animals in the soil absorbing it
-small birds eating the chemical-laced animals
-big birds eating the small birds
-chemicals seeping into rivers
-fish bathing in it…
Dangers of pesticide DDT & Silent Spring
The initial ‘success’ stories of DDT were short-lived. The deep destruction was a fast-approaching Tsunami.
DDT ended up endangering a number of insect, animal and plant species and the target pests did what they do well; they became resistant.
DDT and other synthetic insecticides were put under scrutiny after Silent Spring hit the shelves. This marked the start of a decline. Agricultural use of DDT was banned from the early 1970s onwards. Today, it is banned in most countries, but it has taken decades to get there.
Post DDT – Chemical spraying today
We have learnt a lot. But chemical spraying is still going on. Newer versions are continually produced, including the likes of neonicotinoids (neonics – a group of many insecticides – affect the brain and nervous system), pyrethroids (insecticide – similar affects) and glyphosate (herbicide – confirmed to cause cancer at ‘safe’ doses).
Neonics were widely used from the 1990s onwards.
Neonics like DDT attacks an organism on a neurological level, but they work differently chemically where they interfere with receptors that are more common in insects than other animals. Its application is more targeted, in the sense that it is applied to seeds directly and the soil around plants. Whereas DDT was applied to the surface and spread quickly via wind.
More studies on neonics are showing that their toxicity is high even at doses deemed ‘safe’. Neonics penetrate the crop, so they exist within it and cannot be washed off. They are long-lasting so they build up in all insect, animal and plant species.
During the 60+ years since Rachel’s book, we have had plenty of time to carry out more research. But it seems that we haven’t fully understood that incremental amounts of ‘safe’ doses equal toxic levels.
We are way too concerned about profit margins.
Pesticide threats to bees
Take our hero honeybee, they visit many different places to collect pollen for their hive, and power up on nectar. But then they often encounter a cocktail of chemicals that:
-disrupt learning and memory
-make bees sluggish
-causes paralysis
-causes disorientation
-causes memory loss – so the honeybees can’t find their way back to the hive
-have been the cause of habitat loss
-ultimately causes death for generations
A study by Clara Stuligross in 2020 looked at the impacts of pesticides on solitary wild bees who we have to thank for a huge number of accidental pollination. She found a lot of things, for example, the solitary bee that is ‘infected’ with chemicals:
-lays fewer eggs
-can consume pesticides as larvae and again as adult bees – so ingest a double dose
-impacts the future bee population worldwide
Pesticides & climate change
Pesticides and climate change impact each other negatively
-Chemical manufacturing is energy intensive and its use produces toxic gases
-These chemicals often come from fossil fuels
-Chemical spraying causes degraded soils and disrupts biodiversity
-Vicious circle: with climate change, warmer weather creates cosy conditions for new pests = more spraying
How do we save our bees/pollinators?
We need more bans on chemical spraying. Luckily they are coming in, albeit slow and inconsistent.
A few things that are an absolute must:
-Need for more Integrated Pest Management (IPM)
-Avoid spraying during spring/summer when bees are active
-At the very least limit dose of spraying
-Change farming practices
-Planting more unsprayed flowers!
-Increased awareness among all of us about bees and other pollinators!
-Celebrating days like World Bee Day – held each year on 20 May
More formal pest management:
-Shift towards Integrated Pest Management (IPM)
-there are a plethora of natural ways to combat a pest problem, especially biological controls e.g.
-introducing natural predators, like bats and dragonflies
-crop rotation where different crops are being grown every couple of years
-growing a variety of crops that are complementary
-Mechanical methods (like traps)
-Careful use of new chemicals only when absolutely necessary
-Although the more these newer chemicals are used the more we find out that they harm our nature and animals. For example, neonicotinoids are linked to bee-population declines, and glyphosate poses a huge cancer risk to animals and humans
Firmer and clearer regulation to protect our bees
-Firmer and clearer regulation to protect our pollinators, including:
-In 2013 the EFSA issued a guidance document with a number of instructions and standards to protect bees
-In 2023 the EC asked the EFSA to update this guidance document as not all of the instructions had been implemented
-In 2026, the French Agency for Food, Environmental and Occupational Health & Safety is taking specific action under the revised guidance document for its French bees
-Real regulation was needed, so in 2018 the EU set-up something more tangible: the EU Pollinators Initiative with specific objectives and actions to be taken by 2030 under the European Green Deal, where a host of other initiatives have been implemented that will also benefit pollinators, including the:
-Farm to Fork Strategy, and
-Zero Pollution Action Plan
A couple of final thoughts about pesticides – DDT is not the only killer:
-Chemical application should be an absolute last resort. Anything labelled as ‘safer’ chemicals are not really safe at all
-There are huge ongoing global disparities, because different countries have different laws and governments. We must push for pesticide reform and greater adoption of organic, local and regenerative agriculture
-For example when it comes to neonics, The European Union has a ban in place for outdoor use, but in the US for example, its use is only restricted
-We need to keep our eyes peeled for petitions against chemical spraying. Through a petition in 2025, France banned the reintroduction of a bee-killing chemical
-Although just a few weeks ago the senate passed a law to reintroduce two neonicotinoids! The roller-coaster continues… A new petition has been created…
I hope you found the article helpful. You can also hop over to the short-form content articles. Check them out here.
Sources:
Silent Spring (book), Earth Day, EC – IPM, nature – study, ACS – chemistry, Royal Society of Chemistry, PAN, NRDC – neonics, American Heritage – history, WHO – malaria, Science Direct, nature – bee study, EC – neonics ban, EPA – neonics study, NRDC – neonics, Medium – bees, EFSA, DeSmog, Lynxee consulting – France, EU – Pollinators Initiative, Science, Le Monde – duplomb