Tractor spraying pesticides at corn fields © fotokostic

The wide-scale application of pesticides is contributing to global biodiversity decline and threatens ecosystem health. The use of pesticides is increasing worldwide, and new substances are continuously being added to the market despite recent efforts to reduce their use.

The Food and Agriculture Organization of the United Nations (FAO) defines pesticides as any substance or mixture of substances made up of chemical or biological ingredients that are intended to repel, destroy or control pests, or to regulate plant growth. Examples include insecticides, fungicides, herbicides, molluscicides, and plant growth regulators. Pesticides often have long-term consequences for invertebrates beyond the target species. Buglife evaluates research and where necessary leads campaigns to effect changes to the use of toxins that are threatening the survival of essential species.

Pesticides of most concern   Pesticides use in conservation

Pesticides and invertebrates

Pesticide toxicity has more than doubled for many invertebrates since 2005 and has detrimental impacts on pollinators, soil-dwelling insect communities as well as freshwater invertebrates. Studies show the damage to insect diversity caused by hazardous pesticides even at concentrations that are deemed to be environmentally safe.

Pesticides are not the only chemicals that can harm invertebrate populations; there are also significant risks from veterinary and human medicines. Pesticide active substances that have already been banned for use on agricultural crops continue to be used in veterinary medicines for dogs and cats, causing chemical pollution in the environment.

Insecticides, fungicides and herbicides that are applied to crops often accumulate in the soil and can persist for years or decades after they are applied, continuing to impact soil heath. Research shows that insecticides cause most harm to non-target species such as ground beetles, ground nesting solitary bees, parasitic wasps, millipedes, centipedes, earthworms and springtails. Herbicides and fungicides are especially detrimental to earthworms, nematodes and springtails.

It has also long been recognised that pesticides used on crops, often damage field margin ecology. For instance, neonicotinoid insecticides contaminate wildflowers growing in field margins, hedgerows and adjacent meadows where they poison bees and other insects visiting flowers, causing many bee species to disappear from large areas of the countryside. Studies have also demonstrated the persistence of neonicotinoids in soil for multiple years, contaminating successive crops, spreading into field margins and meadows, poisoning pollen and nectar in wildflowers and having negative impacts on a wide range of free-living organisms, even at very low concentrations.

There are also concerns that birds and mammals will be poisoned if they eat treated seeds. The hazardous chemical pesticides also wash off and leach into rivers and streams causing severe pollution, and exceeding levels that trigger acute and chronic harm to aquatic life in rivers.

Spotted Longhorn (Rutpela maculata) on umbel flowers © Dave Price (Flickr, CC) Spotted Longhorn (Rutpela maculata) on umbel flowers © Dave Price (Flickr)

Pesticides and legislation

There are numerous issues surrounding the pesticide testing procedure, including the limited scope of testing – for instance no testing is done of the impacts of new pesticides on solitary bees, bumblebees, or even long-term health of honeybees. Further issues with current legislation include highly toxic “secret” ingredients in pesticides (co-formulants) are not publicly declared as being ‘active substances’ so never go through the approval process. No account is being taken of the ‘cocktail’ effect where pesticides can have more dramatic effects when working in combination with each other.

Currently there are over four hundred active substances approved for use in pesticide products in the European Union (EU). Since the approval process started in 1991, over a hundred have been banned due to their detrimental effect on the environment or human health.

Legislation © Pgiam Legislation © Pgiam

New decisions taken under the EU regime no longer apply in the United Kingdom (UK). Following , the underlying EU law in relation to the regulation of plant protection products was retained in UK law. From January 2021 an independent pesticides regulatory regime became operational, diverging from the EU regime. This includes active substance and maximum residue level (MRL) decisions and any new EU plant protection product (PPP) legislation.

The most significant change to UK pesticide regulation is that the role of the European Food Safety Authority has not been replaced. This body, with a budget of £80 million per year and ten committees of independent expert scientists, supported by teams of scientists, reviews the safety information provided by pesticide companies. It compares it to any independent scientific evidence and produces a public summary document indicating if there are areas of outstanding concern. This stage of the pesticide assessment process seems to have been dropped by the UK.

Locust © Pixabay

The UK pesticide ‘approval process’ is now less protective of people and the environment, but further afield pesticide regulation is even more haphazard, or influenced by industry. The United Nations identified that 25% of developing countries do not have any meaningful pesticide regulation process and described the international pesticide market as a human rights abuse. Most countries do not apply sufficient resources to implement pesticide law, and despite the wealth of evidence of environmental harm, even countries such as Canada and the USA have been unable or unwilling to ban neonicotinoids.

Pesticides of most concern

Agriculture© Pixabay Agriculture© Pixabay

What must happen?

In order to reduce pesticide harm on invertebrates and the wider environment, further actions are required.

  • Robustness of the pesticide approval ‘test methods’ must be improved, and a stronger evidence base developed for a wider range of beneficial insect species.
  • As part of a review of pesticide uses, there must be a full assessment of the environmental risks posed by pesticides to bumblebees, solitary bees, hoverflies, moths, and other insects, but also to groups such as earthworms, beetles, snails and aquatic invertebrates through residues in soil and in aquatic habitats. The assessment must enable the application of the precautionary principle.
Peacock Butterfly © Amy Lewis Peacock Butterfly © Amy Lewis
  • The link between advice to farmers and pesticide profits must be broken. Farmers deserve truly independent advice from people who are just as motivated and trained in non-chemical and ecological approaches to managing land for the joint outcomes of producing food and conserving biodiversity.
  • Domestic pesticide uses and municipal use by Local Authorities must be banned.
  • More monitoring of veterinary and human medicines needs to be introduced; more substantive responses to environmental risks need to be initiated; and a greater role for environmental risk assessment introduced into the approval process for these potentially very harmful substances.
  • Water quality must be improved – with reductions in harmful chemicals.
  • Harm from pesticides is a global issue that would benefit from an international convention to establish the principles of protection for people and wildlife, to promote greater transparency, to achieve more protective regulation, and to ensure that pesticide harm is not simply exported from countries with sophisticated regulation to less fortunate countries.

Pesticides use in conservation

Garden Bumblebees (Bombus hortorum) visiting Spear Thistle (Cirsium vulgare) © Kim Taylor Garden Bumblebees (Bombus hortorum) visiting Spear Thistle (Cirsium vulgare) © Kim Taylor

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