Neonicotinoids - unspeakably dangerous

Neonicotinoids - hardly anyone can pronounce them - are now considered by scientists to be just as dangerous as DDT, which was banned in the early 1970s. What is under discussion with glyphosate, namely how harmful it is to organisms, has been proven with neonicotinoids. For a sparrow, the consumption of 1-2 treated seeds is enough to reach the lethal dose.

Neonicotinoids were discovered in the 1970s and commercialized by Bayer AG in the 1990s with imidacloprid. "Neo-nicotin-oids" are synthetic nicotine compoundsthat act as neurotoxins. These are pesticides with a "systemic effect", which means that the active ingredients with which, for example, seeds are treated (=treated) before sowing do not remain on the seeds. Due to the good water solubility of neonicotinoids, they are transported further in the plant and spread to all parts of the plant, including the pollen and nectar. This is intentional, as it kills all pests that eat plant parts, be it the roots or the leaves.

The ease of use and supposedly low toxicity for mammals made neonicotinoids very successful within a short period of time and imidacloprid is now one of the most widely used insecticides worldwide.

More and more studies are showing a link between the use of insecticides from the neonicotinoid group and the collapse of bee colonies and reduction of pollinating insect species. In 2008, the neonicotinoid clothianidin, a successor to imidacloprid, caused a mass death of bee colonies in the Upper Rhine Valley ditch because the product adhered poorly to the maize seed.

When applied correctly, neonicotinoids are not directly lethal to bees, but they do lead to changes in behavior, such as poorer brood care, reduced food gathering and disorientation. The insecticides applied are of course not only absorbed by bees, but also by other nectar-gathering and herbivorous insects and creatures.

• Neonicotinoids are poorly absorbed by the treated plants, 94 percent of the amount applied is blown away and accumulates in the soil, water and other organisms(Nature 2014).
• In the next few decades, 40% of insect species will become extinct if we carry on as before. Neonicotinoids and fipronil are particularly harmful (Biological Conservation 2019).
• In the Netherlands, a sharp decline in insectivorous bird species has been recorded since the authorization of neonicotinoids in the mid-1990s in agricultural regions, especially where high concentrations of the neonicotinoid imidacloprid were used(Nature 2014).
• At least one neonicotinoid was found in the feathers of 617 sparrows around conventional and organic fields, and in much higher concentrations near conventional fields. The authors of the study conclude that neonicotinoids are already widespread in the environment (ScienceDirect 2019).
• The ingestion of 1-2 seeds treated with neonicotinoids can be fatal for small bird species(Environmental research 2015). Bird populations are therefore not only indirectly threatened by the decline in insects as a food source, but also by the direct ingestion of neonicotinoids, which leads to serious neurological disorders.
• In one study, lemon trees in greenhouses were treated with the neonicotinoids imidacloprid or thiamethoxam. The honeydew excreted by aphids and mealybugs that sucked on these plants was contaminated with the neonics - and as a food source poses an additional, previously unknown danger to bees, wasps, ants and hoverflies - 60 percent of the insects died shortly after the toxic meal(PNAS 2019)
• US agriculture is 48 times more toxic to honey bees than it was 25 years ago. This is almost entirely due to neonicotinoids. The dramatic increase in pesticides correlates with the decline in insects.(PLOS One 2019)
• Birds that ingested imidacloprid stopped eating for a while and drastically lost body weight - especially the fat content decreased significantly. This can be a death sentence for migratory birds, as they are then unable to survive the long distances(Science 2019)

After the European Food Safety Authority (EFSA) also confirmed the negative effect of neonicotinoids on bees, the European Commission restricted the use of three neonicotinoids in 2013 and banned them generally in 2018. This restriction applies to clothianidin, thiamethoxam and imidacloprid. However, five other neonicotinoids are still approved for plant protection. These include the substances acetamiprid, dinotefuran, nitenpyram, nithiazine and thiacloprid. They are considered to be less toxic to bees.

Furthermore, emergency authorizations for the use of neonicotinoids were granted in various EU countries, for example for sugar beet in Austria. The Federal Office for Food Safety thus gave in to pressure from the agricultural industry. The approval was based on the argument that sugar beet does not flower and therefore bees are not harmed. But what about Hongitau as a source of poison for bees? And what about all the other animals that ingest the neurotoxin? Don't forget that 94 percent of neonicotinoids applied end up in the soil, water and other organisms instead of the treated plant. Why is it not possible to ban all neonicotinoids as in France?

In Austria, 25 percent of the conventional sugar beet harvest was lost to pests in 2018, despite the use of neonicotinoids. In the organic sector, the figure was as high as 86 percent, as this was exacerbated by the lack of agricultural helpers for weeding.

Does this mean that we can't do without pesticides? No, unfortunately it means that we have long since abandoned the path of good agricultural practice and have wiped out the natural predators through decades of pesticide use. In Austria, 70 percent of vertebrates have been lost in the last 30 years, and farmland birds are particularly affected. The decline in insects is also enormous. A wide variety of agricultural structures such as hedges, fallow land and thus refuge areas for beneficial insects have been destroyed, and even organic farming, which is now on the increase, can only slowly make up for this. Sensible practices, such as growing humus-absorbing plants like sugar beet only every 6 years, have been forgotten.

If we want to regain biodiversity and break out of the vicious circle of dependence on chemical companies, we need agriculture without pesticides. A positive example of this is organic farming, which manages almost without, or in the case of Prüf Nach! completely without synthetic chemical pesticides. It is not without reason that organic farming is clearly superior to conventional farming in terms of biodiversity. According to a study published in January 2019, the average number of species of arable flora increased by 95 percent in organic farming, field birds by 35 percent and flower-visiting insects by 23 percent. The biomass of earthworms was 78 and 94 percent higher respectively.

Agriculture with diverse structures such as individual trees, hedges, uncultivated or mowed fallow land and meandering streams is needed. The training and sensitization of farmers plays a key role here, as does ensuring that the measures taken are affordable for farmers. This can be achieved either through subsidies from the federal states or through cost transparency. If farms had to bear the environmental costs that they cause, e.g. through the use of pesticides, this would be quickly achieved. Environmentally friendly and nature-protecting products would be the cheapest.

Agriculture used to be part of the natural landscape, not industry. It actually increased biodiversity instead of reducing it. It would be nice if we could return to this understanding.

About the author

Dr. Isabell Riedl has been working as a sustainability officer and in communications at Werner Lampert GmbH since 2012. She studied ecology with a focus on nature and landscape conservation and tropical ecology at the University of Vienna. She wrote her dissertation on the importance of tree rows in agricultural areas for forest birds in Costa Rica. Throughout her life, she has been particularly committed to ecological sustainability. She is part of the editorial team of the online magazine "Nachhaltigkeit. Rethink."